CBSE Class 8 Science Chemical Effects of Electric Current Assignment

Read and download free pdf of CBSE Class 8 Science Chemical Effects of Electric Current Assignment. Get printable school Assignments for Class 8 Science. Class 8 students should practise questions and answers given here for Chapter 14 Chemical Effects Of Electric Current Science in Class 8 which will help them to strengthen their understanding of all important topics. Students should also download free pdf of Printable Worksheets for Class 8 Science prepared as per the latest books and syllabus issued by NCERT, CBSE, KVS and do problems daily to score better marks in tests and examinations

Assignment for Class 8 Science Chapter 14 Chemical Effects Of Electric Current

Class 8 Science students should refer to the following printable assignment in Pdf for Chapter 14 Chemical Effects Of Electric Current in Class 8. This test paper with questions and answers for Class 8 Science will be very useful for exams and help you to score good marks

Chapter 14 Chemical Effects Of Electric Current Class 8 Science Assignment

Question 1. Fill the blanks.

(a) Most liquids that conduct electricity are solutions of acids, bases and salts.
 
(b) The passage of an electric current through a solution causes chemical effects.
 
(c) If you pass current through copper sulphate solution, copper gets deposited on the plate connected to the negative terminal of the battery.
 
(d) The process of depositing a layer of any desired metal on another material by means of electricity is called electroplating.
 
Question 2. When the free ends of a tester are dipped into a solution, the magnetic needle shows deflection. Can you explain the reason?
Answer- Yes, because solution is conductor of electricity.
 
Question 3 Name three liquids, which when tested in the manner shown in Fig.14.9 may cause the magnetic needle to deflect.
 
8th.sci.eng.july.Aug 10
Answer-Vinegar, Lemon juice and tap water.
 
Question 4. The bulb does not glow in the setup shown in fig. 14.10. List the possible reasons. Explain your answer.
8th.sci.eng.july.Aug 11
 
Answer- The bulb may not glow because of the following reasons:
(i) Liquid in the beaker may be non-conducting.
(ii) The battery may be exhausted and does not have sufficient energy to generate electricity.
(iii) The bulb may be fuse.
(iv) Connections may be loose.
 
Question 5. A tester is used to check the conduction of electricity through two liquids. Labelled A and B. it is found that the bulb of the tester glows brightly for liquid A while it glows very dimly for liquid
B. you would conclude that
(i) Liquid A is a better conductor than liquid B (✓)
(ii) Liquid B is a better conductor than liquid A
(iii) Both liquids are equally conducting
(iv) Conducting properties of liquid cannot be compared in this manner.
 
Question 6- Does pure water conduct electricity? If not, what can we do to make it conducting?
Answer- No. Pure water does not conduct electricity. This is because pure water do not have any free ion. Pure water can conduct electricity when a pinch of common salt is added to it, as salt solution is conducting in nature.
 
Question 7. In case of fire, before the firemen use the water hoses, they shut off the main electric supply for the area. Explain why they do this.
Answer- Water usually contains salts and conducts electricity. If the electrical supply is not cut off and firemen come in contact with wet electric switches, electric wires and other electrical appliances, he can get electric shock.
 
Question 8. A child staying in a coastal region tests the drinking water and also the seawater with his tester. He finds that the compass needle deflects more in the case of seawater. Can you explain the reason?
Answer- Water we use for drinking purposes has very less amount of salts dissolved in it while sea water has very high concentration of salts in it. So, compass needle shows more deflection in case of sea water.
 
Question 9. Is it safe for the electrician to carry out electrical repairs outdoors during heavy rain pour? Explain.
Answer- No. It is not safe to repair electrical appliances outdoors during heavy downpour. This is because rain water contains small amounts of acids in it which makes it a conductor of electricity. So, the electrician may get electrical shocks while working outdoors during rain.
 
Question 10- Paheli had heard that rainwater is as good as distilled water. So, she collected some rainwater in a clean glass tumbler and tested it using a tester. To her surprise she found that the compass needle showed deflection. What could be the reason?
Answer- Rain water is said to be pure water. But many impurities and acidic gases get dissolved in the rain water while it falls to the earth through the atmosphere. Due to the presence of these impurities and small amounts of acids in it, the rainwater conducts electricity.
 
Question 11. Prepare a list of objects around you that are electroplated.
Answer- The objects which are electroplated are:
(i) Taps of water connection.
(ii) Parts of bicycle.
(iii) Body of cars, motor cycle and tractors.
(iv) Handles of the doors.
 
