CBSE Class 8 Science NSO Olympiad MCQs with Answers Set R

MENTAL ABILITY

Question. There are six houses in a row. Mr. Lal has Mr. Bhasin and Mr. Sachdeva as neighbours. Mr. Bhatia has Mr. Gupta and Mr. Sharma as neighbours. Mr. Gupta's house is not next to Mr. Bhasin or Mr. Sachdeva and Mr. Sharma do not live next to Mr. Sachdeva. Who are Mr. Bhasin's next door neighbours?
(A) Mr. Lal and Mr. Bhasin
(B) Mr. Lal and Mr. Sachdeva
(C) Mr. Sharma and Mr. Lal
(D) Only Mr. Lal
Answer : C

Question. If x^a = y^b = z^c and y² = zx, then the value of 1/a + 1/c is ________.
(A) b/2
(B) c/2
(C) 2/b
(D) 2a
Answer : C

Question. If (a² + b²)³ = (a³ + b³)² and ab ≠ 0, then (a/b + b/a) is equal to _______.
(A) a⁶+b⁶/a³b³
(B) 64/729
(C) 1
(D) a⁶+a³+b³+b⁶/a²b⁴+a⁴b²
Answer : B

Question. Choose the correct water image of the given words/numbers from amongst the options.

Answer : A

Question. Select a figure from the options which will continue the series established by the Problem Figures.

Answer : D

Question. In a bangle shop, if the shopkeeper displays the bangles in the form of a square, he is left with 38 bangles. If he wants to increase the size of square by one unit each side of the square he found that 25 bangles fall short of in completing the square. The actual number of bangles which he had with him in the shop was _______.
(A) 1690
(B) 999
(C) 538
(D) Can't be determined
Answer : B

Question. PQRS is a square, 4 equal circles are just touching each other whose centres are the vertices P, Q, R and S of the square. What is the ratio of the shaded to the unshaded area within square?

(A) 8/11
(B) 3/11
(C) 5/11
(D) 6/11
Answer : B

Question. ₹ 100000 was invested by Mohan in a fixed deposit @ 10% per annum at CI. However, every year he was to pay 20% tax on the compound interest. How much money does Mohan has after 3 years ?
(A) ₹ 128414
(B) ₹ 108000
(C) ₹ 126079.2
(D) None of these
Answer : D

Question. In an army camp, there are 800 soldiers. There is enough food for them for 60 days. If 400 more soldiers arrive at the camp, how many days will the food last?
(A) 40 days
(B) 35 days
(C) 45 days
(D) 50 days
Answer : A

Question. The line graph shows the amount of electricity used by Mohit for the first 6 months of last year.
The electricity used is charged at the rate of ₹ 1.5 per kWh for the first 400 kWh and ₹ 0.8 per kWh for usage beyond 400 kWh. An additional 12% of the amount charged is to be paid as tax. How much did Mohit pay for the electricity used in March ?

(A) ₹ 698.8
(B) ₹ 403.2
(C) ₹ 700.4
(D) ₹ 716.8
Answer : D

Question. The ratio between curved surface area and total surface area of a cylinder is 2 : 3. If the total surface area be 924 cm2, find the volume of the cylinder.
(A) 2156 cm³
(B) 1256 cm³
(C) 1265 cm³
(D) 1862 cm³
Answer : A

Question. A scientific calculator is available at Universal Shop in Hazratganz at 20% discount and the same is available at only 15% discount at Bhootnath Market. Pooja has just sufficient amount of ₹ 800 to purchase it at Universal Shop, Hazratganz. What is the amount that Pooja has less than the required amount to purchase it at Bhootnath?
(A) ₹ 70
(B) ₹ 50
(C) ₹ 100
(D) Data insufficient
Answer : B

Question. Factorise 25(x + 2y)² – 36(2x – 5y)².

