CBSE Class 8 Science NSO Olympiad MCQs with Answers Set M

SCIENCE

Question. The displacement-time graph of two notes I and II are shown.
Which note is louder and which note has a higher pitch?

    Louder       Higher pitch
A.    I                     I
B.    I                     II
C.    II                    I
D.    II                    II
Answer : B

Question. Match column-I with column-II and select the correct option from the codes given below.
     Column-I                     Column-II
(a) Polaris                  (i) Laghu saptarishi
(b) Big dipper            (ii) Dhruv tara
(c) Orion                   (iii) Vrihat saptarishi
(d) Ursa minor          (iv) Mriga
A. (a)-(ii), (b)-(iii), (c)-(iv), (d)-(i)
B. (a)-(ii), (b)-(i), (c)-(iv), (d)-(iii)
C. (a)-(iv), (b)-(ii), (c)-(iii), (d)-(i)
D. (a)-(i), (b)-(ii), (c)-(iii), (d)-(iv)
Answer : A

Question. A charged rod is held close to one side of a metal ball and the other side is earthed. Which diagram correctly shows the charge distribution?

Answer : B

Question. Read the given statements and select the correct option.
Statement 1 : Mountaineers often encounter the problem of nose bleeding when they reach high altitudes.
Statement 2 : The blood pressure of their body becomes much less than the atmospheric pressure, making the blood vessels burst.
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. Both statements 1 and 2 are false.
Answer : C

Question. A lens forms a blurred image of an object on a screen.

How can the image be focused on the screen?
A. Move the screen away from the lens and object.
B. Use a brighter object at the same position.
C. Use a lens of longer focal length at the same position.
D. None of these.
Answer : C

Question. A 12 m long uniform bridge weighing 100000 N is being supported at the two ends. A lorry weighing 30000 N is parked at the 4 m mark as shown in the figure. What are the forces acting on the bridge by support A and support B respectively?

    Support A            Support B
A. 70000 N                60000 N
B. 60000 N                70000 N
C. 65000 N                65000 N
D. 90000 N                40000 N
Answer : A

Question. Which of the following options is true when a multi-plug adapter is used to connect many appliances to the same socket?
A. The current drawn from the mains gets higher and overheating may occur.
B. The voltage across the live and neutral wires increases and overheating may occur.
C. The flow of the current will be slowed down and the power to each appliance will reduced.
D. The appliances will be damaged due to the higher current that flows through each appliance.
Answer : A

Question. The diagram shows a ray PQR travelling through a glass slab.
Which of the following options gives the correct name for all three parts of the ray?

           P                           Q                             R
A. Incident ray         Emergent ray        Refracted ray
B. Incident ray         Refracted ray       Emergent ray
C. Emergent ray      Incident ray          Refracted ray
D. Emergent ray      Refracted ray       Incident ray
Answer : B

Question. Which of the following statements are incorrect?
(i) It is easier to roll than to slide some heavy object over another fixed object.
(ii) If there is less friction between the car tyres and road, then the car can move forward very smoothly without skidding.
(iii) Friction helps a person to climb a tree or a pole.
(iv) Friction helps us to light a matchstick.
(v) Ball bearings are designed to increase friction between moving parts of machines.
A. (ii) and (iii) only
B. (i), (ii), (iii) and (iv) only
C. (iii), (iv) and (v) only
D. (ii) and (v) only
Answer : D

Question. Read the given statements and select the correct option.
Statement 1 : When a sitar string is plucked lightly then it produces a feeble sound.
Statement 2 : Loudness of sound depends on the amplitude of vibrations of vibrating object.
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. Both statements 1 and 2 are false.
Answer : A

Question. Man X is standing in front of a plane mirror while man Y is running towards him from behind. If the man Y is running at a speed of 1 m s–1, how many metres nearer does the man Y seem to be away from man X after 5 seconds?

A. 7 m
B. 5 m
C. 6 m
D. 10 m
Answer : B

Question. Which of the following statements are incorrect?
(i) In an LED, the longer lead is anode, which is always connected to the negative terminal of the battery.
(ii) If electrodes are immersed in water, and current is passed, oxygen bubbles are formed on the electrode connected to negative terminal of the battery.
(iii) Most liquids that conduct electricity are solutions of acids, bases and salts.
(iv) Tin cans, used for storing food are made by electroplating tin on iron, because tin is less reactive than iron.
A. (i) and (ii) only
B. (iii) and (iv) only
C. (ii) and (iv) only
D. (ii) and (iii) only
Answer : A