Question 12- The process that you saw in Activity 14.7 is used for purification of copper. A thin plate of pure copper and a thick rod of impure copper are used as electrodes. Copper from impure rod is sought to be transferred to the thin copper plate. Which electrode should be attached to the positive terminal of the battery and why?
Answer- The thick rod of impure copper should be attached to the positive terminal of battery. This is because the copper ions of the solution will get deposited on the thin rod and the loss of copper from the solution will be restored from the thick rod to the positive terminal of the battery. Thus, copper from the thick rod could be extracted out..
 
ONE MARK MCQs
 
1. Veena has read that some substances are good conductors of electricity where as some are bad conductors. Among the following which substance is good conductor of electricity?
a) Copper    b) Silver    c) Iron    d) All of the above (✓)
 
2. Today Rohit came to know that in the ancient times people used a device to detect direction. What was that device called?
a) Voltmeter    b) Ammeter    c) Magnetic Compass (✓)    d) All of the above
 
3. Manish today read about various effects of electric current. Electric bulb works on which effect of electric current?
a) Heating effect (✓)    b) Magnetic effect    c) Chemical effect    d) All of the above
 
4. Neeta's mother today brought gold plated silver jewelry. What is the process of plating one metal on another metal called?
a) Vaporization    b) Electroplating (✓)    c) Distillation     d) All of the above
 
5. Dhruv was very happy to see traffic signals in the city. What kinds of lights are used in traffic signals?
a) Tungsten bulb    b) LED bulb (✓)    c) Neon bulb     d) None of the above
 
6. Meenakshi broke a dry cell today. She got a black colored rod from it. What is this rod called?
a) Electrode (✓)    b) Electrolyte    c) Insulator    d) All of the above
 
7. Heera singh is surprised that the flow of electric current breaks the water into hydrogen and oxygen. Can you tell me that due to which effect of current this happens?
a) Heating effect    b) Chemical effect (✓)    c) Magnetic effect d) All of the above
 
8. Today Baljinder saw in science lab that lemon juice is good conductor of electricity. Among the following which is good conductor of electricity?
a) Vinegar    b) Tap water    c) Tomato juice    d) All of the above (✓)
 
9. Electricity repair is going on at sewak's house. He saw that handles of electrical repairing tools are made up of plastic. What is the reason for this?
a) Plastic is good conductor of electricity.    b) Plastic is bad conductor of electricity. (✓)
c) Plastic generates electricity.                   d) None of the above.
 
10. Pankaj knows that pure water is bad conductor of electricity. If you dissolve salt in water what will happen?
a) Water will become good conductor of electricity (✓)                  b) Water will become bad conductor of electricity.
c) Water will neither become good conductor nor bad conductor.   d) None of the above.
 
11. Sanjeev noted that there is layer of another metal on iron vehicles. Why is this done?
a) To prevent rusting.                      b) To increase the strength of iron.
c) To make the surface shiny.         d) All of the above. (✓)
 
12. Rupinder and Noor attached one end of a LED bulb with a cell and other with a screwdriver. If screwdriver is made of iron then what will happen if it is attached to the other terminal of cell?
a) Bulb will glow(✓)    b) Bulb will not glow    c) Can't say anything    d) Bulb will blink.
 
13. Robin stood near motorcycle and asked his father that the rim of wheel is made of iron but why is it more shiny then normal iron?
a) Due to more driving                                            b) Motorcycle is new
c) There is plating of another metal on iron (✓)        d) Can't say anything.
 
14. On passing electricity through copper sulphate solution, copper will deposits on the plate connected to which terminal of battery?
a) Positive terminal    b) Negative terminal (✓)    c) Both terminals    d) None of the both.
 
15. While electroplating of copper which liquid is added to make the copper sulphate solution more conducting?
a) Sulphuric acid (✓)    b) Sodium Hydroxide    c) Sugar solution    d) Kerosene oil
 
16. Out of below given options which is the use of magnetic effect of current?
a) Electroplating    b) Electric Iron   c) Electric Bulb    d) Electric Bell (✓)
 
17. Rajesh's father brought a LED from market. Rajesh noted that one wire of LED is long and another is short. The Long wire is connected to which terminal of battery?
a) Positive terminal (✓)     b) Negative terminal   c) Neither positive nor negative    d) Any terminal
 
18. Pari's father told her that air is bad conductor of electricity. But Pari has seen the lighting moving toward ground very fast in rainy season even though it was not raining at that time. What is then reason for this?
a) Due to low temperature    b) Due to more humidity in air (✓)
c) Due to high wind speed    d) All of the above
 
19. Some articles e.g. some parts of cars, taps and gas burners have plating of chromium on them.Among the given statements which is not correct for chromium?
1. Chromium has shine. 2. Chromium does not corrode. 3. Chromium is very cheap.
a) 1 (✓)   b) 2 (✓)   c) 3    d) All of the above.
 
