CBSE Class 8 Science NSO Olympiad MCQs with Answers Set G

LOGICAL REASONING

Question. Select a figure from the options which will complete the given figure matrix.

Answer : A

Question. Study the given information carefully and answer the question that follows.
• P, Q, R, S, T, U and V are sitting in a row facing North.
• T is to the immediate right of V.
• P is the neighbour of R and U.
• V is 4th to the right of Q.
• Person who is third to the left of U is at one of the ends. 
Who is second to the right of U?
A. T
B. V
C. S
D. P
Answer : A

Question. Which of the following options does not satisfy the same condition of placement of dots as in Fig. (X)?

Answer : B

Question. In a certain code language, if 'TUTORIAL' is written as 'WRWLUFDI', then how will 'GUIDANCE' be written in that language?
A. HFQDGLXJ
B. FGPLKYJZ
C. JRLADFKB
D. JRLADKFB
Answer : D

Question. Find the missing number, if same rule is followed in all the three figures.

A. 12
B. 16
C. 14
D. 9
Answer : A

Question. The given question consists of a set of four figures P, Q, R and S showing a sequence of folding of a piece of paper. Fig. (S) shows the manner in which the folded paper has been cut. Select the figure from the options which would most closely resemble the unfolded form of Fig. (S).

Answer : A

Question. In which of the following figures, Fig. (X) is exactly embedded as one of its parts?

Answer : B

Question. How many pair of letters are there in the word OPERATION which have as many letters between them in the word as in the English alphabet?
A. Five
B. Six
C. Seven
D. More than seven
Answer : D

Question. Which of the following options will continue the same series as established by the Problem Figures?

Answer : C

Question. Priyanshu walked 8 m in East, then he turned right and walked 3 m. Again he turned to the right and walked 12 m. How far is he now from the starting point?
A. 20 m
B. 4 m
C. 5 m
D. 23 m
Answer : C

SCIENCE

Question. A 20 Pa pressure is applied on the head of a nail placed perpendicular to the surface of a wall. If the area of cross-section of the tip of the nail is (1/10) times the area of cross-section of the head, the pressure exerted at the wall is
A. 10 Pa
B. 20 Pa
C. 200 Pa
D. None of these
Answer : C

Question. Two metal spheres are mounted on insulating stands. Sphere P is initially uncharged and sphere Q is initially positively charged. A metal rod, held by an insulating handle, is placed in contact with P and Q as shown.

What are the charges on P and Q after the rod is placed in contact with them?
Charge on P              Charge on Q
A. Positive                  Positive
B. Positive                  Uncharged
C. Uncharged             Positive
D. Uncharged             Uncharged
Answer : A

Question. A fire can be made by rubbing two objects together such as rubbing two pieces of rock having rough surfaces.
Which of the following statements explain why a fire can be made by rubbing two objects together?
(i) Friction slows down moving objects.
(ii) Fire gives out heat and light energy.
(iii) Friction produces heat.
(iv) Fire has no mass.
A. (ii) only
B. (iii) only
C. (i), (ii) and (iii) only
D. (ii) and (iv) only
Answer : B

Question. Two forces of equal magnitude F act on two isolated bodies P and Q as shown in the figure. The mass of body Q is three times that of body P. The magnitude of the acceleration of P is

A. Three times that of Q
B. (1/3) that of Q
C. Nine times that of Q
D. (1/9) that of Q.
Answer : A

Question. The speed of sound in air, water and steel is different.
If the speed of sound in air, water and steel is represented by Va, Vw and Vs respectively, then which of the following sequences is correct about the speed of sound in ascending order?
A. Va, Vw, Vs
B. Vs, Vw, Va
C. Vw, Vs, Va
D. Va, Vs, Vw
Answer : A

Question. In the given figure, two mirrors X and Y are situated at an angle of 60° with each other and a ray of light is incident on mirror X at an angle of 50°. When the ray is reflected by the mirror Y, then what is angle of reflection at this mirror?

A. 35°
B. 55°
C. 50°
D. 20°
Answer : D

Question. The diagram shows identical lamps X and Y connected in series with a battery. The lamps light with normal brightness. If a third identical lamp Z is connected in parallel with lamp X, then what will happen to the brightness of lamp Y?

A. Brighter than normal
B. Normal
C. Dimmer than normal
D. Very dim (cannot be seen)
Answer : A

Question. The device used to prevent the flow of excess current in the circuit is
A. Switch
B. Fuse
C. Bulb
D. Coil
Answer : B

Question. Read the given statements and select the correct option.
Statement 1 : The seasons are caused by the tilt of Earth's axis.
Statement 2 : The axis of Earth is tilted at an angle of 23(1/2)° to the plane of its orbit.
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. Three containers P, Q and R made of metal are filled with chilled water, ice cubes and boiling water with vapour respectively. These containers are kept at room temperature. Which of the following graph shows the temperature variations in all the containers correctly?