Question. An earthquake of magnitude 8 on Richter scale is how many times more destructive than an earthquake of magnitude 6 ?
A. 100
B. 1000
C. 1500
D. 2000
Answer : B

Question. The diagram shows two plane mirrors inclined at an angle of 50º to each other. A ray is incident on mirror 1, then the deviation x (shown in the figure) of ray after two reflections is

A. 50°
B. 100°
C. 120°
D. 150°
Answer : B

Question. In an experiment to measure the speed of sound in air, Binny stands 40 m from a wall and claps loudly.
At the instant she hears the echo, she claps again. She does this activity 25 times in 5 s. Which calculation gives the speed of sound (in ms–1) in air?
A. 25x2x40/5
B. 5/25x40
C. 25x2x5/40
D. 25x40/5
Answer : A

Question. Which graph shows the relationship between the pressure and volume of a fixed mass of a gas in a container at constant temperature?

Answer : C

Question. Read the given statements and select the correct option.
Statement 1 : Sound travels faster on a rainy day than on a dry day.
Statement 2 : The velocity of sound depends upon the medium.
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 : A

Question. Ria, a class 8 student wanted to compare the water absorption capacity of different fabrics. She held the cloth tightly on a bangle and added water dropwise
in the centre of the ring as shown in the figure.

Then, she counted the number of drops till the soaked water touched the ring and recorded her observations in the given table.
Fibres P, Q, R and S could be respectively

A. Cotton, silk, nylon and wool
B. Silk, nylon, cotton and wool
C. Wool, nylon, silk and cotton
D. Wool, cotton, nylon and silk.
Answer : A

Question. The given table shows some properties of four substances P, Q, R and S

Study the table carefully and identify P, Q, R and S

Answer : C

Question. Fill in the blanks with the most appropriate option.
‘W’ is a very reactive metal, reacts vigorously with oxygen and water therefore, stored in (1) . ‘X’ is a non-metal, soft and dull and, forms (2) oxides with oxygen. ‘Y’ is very reactive (3) , catches fire if exposed to air, therefore, stored in water. ‘Z’ does not react with dilute hydrochloric acid even on heating but it reacts with sulphuric acid. When it is exposed to moist air for long, it acquires a dull (4) coating.
A. 1-Water, 2-Basic, 3-Metal, 4-Reddish brown
B. 1-Kerosene, 2-Acidic, 3-Metal, 4-Red
C. 1-Kerosene, 2-Acidic, 3-Non-metal, 4-Green
D. 1-Water, 2-Basic, 3-Non-metal, 4-Green
Answer : C

Question. Read the given paragraph carefully and fill in the blanks by choosing the appropriate option.
(i) is a thick dark, strong smelling liquid found deep in the earth. Unrefined (i) is called (ii) and (iii) gets collected over (i) inside the earth. During fractional distillation of (i), the fraction with (iv) boiling point condenses in the uppermost region and uncondensed (v) comes out of the fractionating tower.

Answer : C

Question. Which of the following statements are correct?
I. Substance which undergoes spontaneous combustion have ignition temperature higher than the room temperature.
II. Respiration is a special combustion reaction at body temperature.
III. Formation of rust is an example of slow combustion.
IV. Combustion is an exothermic reaction.
A. I and II only
B. II and IV only
C. I, II and IV only
D. II, III and IV only
Answer : D

Question. Observe the given figure carefully and choose the incorrect statement.

A. Naphthalene balls are obtained from X.
B. Y is used as a source of heat.
C. Z is used for making fertilizers.
D. No residue is left behind in test tube A after all the gases have stopped being evolved.
Answer : D

Question. Rohan burned a substance X and collected the evolved vapours in a test tube making sure that they do not escape. Then he added small amount of water to the test tube. The solution so formed turned blue litmus red.
Rahul burned a substance Y, collected the white ash formed and dissolved it in water. The solution so formed turned red litmus blue. Substances X and Y could be respectively
A. P and Mg
B. Ca and P
C. Mg and S
D. S and Mg
Answer : D

Question. Match the column I with column II and mark the correct option from the given codes.
       Column I                            Column II
(a) Polyester               (i) Prepared by using wood pulp
(b) Teflon                    (ii) Used for making parachute and stockings
(c) Rayon                   (iii) Used for making non-stick cookwares
(d) Nylon                    (iv) Fabrics do not wrinkle easily
A. (a)-(iii), (b)-(iv), (c)-(i), (d)-(ii)
B. (a)-(iv), (b)-(iii), (c)-(i), (d)-(ii)
C. (a)-(iv), (b)-(iii), (c)-(ii), (d)-(i)
D. (a)-(i), (b)-(ii), (c)-(iii), (d)-(iv)
Answer : B

Question. Four metals K, L, M and N are added to the following solutions one by one. The observations made are as follows :

Which of the given solutions can be easily stored in a container made up of any of these metals?