20. Which object can be used instead of iron nail in given circuit so that flow of current remain uninterrupted?
a) Graphite (✓)   b) Plastic    c) Wood    d) Rubber
 
21. Which statement is incorrect regarding electroplating?
1. Electroplating is the process of plating one metal on another metal.
2. It is helpful in disposal of industrial chemicals.
a) 1 (✓)   b) 2   c) Both statements are correct. d) Both statements are incorrect.
 
22. Today teacher asked four students to bring magnetic compass from science lab. Students brought the devices according to table given below. Which student brought the right device?

8th.sci.eng.july.Aug 12

a) Amanjot   b) Rohini   c) Meera (✓)   d) Gagandeep
 
23. A tester is used to check the conductance of two liquids labelled A and B. It is found that the bulb of the tester glows brightly for liquid A, while it glows very dimly for liquid B. You would conclude that:
a) Liquid A is better conductor than liquid B. (✓)    b) Liquid B is better conductor than liquid A.
c) Both liquids are equally conducting.
d) Conducting properties of liquids can't be compared in this manner.
 
24. In the below given activity two carbon roads from two waste dry cells are connected with battery and then dipped in a bowl containing water. After sometime bubbles of gases appeared around carbon rods. These bubbles are of which gases?
a) Nitrogen and Chlorine             b) Oxygen and Hydrogen (✓)
c) Oxygen and carbon dioxide     d) Sulphur dioxide and Oxygen
 
25. Prem is having electric fittings in his house, someone advised to used LEDs in place of ordinary bulb. LED is better than ordinary bulb because:
a) LED consumes less energy.    b) LED is lightweight    c) LED is long lasting.    d) All of the above. (✓)
 
26. Among the substances given below which is not a good conductor of electricity?
a) Aluminum   b) Mercury   c) Graphite   d) Distilled water (✓)

 

I Fill in the blanks:-

1. A Compound formed by ions is called ________ .

2. The electrode connected to the negative terminal is _________ .

3. Distilled water does not conduct _______.

4. Electroplating is an important use of _______ .

II Choose the correct option:-

1 A liquid metal that conducts electricity :-

(a) Sodium (b) Mercury (c) Lead (d) Gold

2. An atom or a radical that becomes charged is called :-

(a) Radical (b) ion (c) electrode (e) none

3. Metals are extracted from their ores by the process of :-

(a) electroplating (b) electrolysis (c) both (d) none

III Name the following:-

1. An atom that loses an electron

2. Cell used in electrolysis

3. A liquid or a moist paste that has ions in it

IV Define the following:-

1. Electrolysis.

2. Electroplating.

3. Electrolyte.

4. Electrode.

V Draw the following diagrams and label it.

1. Electroplating steel spoons with silver.

2. Flow of ions in an electrolyte.

3. Electrodes.

VI Give reasons for the following:-

1. An acid or ionic salt added to water during the electrolysis of water.

2. Water taps are coated with nickel or chromium.

VII Answer the following in not more than 20 words:-

1. Define anode and cathode.

2. Mercury is a liquid that conducts electricity. What constitutes a current through it ?

VII Answer the following in not more than 40 words :-

1. What happens when a voltage is applied across electrodes placed in an electrolyte ?

IX. Label the diagram and answer the following questions

1. Give a suitable heading to the diagram given below.

2. Name the electrode which collects hydrogen .

3. Name the electrolyte.

4. Write a chemical equation for the process given below.

 CBSE Class 8 Science - Chemical Effects of Electric Current (1)

1.Positive terminal of the cell is indicated by:
(A) The shorter line.
(B) The longer line.
(C) Either of the two lines.
(D) None of these.

2.Symbol of a cell in an electric circuit is represented by:
(A) A longer line and a shorter line.
(B) A longer and a shorter vertical parallel line.
(C) A horizontal longer line and a vertical shorter line.
(D) A vertical longer line and a horizontal shorter line.

3.Battery is having:
(A) Two or more cells connected to each other in any manner.
(B) Positive terminal of one cell is connected to the positive terminal of the next cell.
(C) Two or more cells connected in such a way that the positive terminal of one cell is connected to the negative terminal of the next.
(D) Only one cell.

4.Lines connecting the various components represent:
(A) Wires.
(B) Terminals of the battery.
(C) Battery.
(D) Key.

5.Switch can be connected:
(A) To the positive terminal of the battery only.
(B) Anywhere in the circuit.
(C) To the negative terminal of the battery only.
(D) If required only.

6.When the switch is in the OFF position, the circuit is incomplete. It is said to be:
(A) Open and the current does not flow in the circuit.
(B) Closed and the current flows in the circuit.
(C) Closed and the current does not flow through any part of the circuit.
(D) Closed and the current does not flow through the bulb only.