(A) (4x – 2y) (3x + 5y)
(B) (17 x – 20y) (40 y – 7x)
(C) (17x – 4y) (31x – 4y)
(D) (2x – y) (x +y)
Answer : B

Question. How many lines of symmetry does the figure have?
(A) 1
(B) 3
(C) 2
(D) 0
Answer : D

Question. Two slips of papers are drawn from a hat having four slips labelled with 7, 8, 9 and 10. What is the probability of obtaining 7 and then 9 (the first slip is replaced before drawing the second slip)?
(A) 1/16
(B) 1/8
(C) 1/4
(D) 3/5
Answer : A

SCIENCE

Question. The two ends of a spring are displaced along the length of the spring. All displacements have equal magnitudes. In which case the tension or compression in the spring will have maximum magnitude?
(A) The right end is displaced towards right and the left end towards left.
(B) Both ends are displaced towards right.
(C) Both ends are displaced towards left. (D) None of these
Answer : A

Question. Read the given statements and choose the correct option.
Statement 1 : When static friction acts, there is no loss of mechanical energy.
Statement 2 : When kinetic friction acts between two bodies, there is loss of mechanical energy.
(A) Both statements 1 and 2 are true and statement 2 is the correct explanation of statement 1.
(B) Both statements 1 and 2 are true, but statement 2 is not the correct explanation of statement 1.
(C) Statement 1 is true but statement 2 is false.
(D) Statement 1 is false but statement 2 is true.
Answer : B

Question. Four metal cans are identical except for the colour and texture of their outer surfaces. 100 cm3 of water at 70°C is poured into each can. Which can cool most rapidly?

(A) P
(B) Q
(C) R
(D) S
Answer : A

Question. A student uses a converging lens to produce an enlarged virtual image of a scale she wishes to read accurately. The focal length of the lens is 10 cm. What is a suitable distance between the scale and the lens?
(A) 8 cm
(B) 10 cm
(C) 15 cm
(D) 20 cm
Answer : A

Question. A Jogger runs in a straight line, with a magnitude of average velocity of 5.00 m s^–1 for 4.00 minute and then with a magnitude of average velocity of 4.00 m s^–1 for 3.00 minute. What is the magnitude of the final displacement from her initial position?
(A) 1.92 × 10³ m
(B) 2.56 × 10³ m
(C) 3.19 × 10³ m
(D) 0 m
Answer : A

Question. A bottle is filled with water. A cap is put on the bottle and it is turned upside down. There is no air inside the bottle. The area of the cap in contact with the water is 4.0 × 10^–4 m². The density of water is 1000 kg m^–3 and the gravitational field strength is 10 N kg^–1. The water produces a force on the cap.
What is the value of this force?

(A) 0.075 N
(B) 0.12 N
(C) 1.2 N
(D) 13 N
Answer : C

Question. Which of the following scales are not linear in nature?
(i) Decibel (ii) Richter (iii) Meter
(A) (i) only
(B) (ii) and (iii)
(C) (ii) only
(D) (i) and (ii)
Answer : D

Question. P and Q are two blocks of different metals. They have the same volume but block P has twice the mass of block Q. When given identical quantities of energy, their temperatures rise by the same amount. Which one of the following statements is true?
(A) The density of P is half that of Q.
(B) The density of P is the same as that of Q.
(C) The specific heat capacity of P is half that of Q.
(D) The specific heat capacity of P is the same as that of Q.
Answer : C

Question. Frictional forces do not exist ___________.
(A) On high mountains
(B) In water
(C) In the atmosphere
(D) In space
Answer : D

Question. All the following statements about instantaneous speed is false except for ______.
(A) Instantaneous speed is, when an object moves with the same speed throughout the journey.
(B) Instantaneous speed is measured in cm3 h–1.
(C) Instantaneous speed is the average speed over a certain distance.
(D) Instantaneous speed is the speed at any instant of time during the journey.
Answer : D

Question. A magnet is moved into the coil of wire as shown, there is a small reading on the sensitive meter.
Which change would increase the size of the reading?

(A) Moving the south pole in
(B) Pulling the magnet out
(C) Pushing the magnet in faster
(D) Unwinding some of the turns of wire
Answer : D

Question. The dipper in a ripple tank vibrates at a frequency of 4.0 Hz and the resulting wave pattern is photographed. The distance between the two crests shown is 20 cm. What is the speed of the wave?