A. FeSO₄
B. CuSO₄
C. ZnSO₄
D. AgNO₃
Answer : C

Question. Which of the following statements about plastics are true?
(i) All plastics are thermosetting and have linear arrangement of monomers.
(ii) Plastics with crosslinked monomers are also known.
(iii) Most of the thermoplastics can be recycled.
(iv) Plastics do not react with water and air.
A. (i) and (ii)
B. (i), (iii) and (iv)
C. (i) and (iv)
D. (ii), (iii) and (iv)
Answer : D

Question. Sahil performed an experiment in the lab to test whether a substance produces flame on burning or not. He recorded his observations in the given table

The correct observations are
A. 1, 2 and 5
B. 1, 4 and 5
C. 1, 3 and 5
D. 1, 3 and 4
Answer : A

Question. Refer to the given Venn diagram and select the correct option regarding characteristics P and Q.

A. P - Protection of both flora and fauna
Q - Limited human activities allowed
B. P - Protection of fauna only
Q - No human activities allowed
C. P - Private ownership is permitted
Q - Protection of both flora and fauna
D. P - Areas well demarcated into core, buffer and transition zones
Q - Areas around places of worship held in high esteem by tribal communities
Answer : A

Question. Refer to the given flow chart and select the correct statement regarding it.

A. W causes typhoid in humans and leaf curl disease in plants.
B. X causes malaria in humans and yellow vein mosaic disease in plants.
C. Y causes athlete's foot in humans and late blight in potatoes.
D. Z causes leprosy in humans and citrus canker in plants.
Answer : C

Question. Refer to the given relationships and select the option that correctly completes each one of them.
I. Kanha National Park : Madhya Pradesh : P
II. Kaundinya Wildlife Sanctuary : Q : Elephants
III. R : Assam : One horned rhinoceros

Answer : B

Question. Refer to the given figure and select the incorrect statement regarding P, Q, R and S.

A. P is rich in RNA and proteins.
B. Q is rich in DNA and can occur in condensed form also.
C. R is opaque, semifluid substance that lacks proteins.
D. S is selectively permeable and separates R from cytoplasm.
Answer : C

Question. In a village, farmers started using DDT as pesticide in their crop fields, located nearby river.
Given table shows the concentration of DDT as found in tissues of various organisms present in that river.

Which of the following option shows the correct order in which these organisms are linked in a food chain?
A. I → III → V → II → IV
B. I → V → III → II → IV
C. IV → II → III → V → I
D. II → IV → V → III → I
Answer : B

Question. Refer to the given figures and select the incorrect statement regarding them.

A. Z is an organ that receives the sperm which fertilises ovum in X.
B. Secretions of both Q and Y help in development of male and female gametes, respectively.
C. Both P and W secrete hormones that control development of secondary sexual characters in males and females, respectively.
D. R is an erectile organ that releases its contents into Z which also serves as birth canal during parturition.
Answer : B

Question. Refer to the given graph.
Which of the following could be X?

A. Temperature
B. Greenhouse effect
C. Sea level
D. All of these
Answer : D

Question. The given flow chart shows the sequence of various steps involved in crop production. Identify the missing steps and select the incorrect statements regarding them. Preparation of soil → Sowing of seeds → Applying manure and fertilisers → P → Q → Protection from pest → R → S → T → Storage of grains
I. Process P helps in the intake of minerals by the plant.
II. Process Q can also be done before sowing of seeds.
III. Process Q is usually done manually using khurpi, etc. when performed after P.
IV. After R, the left over in the field can be used as manure by farmers.
V. T can be done using a thresher or a combine.
A. I and II only
B. II and III only
C. IV and V only
D. V only
Answer : D

Question. Refer to the given graph and select the correct option regarding it.

A. Liver is the main organ responsible for maintaining blood glucose concentration.
B. At point X adrenaline is secreted by pancreas.
C. At point Y insulin is secreted by pancreas.
D. Glucose concentration in blood keeps fluctuating throughout the day.
Answer : D

Question. Refer to the given table and select the option that correctly identifies W, X, Y and Z.

Answer : B

Question. Match the columns and select correct option from the given codes.