7.A coil of wire present in electric heater is called:
(A) An element.
(B) A compound.
(C) A mixture.
(D) A solution.

8.In all primary cells chemical energy is changed into…………… energy.
(A) Potential.
(B) Kinetic.
(C) Electrical.
(D) None.

9.Appliance, which do not use electric energy:
(A) Geyser.
(B) Pressure cooker.
(C) Mixie.
(D) Immersion rod.

10.The decomposition of an electrolyte when electricity is passed through it is called:
(A) Electroplating.
(B) Electrolysis.
(C) Conduction.
(D) None.

11.The electrical process of coating an inexpensive conductor with a metal is called:
(A) Electroplating.
(B) Electrolysis.
(C) Conduction.
(D) None.

12.……………..is used in the extraction of metals from their ores.
(A) Electroplating.
(B) Electrolysis.
(C) Conduction.
(D) None.

13.. ………… is used for refining certain metals such as copper and zinc.
(A) Electroplating.
(B) Electrolysis.
(C) Conduction.
(D) None.

14.What is electrolysis?

15.Name the vessel consisting of electrodes and electrolyte in which electrolysis takes place.

16.What is current?

17.Name two sources of electric current.

18.What is meant by an electric circuit?

19.What is a battery?

20.Which type of energy is converted into electrical energy in an electric cell?

21.Which effect of electric current is utilized in electroplating?

22.Why is an acid or an ionic salt added to water in the electrolysis of water?

23.Give one term for each:
(i) The electrode through which current enters the electrolyte.
(ii) The electrode connected to the negative terminal of the battery.
(iii) Purifying metals by using electrolysis.

24.When the switch is in the ON position, the circuit from:
(A) The positive terminal of the battery to the negative terminal is complete.
(B) The circuit is said to be closed.
(C) Current flows throughout the circuit instantaneously.
(D) All of these.

25.The thin wire that glows when current passes through a bulb is called:
(A) Tungsten.
(B) Filament.
(C) Fuse.
(D) Terminal.

26.The bulb gets fused when:
(A) The bulb becomes milky.
(B) The filament is broken.
(C) The glass has broken.
(D) The bulb has become too old.

27.It is unsafe:
(A) To touch a lighted electric bulb.
(B) To carry experiments with electric supply from the mains.
(C) To use electric cells for experiments.
(D) Both (a) and (b).

28.A wire gets _______ when an electric current passes through it.
(A) Weak.
(B) Dull.
(C) Hot.
(D) Cold.

29.The amount of heat produced in a wire depends on its:
(A) Length only.
(B) Thickness only.
(C) Both length and thickness.
(D) Material, length and thickness.

30.The filament of an electric bulb glows on passage of current because:
(A) It has got heated to a high temperature.
(B) It is very thin.
(C) A chemical reaction takes place in the bulb.
(D) All of these.

31.The ISI mark on an electric appliance ensures that:
(A) The appliance is safe.
(B) Wastage of energy is minimum

32.Excessive currents in electrical circuits are the consequence of:
(A) Direct touching of wires.
(B) Connecting many devices to a single socket.
(C) Faulty wiring.
(D) All of these.

33.The needle of a compass:
(A) Is a tiny magnet that rests in North - South direction.
(B) Gets deflected when a magnet is brought close to it.
(C) Gets deflected when current flows in a nearby wire.
(D) All of these.

34.Magnetic effect of the electric current:
(A) Means that a wire behaves like a bar magnet on passage of electricity.
(B) Is utilized to make magnets.
(C) Was first observed by Hans Christian Oersted.
(D) All are correct.

35.Which one is good conductor of electricity:
(A) Wood.
(B) Glass.
(C) Silver.
(D) Plastic.

36.Which one is bad conductor of electricity:
(A) Wood.
(B) Copper.
(C) Silver.
(D) Gold.

37.The process of depositing a layer of any desired metal on another material by means of electricity is called:
(A) Electroscoping.
(B) Electroplating.
(C) Both.
(D) None.

38.Which one is not a source of electric current:
(A) Voltaic cell.
(B) Daniel cell.
(C) Battery.
(D) None.

39.An electrode connected to the negative terminal of a battery is called:
(A) Anode.
(B) Cathode.
(C) Pole.
(D) None.

40.An electrode connected to the positive terminal of a battery is called:
(A) Anode.
(B) Cathode.
(C) Pole.
(D) None.

41.A compound formed by ions is called an …………. Compound.
(A) Metallic.
(B) Ionic.
(C) Covalent.
(D) None.

42.A metal is released in the electrolysis of a salt. At which electrode will it be deposited?
(A) Anode.
(B) Cathode.
(C) Both.
(D) None.