Answer : D

Question. The displacement-time graph of a lift climbing from the ground floor to the top of the building is given here. Which of the following statements are true about the graph?

(i) At point A, the lift is stationary.
(ii) Velocity of lift is decreasing from point B to C.
(iii) At point C, the lift is at zero velocity.
(iv) Velocity of lift is minimum at B.
A. (i) and (iii) only
B. (ii) and (iv) only
C. (i), (ii) and (iii) only
D. (ii), (iii) and (iv) only
Answer : C

Question. A cylinder is placed on a balance as shown in the figure. Water is poured into the cylinder and the reading of the balance is recorded for different heights of water in the
cylinder.

Which graph correctly shows the variation of the balance reading (say m) with the height (say h)?

Answer : C

Question. Fill in the blanks by choosing an appropriate option.
The loudness of sound depends on its (i) .
The (ii) determines the pitch of a sound.
A bird makes a (iii) sound where as a lion makes
a (iv) sound. Usually voice of a woman has
a (v) frequency than that of a man.

Answer : C

Question. Read the given statements and select the correct option.
Statement 1 : It takes a much longer time and covers more distance to stop a moving ship in water than a moving car with same speed on the road.
Statement 2 : The friction on water surface is much less than the solid 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 but statement 2 is false.
D. Statement 1 is false but statement 2 is true.
Answer : A

Question. A person standing at the centre of a rectangular room is looking into a 1 m long mirror at the opposite end of the room. How much of the painted wall can he see through the 1 m long mirror?

A. 1 m
B. 2 m
C. 3 m
D. 4 m
Answer : C

Question. Which of the following statements is/are correct?
I. The flame of a Bunsen burner is blue when the air hole is open and yellow when the air hole is closed.
II. The liquid or solid wax never catches fire.
III. A substance cannot catch fire if its temperature is higher than its ignition temperature.
IV. Water should be poured over burning petrol, kerosene or diesel.
V. The middle zone of a candle emits the least light.
A. I and II only
B. III and IV only
C. II, III and IV only
D. V only
Answer : A

Question. Rupali, a class 8 student classified a few changes occurring around us as shown in the table

Which of her observations are incorrect?
A. I and II only
B. II and III only
C. I, IV and V only
D. II, III, IV and V only
Answer : C

Question. Ms Shelja, a science teacher conducted an activity as shown in the given figure :
She collected the ash and made its solution with water.
Which of the following statements is/are correct?

I. The formula of the ash is MgO.
II. The solution formed will turn methyl orange pink and phenolphthalein colourless.
III. The solution will have no effect on blue litmus paper.
A. I only
B. I and III only
C. II only
D. I, II and III
Answer : B

Question. Suhani, a class 8 student has listed the important properties and uses of a few plastics in the given table.

W, X, Y and Z could be respectively
A. Polystyrene, polythene, melamine and teflon
B. PVC, polythene, bakelite and melamine
C. Polythene, PVC, bakelite and melamine
D. Polythene, melamine, bakelite and teflon.
Answer : C

Question. Match column I with column II and select the correct option from the given codes.

A. P – (iv), Q – (i), R – (ii), S – (v)
B. P – (ii), Q – (iii), R – (i), S – (iv)
C. P – (iv), Q – (i), R – (ii), S – (iii)
D. P – (iii), Q – (iv), R – (v), S – (i)
Answer : C

Question. Read the given passage and fill in the blanks by choosing an appropriate option.
The process of conversion of wood into coal is called (i) . There are three main varieties of coal which vary in their carbon content. (ii) has upto 96 % of carbon, (iii) has about 65 % of carbon while (iv) has about 38 % of carbon.

Answer : C

Question. Match column I with column II and select the correct option from the given codes.
              Column I                                   Column II
P. Spontaneous combustion              (i) Sulphur dioxide
Q. Supporter of combustion              (ii) Carbon dioxide
R. Fire extinguisher                           (iii) Oxygen
S. Incomplete combustion                 (iv) Sodium bicarbonate + conc. sulphuric acid
                                                          (v) Carbon monoxide
T. Combustion of coal and diesel      (vi) Phosphorus

Answer : D

Question. Ronit, a class 8 student took 20 mL of dilute HCl in four different flasks. He added 10 mL of pure water to flask I, 20 mL of pure water to flask II, 20 mL of concentrated HCl to flask III and 30 mL of the same solution of dilute HCl to flask IV.
pH of the solution will not change in
A. Flask I
B. Flask II
C. Flask III
D. Flask IV.
Answer : D

Question. Following is the data of four species (S₁ – S₄) present (+) or absent (–) in five different habitats (P, Q, R, S and T).
Which species has the maximum diversity?

Answer : B

Question. Refer to the given flow chart and select the incorrect statement

A. In P, bulb like projection called bud may occur on the body of the parent plant.
B. Q can help in maintaining pure lines for hybridisation experiments.
C. Pollination in R is non-directional while in S and T it is highly specific and directional.
D. In T, pollen grains are produced in large numbers while in Q they are fewer.
Answer : C

Question. Refer to the given food web in an aquatic ecosystem.