A. a-(iii)-(p); b-(i)-(t); c-(v)-(q); d-(ii)-(r); e-(iv)-(s)
B. a-(iv)-(p); b-(i)-(t); c-(v)-(r); d-(ii)-(q); e-(iii)-(s)
C. a-(i)-(t); b-(iii)-(p); c-(iv)-(r); d-(ii)-(q); e-(v)-(s)
D. a-(i)-(p); b-(iii)-(t); c-(v)-(q); d-(iv)-(s); e-(ii)-(r)
Answer : A

Question. Read the given statements.
(i) A woman who is unable to produce ovum or has problems in the Fallopian tube making fertilisation difficult can opt for IVF.
(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) only
B. (i), (ii), (iii) and (iv)
C. (i), (ii) and (iii) only
D. (ii), (iii) and (iv) only
Answer : C

Question. Refer to the given graph showing thickness of the uterine layer of an adult woman during a period of time.

Thickness of uterine layer (arbitrary units)
Which of the following occurs if the curve continues along the dotted line?
A. Corpus luteum has degenerated resulting in formation of blood clot.
B. An embryo has been embedded in the uterine layer.
C. The amount of menstrual flow has increased.
D. Two ova are simultaneously released from the ovary.
Answer : B

Question. Read the given statements and select the correct option.
Statement 1 : An increase in the concentration of greenhouse gases in the atmosphere would cause more heat to be retained by the atmosphere leading to global warming.
Statement 2 : Greenhouse gases, e.g., CO2, CH4 etc., reflect back the infrared radiations reflected by the earth’s surface.
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 and statement 2 is false.
D. Statement 2 is true and statement 1 is false.
Answer : A

Question. Identify P, Q, R and S in the given flow chart and select the correct option.

A. P-Pituitary gland, Q-Thyroid
B. R-Hypothalamus, S-Insulin
C. P-Hypothalamus, R-Adrenaline
D. Q-TSH, S-Thyroxine
Answer : D

Question. The manufacture of bread, beer and wine involves alcoholic fermentation of glucose to ethanol by yeast.
Which of the following statements concerning this process is incorrect?
A. Yeast carries out fermentation because yeast cells lack mitochondria.
B. For every molecule of ethanol produced, one molecule of CO2 evolves.
C. During fermentation by yeast, pyruvic acid is first converted to acetaldehyde which finally converts to ethanol.
D. Pyruvate decarboxylase and alcohol dehydrogenase play key role in this process.
Answer : A

Question. Mrs. Mehra, who is 32 years old, underwent a surgery to get her oviducts removed after having girl. Now, she wants to have another baby. Do you think she can have another baby?
A. Yes, she can have another baby as her ovaries are still functional to produce eggs.
B. No, she cannot have another baby because fertilisation of egg takes place in the oviduct.
C. Yes, she can have another baby because the surgery can be reversed.
D. No, she cannot have another baby as the hormones associated with the oviduct will not be present
Answer : B

ACHIEVERS SECTION

Question. Ms. Abha, a science teacher demonstrated three experiments in lab as follows

Which of the following observations and inferences drawn is/are correct?
A. I and II only
B. II and III only
C. III only
D. I only
Answer : B

Direction (Q. No a and b ) : Refer to the given passage and answer the following questions.
Two concrete rectangular blocks 1 and 2 have dimensions as shown in figures. Standing on one of its faces as shown, the pressure exerted by block 1 is P. Both the blocks are made of same material.

Question a. Find the value of P, if weight of the block 1 is 5 N, and the value of x, y and z are 2 cm, 6 cm and 8 cm respectively.
A. 3125 N m^–2
B. 4167 N m^–2
C. 1389 N m^–2
D. 1042 N m^–2
Answer : B

Question b. What is the pressure exerted by block 2 when it stands on the face as shown in figure ?
A. (x/2z)P
B. (x/z)P
C. (x/y)P
D. (2y/z)P
Answer : D

Question. Refer to the given statements and select the option that corrects underlined word wherever necessary.
I. Endoplasmic reticulum is responsible for packaging and transporting products of glandular cells.
II. Vacuoles contain chemical substances that digest intra and extracellular materials.
III. Ribosomes are membranous structures found scattered in the cytoplasm of all cells.
IV. Mitochondria are absent in mature mammalian red blood cells.
A. Endoplasmic reticulum in I must be replaced by Golgi apparatus whereas membranous in III must be replaced by non-membranous.
B. Vacuoles in II must be replaced by Centrosomes whereas membranous in III should not be replaced as it is correctly mentioned.
C. Red blood cells in IV must be replaced by sperms.
D. Endoplasmic reticulum in I must be replaced by Peroxisome whereas Vacuoles in II must be replaced by Lysosomes.
Answer : A

Question. Refer to the given Venn diagram and select the option that correctly identifies P, Q and R.

Answer : C