43.What is the full form of 'LED'

44.Does pure water conducts electricity? It not what can we do to make it conducting

45.Name the products formed when electricity passes through distilled water

<2M>

46.What do you understand by the term magnetic effects of an electric current?

47.What do you understand by the term chemical effects of an electric current?

48.What is a conductor? Give two examples.

49.What is an insulator? Give two examples.

50.What do you mean by the term electroplating?

51.Write some applications of the chemical effect of current.

52.What makes LED more useful for testing the flow of current.

53.Why it is dangerous to touch on electrical appliance with a wet hand?

54.A child staying in coastal region tests the drinking water and also the seawater with his tester. He finds that compass needle defects more in the case of sea water. Can you explain the reason?

55.State two applications of electrolysis.

<3M>

56.What is an electrode? What are cathode and anode?

57.What are dangers of electricity?

58.Write some points that should be remember while electroplating.

59.Write some uses of electroplating.

60.List three conditions that help to ensure a smooth and firm deposit during electroplating.

<5M>

61.What is electroplating? How are steel spoons plated with silver? Explain with the help of diagram.

62.An experiment was set as shown below:

""CBSE-Class-8-Science-Chemical-Effects-of-Electric-Current-Assignment-Set-B

(i) Label the parts indicated by arrows in diagrams.
(ii) Will the bulb glow if the sodium chloride is in:
(a) Solid state?
(b) Molten state?
(c) Aqueous state?
Explain your answer. .

63.Describe an activity to show that current flowing through solutions produce a magnetic effect

Question 1. Fill the blanks.

 
(a) Most liquids that conduct electricity are solutions of acids, bases and salts.
 
(b) The passage of an electric current through a solution causes chemical effects.
 
(c) If you pass current through copper sulphate solution, copper gets deposited on the plate connected to the negative terminal of the battery.
 
(d) The process of depositing a layer of any desired metal on another material by means of electricity is called electroplating.
 
Question 2. When the free ends of a tester are dipped into a solution, the magnetic needle shows deflection. Can you explain the reason?
Answer- Yes, because solution is conductor of electricity.
 
Question 3 Name three liquids, which when tested in the manner shown in Fig.14.9 may cause the magnetic needle to deflect.
8th.sci.eng.oct.nov.21.22 3
Answer- Vinegar, Lemon juice and tap water.
 
Question 4. The bulb does not glow in the setup shown in fig. 14.10. List the possible reasons. Explain your answer.
 
 8th.sci.eng.oct.nov.21.22 4
Answer- The bulb may not glow because of the following reasons:
(i) Liquid in the beaker may be non-conducting.
(ii) The battery may be exhausted and does not have sufficient energy to generate electricity.
(iii) The bulb may be fuse.
(iv) Connections may be loose.
 
Question 5. A tester is used to check the conduction of electricity through two liquids. Labelled A and B. it is found that the bulb of the tester glows brightly for liquid A while it glows very dimly for liquid B. you would conclude that
(i) Liquid A is a better conductor than liquid B 
(ii) Liquid B is a better conductor than liquid A
(iii) Both liquids are equally conducting
(iv) Conducting properties of liquid cannot be compared in this manner.
Answer-  Liquid A is a better conductor than liquid B
 
Question 6- Does pure water conduct electricity? If not, what can we do to make it conducting?
Answer- No. Pure water does not conduct electricity. This is because pure water do not have any free ion. Pure water can conduct electricity when a pinch of common salt is added to it, as salt solution is conducting in nature.
 
Question 7. In case of fire, before the firemen use the water hoses, they shut off the main electric supply for the area. Explain why they do this.
Answer- Water usually contains salts and conducts electricity. If the electrical supply is not cut off and firemen come in contact with wet electric switches, electric wires and other electrical appliances, he can get electric shock.
 
Question 8. A child staying in a coastal region tests the drinking water and also the seawater with his tester. He finds that the compass needle deflects more in the case of seawater. Can you explain the reason?
Answer- Water we use for drinking purposes has very less amount of salts dissolved in it while sea water has very high concentration of salts in it. So, compass needle shows more deflection in case of sea water.
 
Question 9. Is it safe for the electrician to carry out electrical repairs outdoors during heavy rain pour? Explain.
Answer- No. It is not safe to repair electrical appliances outdoors during heavy downpour. This is because rain water contains small amounts of acids in it which makes it a conductor of electricity. So, the electrician may get electrical shocks while working outdoors during rain.
 