(A) 4 cm s^–1
(B) 5 cm s^–1
(C) 16 cm s^–1
(D) 20 cm s^–1
Answer : C

Question. What is the refractive index of a medium?
(A) The ratio of the speed of light in air to the speed of light in the medium
(B) The ratio of the speed of light in the medium to the speed of light in air
(C) The ratio of the speed of light in the medium to the speed of light in vacuum
(D) The ratio of the speed of light in vacuum to the speed of light in the medium
Answer : D

Question. There is a hole at the bottom of a cubic container which contains oil inside. The oil flows out smoothly and is collected by a measuring cylinder. 54 cm³ of liquid is collected in 3 minutes time.
What is the average rate of fluid flow?
(A) 18 cm³ s^–1
(B) 18000 cm³ s^–1
(C) 0.3 cm³ min^–1
(D) 0.3 cm³ s^–1
Answer : D

Question. Amit carried a box up the flight of stairs shown in the diagram.

He did 150 J of work in the process. The mass of the box is _____.
(A) 7.5 kg
(B) 75 kg
(C) 15 kg
(D) 150 kg
Answer : C

Question. Identify the fibres, P, Q and R using the given hints.
P. It does not get wrinkled easily, remains crisp and is easy to wash.
Q. It was the first fully synthetic fibre.
R. Although it is obtained from a natural source, yet it is a man-made fibre.
(A) P - Rayon, Q - Polythene, R - Terylene
(B) P - Polyester, Q - Nylon, R - Rayon
(C) P - Nylon, Q - Polythene, R - Bakelite
(D) P - Melamine, Q - Nylon, R - Polyester
Answer : B

Question. Study the given flowchart and identify K, L, M and N respectively.

(A) Carbon dioxide, nitrogen oxides, methane, sulphur dioxide
(B) Carbon monoxide, methane, sulphur dioxide, nitrogen oxides
(C) Methane, carbon monoxide, carbon dioxide, sulphur dioxide
(D) Sulphur dioxide, carbon monoxide, methane, nitrogen oxides
Answer : B

Question. Rakshit has three test tubes containing ZnSO₄, Al₂(SO₄)₃ and FeSO₄ solutions. He dropped magnesium pieces into all the three test tubes. Choose the option with the correct match.

Answer : S

Question. Kanchan carried out an experiment in which she put one end of four rods, P, Q, R and S made up of iron, copper, carbon and zinc respectively into a container filled with boiling water. After 15 minutes, she recorded the temperature at the undipped ends of all rods.
Which rod will show the lowest temperature?
(A) P
(B) Q
(C) R
(D) S
Answer : C

Question. Kavita wrote two sentences about calorific value of fuels.
(i) The amount of heat energy required by 1 kg of a fuel to reach its ignition temperature for the complete combustion is called its calorific value.
(ii) It is expressed in a unit called kilojoule per kg (kJ/kg).
Choose the correct sentence(s).
(A) (i)
(B) (ii)
(C) Both (i) and (ii)
(D) None of these
Answer : B

Question. Study the given flowchart carefully. K, L, P and Q plastics are

Answer : D

Question. Choose the incorrect statement among the following.
(A) Many useful substances are obtained from petroleum and natural gas. These are termed as 'petrochemicals'.
(B) Hydrogen gas obtained from natural gas, is used in the production of fertilizers.
(C) Due to the great commercial importance of petroleum, it is also called 'black gold'.
(D) Natural gas is stored under low pressure as compressed natural gas (CNG).
Answer : D

Question. Which of the following is a false description about different zones of a flame?

(A) W - It is non-luminous, the hottest part and contains unburnt carbon particles.
(B) X - It is luminous and involves partial combustion.
(C) Y - It is least hot and dark.
(D) Z - It is blue zone where carbon monoxide burns.
Answer : A

Question. To maintain soil fertility, nutrient replenishment of soil is essential. Common methods of adding nutrients to soil are given in the box below.
P = Field fallow Q = Green manure R = Fertilizers S = Organic wastes
Which of the following statements is incorrect regarding this ?
(A) P is not best suited because it leaves a field economically useless for a year or two.
(B) R increases productivity readily but prove to be environmental hazard in long run.
(C) S can cause spread of diseases due to pathogenic cysts present in it.
(D) Q are green plants that are ploughed back into soil to supply specific nutrients in desired ratio.
Answer : D

Question. Which of the following Petri-dishes is most likely to contain a Lactobacillus colony?

Answer : C

Question. Analyze the given table regarding the condition of the fields and other requirements and identify the irrigation systems best suited for the two farmers Sohan and Harish.