Question 10- Paheli had heard that rainwater is as good as distilled water. So, she collected some rainwater in a clean glass tumbler and tested it using a tester. To her surprise she found that the compass needle showed deflection. What could be the reason?
Answer- Rain water is said to be pure water. But many impurities and acidic gases get dissolved in the rain water while it falls to the earth through the atmosphere. Due to the presence of these impurities and small amounts of acids in it, the rainwater conducts electricity.
 
Question 11. Prepare a list of objects around you that are electroplated.
Answer- The objects which are electroplated are:
(i) Taps of water connection.
(ii) Parts of bicycle.
(iii) Body of cars, motor cycle and tractors.
(iv) Handles of the doors.
 
Question 12- The process that you saw in Activity 14.7 is used for purification of copper. A thin plate of pure copper and a thick rod of impure copper are used as electrodes. Copper from impure rod is sought to be transferred to the thin copper plate. Which electrode should be attached to the positive terminal of the battery and why?
Answer- The thick rod of impure copper should be attached to the positive terminal of battery. This is because the copper ions of the solution will get deposited on the thin rod and the loss of copper from the solution will be restored from the thick rod to the positive terminal of the battery. Thus, copper from the thick rod could be extracted out..
 
 

CBSE Class 8 Science - Chemical Effects of Electric Current (3)

CBSE Class 8 Science - Chemical Effects of Electric Current (3)

1. Veena has read that some substances are good conductors of electricity where as some are bad conductors. Among the following which substance is good conductor of electricity?

a) Copper
b) Silver
c) Iron
d) All of the above (✓)
 
2. Today Rohit came to know that in the ancient times people used a device to detect direction. What was that device called?
a) Voltmeter
b) Ammeter
c) Magnetic Compass (✓)
d) All of the above
 
3. Manish today read about various effects of electric current. Electric bulb works on which effect of electric current
a) Heating effect (✓)
b) Magnetic effect
c) Chemical effect
d) All of the above
 
4. Neeta's mother today brought gold plated silver jewelry. What is the process of plating one metal on another metal called?
a) Vaporization
b) Electroplating (✓)
c) Distillation
c) All of the above
 
5. Dhruv was very happy to see traffic signals in the city. What kinds of lights are used in traffic signals?
a) Tungsten bulb
b) LED bulb (✓)
c) Neon bulb
d) None of the above
 
6. Meenakshi broke a dry cell today. She got a black colored rod from it. What is this rod called?
a) Electrode (✓)
b) Electrolyte
c) Insulator
d) All of the above
 
7. Heera singh is surprised that the flow of electric current breaks the water into hydrogen and oxygen. Can you tell me that due to which effect of current this happens?
a) Heating effect
b) Chemical effect (✓)
c) Magnetic effect
d) All of the above
 
8. Today Baljinder saw in science lab that lemon juice is good conductor of electricity. Among the following which is good conductor of electricity?
a) Vinegar
b) Tap water
c) Tomato juice
d) All of the above (✓)
 
9. Electricity repair is going on at sewak's house. He saw that handles of electrical repairing tools are made up of plastic. What is the reason for this?
a) Plastic is good conductor of electricity.
b) Plastic is bad conductor of electricity. (✓)
c) Plastic generates electricity.
d) None of the above.
 
10. Pankaj knows that pure water is bad conductor of electricity. If you dissolve salt in water what will happen?
a) Water will become good conductor of electricity (✓)
b) Water will become bad conductor of electricity.
c) Water will neither become good conductor nor bad conductor.
d) None of the above.
 
11. Sanjeev noted that there is layer of another metal on iron vehicles. Why is this done?
a) To prevent rusting.
b) To increase the strength of iron.
c) To make the surface shiny.
d) All of the above. (✓)
 
12. Rupinder and Noor attached one end of a LED bulb with a cell and other with a screwdriver. If screwdriver is made of iron then what will happen if it is attached to the other terminal of cell?
a) Bulb will glow(✓)
b) Bulb will not glow
c) Can't say anything
d) Bulb will blink.
 
13. Robin stood near motorcycle and asked his father that the rim of wheel is made of iron but why is it more shiny then normal iron?
a) Due to more driving
b) Motorcycle is new
c) There is plating of another metal on iron (✓)
d) Can't say anything.
 
14. On passing electricity through copper sulphate solution, copper will deposits on the plate connected to which terminal of battery?
a) Positive terminal
b) Negative terminal (✓)
c) Both terminals
d) None of the both.
 
15. While electroplating of copper which liquid is added to make the copper sulphate solution more conducting?
a) Sulphuric acid (✓)
b) Sodium Hydroxide
c) Sugar solution
d) Kerosene oil
 
16. Out of below given options which is the use of magnetic effect of current?
a) Electroplating
b) Electric Iron
c) Electric Bulb
d) Electric Bell (✓)
 
17. Rajesh's father brought a LED from market. Rajesh noted that one wire of LED is long and another is short. The Long wire is connected to which terminal of battery?
a) Positive terminal (✓)
b) Negative terminal
c) Neither positive nor negative
d) Any terminal
 
18. Pari's father told her that air is bad conductor of electricity. But Pari has seen the lighting moving toward ground very fast in rainy season even though it was not raining at that time. What is then reason for this?
a) Due to low temperature
b) Due to more humidity in air (✓)
c) Due to high wind speed
d) All of the above
 
19. Some articles e.g. some parts of cars, taps and gas burners have plating of chromium on them.Among the given statements which is not correct for chromium?
1. Chromium has shine. 2. Chromium does not corrode. 3. Chromium is very cheap.
a) 1 (✓)
b) 2 (✓)
c) 3
d) All of the above.
 
20. Which object can be used instead of iron nail in given circuit so that flow of current remain uninterrupted?
a) Graphite (✓)
b) Plastic
c) Wood
d) Rubber

Q1. Do liquids also conduct electricity? Name two liquids which conduct electricity & two liquids which do not conduct electricity.

Q2. Name a device which glows even when a weak electric current passes through it.

Q3. Write full form of LED.

Q4. Which effect of electric current is utilized for detecting the flow of current through a solution:

a) When a torch bulb is used?

b) When a compass is used?

Q5. Is it safe for the electrician to carry out electrical repairs outdoors during heavy downpour? Explain.

Q6. When electric current is passed through acidified water, then hydrogen & oxygen are formed. What type of effect of current is illustrated by this statement?

Q7. State some of the characteristics of chemical changes brought about by the chemical effect of electric current.

Q8. Name the metal which is usually electroplated on car parts such as bumpers & bicycle handlebars made of steel.

Q9. An iron key is to be electroplated with copper. Draw a labeled sketch of the experimental set up used for this purpose.

Q10. Name two metals which are usually electroplated on cheaper metals for making jewellery (or ornaments).

Q11. You are required to do electroplating of copper on an iron object. Name the positive electrode (anode) & the electrolyte you will use for this purpose.

Q12. Write a short note on electroplating.

Q13. Why does compass needle show more deflection when you test sea water, compared to ordinary water?

Q14. Name a liquid which when poured in the beaker may cause magnetic needle to deflect. Name the possibilities if a bulb in tester does not glow (it is for sure that liquid is conducting).

Q15. What happens to the needle of a magnetic compass kept nearby when electric current is switched on in a wire? Why does this happen?

Q16. Iron is used in bridges & automobile to provide strength. Which metal is electroplated on iron to protect it from corrosion?

Q17. We should never handle electrical appliances with wet hands or while standing on a wet floor. Why?

Q18. When the free ends of a conductivity tester (made by using a battery connected to a wire wound around a compass) are dipped into the following solution, then in which solution or solutions the compass needle shows deflection. Solutions are: Lemon juice, Vinegar, Tap water, Vegetable oil, milk, Honey.

Q19. Why does an electric bulb glow when a current passes through it?

Fill in the blanks:

1. Distilled water is _____________ of electricity.

2. The dissociation of chemicals into ions due to the passing of electricity through it is the _____________ of electricity.

3. The distilled water becomes _____________ of electricity on dissolving salt in it.

4. _____________ are wires/rods/plates through which electricity enters of leaves an electrolyte.

5. The longer lead of LED is always connected to the positive terminal of the battery.

6. Name two liquids that conduct electricity _____________.

7. The passage of electric current through liquids causes _____________.

8. Coating of _____________ is deposited on iron to protect it from corrosion.

9. What is LED

10. Define Electroplating

11. Name some materials around you which conduct electricity.

12. Name some materials around you which do not conduct electricity.

Chapter 01 Crop Production and Management
CBSE Class 8 Science Crop Production And Management Assignment
Chapter 02 Microorganisms Friend or Foe
CBSE Class 8 Science Micro Organisms Friends and Foe Assignment
Chapter 03 Synthetic Fibres and Plastics
CBSE Class 8 Science Synthetic Fibers And Plastics Assignment
Chapter 04 Materials Metals and Non-Metals
CBSE Class 8 Science Materials Metals And Non Metals Assignment
Chapter 07 Conservation of Plants and Animals
CBSE Class 8 Science Conservation Of Plants And Animals Assignment
Chapter 08 Cell Structure and Functions
CBSE Class 8 Science Cell Structure and Functions Assignment
Chapter 09 Reproduction in Animals
CBSE Class 8 Science Reproduction in Animals Assignment
Chapter 10 Reaching the Age of Adolescence
CBSE Class 8 Science Reaching the age of Adolescence Assignment
Chapter 14 Chemical Effects of Electric Current
CBSE Class 8 Science Chemical Effects of Electric Current Assignment
Chapter 17 Stars and the Solar System
CBSE Class 8 Science Stars and the Solar System Assignment
Chapter 18 Pollution of Air and Water
CBSE Class 8 Science Pollution of Air and Water Assignment
Class 8 Science Revision Assignments
CBSE Class 8 Science Revision Assignment