            Sohan                         Harish
(A) Sprinkler system            Drip irrigation
(B) Drip irrigation                 Sprinkler system
(C) Surface irrigation           Drip irrigation
(D) Drip irrigation                 Surface irrigation
Answer : D

Question. The given graph shows three methods of food preservation P, Q and R, which work on the principle that at particular temperature the growth of food spoiling microbes is adversely affected.
Which of the following options is correct regarding this?

(A) P is ultra-heat treatment in which food is heat sterilized and then stored in microbe-free container.
(B) Q is pasteurization which preserves food for few days if stored in a cool place.
(C) R is freeze preservation which preserves food for longer when it is kept frozen.
(D) All of these
Answer : D

Question. Three friends made the following statements.
Sunil : Indian giant squirrel is found only in India. It is an X species.
Shruti : Eichhornia now seen growing widely in ponds and lakes was naturally not found in India. It is an Y species.
Priyanka : Indian rhinoceros will no longer be seen on earth if not conserved. It is an Z species.
Identify the terms X, Y and Z and select the correct option.
(A) X - Endemic; Y - Extinct; Z - Endangered
(B) X - Epidemic; Y - Exotic; Z - Extinct
(C) X - Endemic; Y - Exotic; Z - Endangered
(D) X - Epidemic; Y - Exotic; Z - Endangered
Answer : C

Question. Shashank performed an experiment where he took two unicellular organisms X and Y which reproduce by binary fission. By using a micropipette (a scientific tool), he interchanged nuclei of two of the daughter organisms just after cell division as shown in the figure.

Which of the following is the most likely result of his experiment?
(A) Organism Q will show characteristics of parent organism X.
(B) Organisms P and S will show similar characteristics.
(C) Organism R will show characteristics of organism X.
(D) Organisms P and Q will show similar characteristics.
Answer : B

Question. The given graph represents the changes in thickening of uterine wall in two women X and Y over a period of one month. What should be the correct conclusion regarding this?

(A) Woman X has conceived.
(B) Woman Y is undergoing menopause.
(C) Both women X and Y will undergo menarche in the next month.
(D) Both (A) and (B)
Answer : A

Question. Refer the given Venn diagram. Which among the following would most likely be X?

(A) Acid rain
(B) Vehicular exhausts
(C) Factory discharge
(D) Agricultural runoff water
Answer : C

Question. Refer the given figure of a typical cell and select the option that incorrectly matches the cell modification with its function? 

(A) In a free moving cell like WBC, structure P will be more elastic and pliable.
(B) A cell that is extensively involved in secreting substances such as enzymes, structures R and S will be highly developed.
(C) A cell that is extensively involved in protein synthesis, will have large number of structure Q.
(D) A cell that needs lots of energy will have abundant number of structure T.
Answer : C

Question. Read the given statements.
(i) IVF is a treatment for infertility when a woman is able to produce ovum however, problems of the Fallopian tube make fertilization difficult.
(ii) Asexual reproduction is a rapid and easier method of multiplication.
(iii) Unicelled organisms reproducing by binary fission are referred to as 'immortals' because actual death of the parent does not occur.
(iv) Metamorphosis is the transformation of an adult animal to larval form.
Which of the given statements are correct?
(A) (ii) and (iv)
(B) (i), (ii), (iii) and (iv)
(C) (i), (ii) and (iii)
(D) (ii), (iii) and (iv)
Answer : C

Question. Read the given statements and select the correct option.
Statement 1 : Diabetes is characterized by inefficient glucose metabolism.
Statement 2 : In diabetes, malfunctioning or malsecretion of insulin affects glucose metabolism.
(A) Both statements 1 and 2 are correct and statement 2 is the correct explanation of statement 1.
(B) Both statements 1 and 2 are correct but statement 2 is not the correct explanation of statement 1.
(C) Statement 1 is correct but statement 2 is incorrect.
(D) Both statements 1 and 2 are incorrect.
Answer : A

Question. Five chemical factories P, Q, R, S and T are located in different cities along a river bank. Municipal officer, in order to estimate the pollution caused by these factories, counted the number of fishes present at the places where these factories discharged their wastes into the river. A graph as shown here, is plotted based on the observations.
What can be inferred from the graph?

(A) Factory R dumps the least toxic wastes in the river.
(B) Factory P dumps its waste into river after removing toxic wastes.
(C) Fishes are maximally harmed by the toxic wastes of factory Q.
(D) Factory T dumps the most toxic wastes in the river.
Answer : D