More Study Material

CBSE Class 8 Science Chapter 14 Chemical Effects Of Electric Current Assignment

We hope you liked the above assignment for Chapter 14 Chemical Effects Of Electric Current which has been designed as per the latest syllabus for Class 8 Science released by CBSE. Students of Class 8 should download and practice the above Assignments for Class 8 Science regularly. We have provided all types of questions like MCQs, short answer questions, objective questions and long answer questions in the Class 8 Science practice sheet in Pdf. All questions have been designed for Science by looking into the pattern of problems asked in previous year examinations. 

Assignment for Science CBSE Class 8 Chapter 14 Chemical Effects Of Electric Current

Our team of expert teachers have referred to NCERT book for Class 8 Science to design the Science Class 8 Assignments. If you practice at least one test paper daily, you will get higher marks in Class 8 exams this year. Daily practice of Science course notes and related study material will help you to clear all your doubts and have stronger understanding of all concepts. You can download all Revision notes for Class 8 Science also from www.studiestoday.com absolutely free of cost.

Chapter 14 Chemical Effects Of Electric Current Assignment Science CBSE Class 8

All questions and their answers for the assignment given above for Class 8 Science have been developed as per the latest curriculum and books issued for the current academic year. The students of Class 8 can rest assured that the best teachers have designed the questions of Science so that you are able to revise the entire syllabus if you do the assignments. Lot of MCQ questions for Class 8 Science have also been given in the worksheets and assignments for regular use. All study material for Class 8 Science students have been given on studiestoday.

Chapter 14 Chemical Effects Of Electric Current Assignment CBSE Class 8 Science

Regular assignment practice helps to get a more comprehensive understanding of Chapter 14 Chemical Effects Of Electric Current concepts. Assignments play a crucial role in understanding Chapter 14 Chemical Effects Of Electric Current in CBSE Class 8. Students can download all the assignments of the same chapter in Class 8 Science in Pdf format. You can print them or read them online on your computer or mobile.

CBSE Science Class 8 Chapter 14 Chemical Effects Of Electric Current Assignment

CBSE Class 8 Science latest books have been used for coming up with the latest questions and solutions for the above assignment. If you have revised all concepts relating to Chapter 14 Chemical Effects Of Electric Current then you should attempt all questions given in the test sheets above. We have also provided lot of Worksheets for Class 8 Science which you can use to further make your self stronger in Science

Where can I download in PDF assignments for CBSE Class 8 Science Chapter 14 Chemical Effects Of Electric Current

You can download free Pdf assignments for CBSE Class 8 Science Chapter 14 Chemical Effects Of Electric Current from StudiesToday.com

The assignments for Chapter 14 Chemical Effects Of Electric Current Class 8 Science for have been made based on which syllabus

The Chapter 14 Chemical Effects Of Electric Current Class 8 Science Assignments have been designed based on latest CBSE syllabus for Class 8 Science issued for the current academic year

Can I download and print these printable assignments for Science Chapter 14 Chemical Effects Of Electric Current Class 8

Yes, These printable assignments for Chapter 14 Chemical Effects Of Electric Current Class 8 Science are free to download and print

How many topics are covered in Chapter 14 Chemical Effects Of Electric Current Science assignments for Class 8

All topics given in Chapter 14 Chemical Effects Of Electric Current Science Class 8 Book for the current academic year have been covered in the given assignment

Is there any charge for this assignment for Chapter 14 Chemical Effects Of Electric Current Science Class 8

No, all Printable Assignments for Chapter 14 Chemical Effects Of Electric Current Class 8 Science have been given for free and can be downloaded in Pdf format

How can I download the printable test assignments for Chapter 14 Chemical Effects Of Electric Current Science Class 8

Just click on the View or Download button below, then another window with the Pdf will be visible, just click on the Pdf icon to download the free assignments for Chapter 14 Chemical Effects Of Electric Current Class 8 Science

Are these assignments available for all chapters in Class 8 Science

Yes, apart from Science you can download free assignments for all subjects in Class 8

Can I download solved assignments for Chapter 14 Chemical Effects Of Electric Current CBSE Class 8 Science

Our team of expert teachers at studiestoday.com have provided all answers for the practice questions which have been given in Class 8 Science Chapter 14 Chemical Effects Of Electric Current assignments