In which of the following species would a toxic pollutant present in water body probably reach the highest concentration. [The arrows represent energy flow and the letters represent different species.]
A. S
B. Q
C. R
D. T
Answer : D

Question. Refer to the given Venn diagram and select the incorrect statement regarding animals X, Y and Z.

A. Both X and Z can regulate their body temperatures but X is oviparous and Z is viviparous.
B. Y may have an exoskeleton of scales and its body is divisible into head, trunk and tail.
C. X could be stork, Y could be arowana and Z could be dolphin.
D. X has hollow bones and Y respires through moist skin and buccopharyngeal cavity
Answer : D

Question. Refer to the given dichotomous key and select the correct statement.
(i) (a) Single parent is involved in reproduction.-Go to (ii)
(b) Two parents are involved in reproduction.-Go to (iii)
(ii) (a) The nucleus of the parent body divides only once. - P
(b) The nucleus of the parent body divides repeatedly. - Q
(iii) (a) Fertilisation occurs outside parent body. - R
(b) Fertilisation occurs inside parent body. - Go to (iv)
(iv) (a) Embryonic development occurs outside parent body. - S
(b) Embryonic development occurs inside parent body. - T
A. P occurs in Plasmodium while Q occurs in Amoeba.
B. In S, both the types of gametes are released from the body while in T, only one type of gamete is released from the body.
C. R involves only mitosis while S involves both mitosis and meiosis.
D. In S, eggs are surrounded by protective calcareous shell while in T protective calcareous shell is absent around the eggs.
Answer : D

Question. Read the following statements and select the correct option.
Statement 1: Pheromones are used as biological method to control pest.
Statement 2: Pheromones lure adult male insects into special traps and prevent them from breeding.
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. Refer to the given flow chart and select the incorrect statement regarding P, Q, R and S.

A. P could be particles of carbon which enter human lungs.
B. Excessive Q in atmosphere traps large amount of Sun's heat and increases the Earth's temperature.
C. S reacts with water present in the atmosphere to form sulphuric acid.
D. Catalytic converter converts Q and S into gas R.
Answer : D

Question. Study the given diagram of human heart and select the correct statement regarding its parts labelled X, Y and Z.

A. All systemic arteries arise from Y.
B. Z transports oxygenated blood from lungs to the left atrium.
C. Y carries oxygenated blood from lungs to right atrium.
D. X carries deoxygenated blood from left atrium to lungs.
Answer : B

Question. Study the given experimental set up and select the correct option regarding it.

A. Both glucose and starch are able to diffuse through the Visking tubings into the boiling tubes.
B. Exosmosis of water from Visking tubing Q will take place only after conversion of starch into glucose by digestive enzyme.
C. Initially only the contents of Visking tubing Q will give positive iodine test but after 30 minutes the contents of both Visking tubings will give positive iodine test.
D. None of these
Answer : D

Question. What is the major difference between a human skin cell and a human egg cell?
A. The egg cell has twice as many chromosomes as the skin cell.
B. The egg cell has half as many chromosomes as the skin cell.
C. The skin cell has no genetic information in its chromosomes.
D. Only the egg cell has a nucleus.
Answer : B

Question. Refer to the given table. Identify X, Y and Z and select the correct statement.

A. X is more suitable for summer clothing while Y is more suitable for winter clothing.
B. X is jute, Y is silk and Z is linen.
C. X on burning gives odour of burning hair whereas Y on burning gives odour of charred meat.
D. Both A and B
Answer : A

Question. Refer to the given figures P, Q, R and S and select the correct statement regarding them.

A. Q and R show holozoic heterotrophic nutrition whereas P shows mixotrophic nutrition.
B. S is helpful in crop growth and increases capacity of soil to hold water.
C. P and S use pseudopodia for feeding and locomotion.
D. In Q, cilia help in locomotion and catching prey while in R flagella help in locomotion.
Answer : D

ACHIEVERS SECTION

Direction (Q. No. a and b): Read the given passage
and select the correct option for the following questions.
The sound returning back towards the source after suffering reflection from a distant obstacle like wall, hill etc. is called an echo. A cracker is fired by a child. The child hears an echo from a cliff 4 seconds after the sound produced by a cracker. The speed of sound in air at 20°C is 344 m s^–1.

Question a. What is the minimum distance between the observer and the obstacle for echo to be heard?
A. 17.2 m
B. 15.2 m
C. 14.2 m
D. 34.4 m
Answer : A

Question b. How far is the cliff from the child?
A. 344 m
B. 688 m
C. 200 m
D. 300 m
Answer : B

Question. Refer to the given graph representing two crop fields X and Y that have been treated by different types of materials for nutrient replenishment, keeping other environmental factors same.

Select the incorrect statements regarding these crop fields X and Y.
A. Materials used for treating crop field X could be organic substances while those used for Y could be inorganic substances.
B. Materials used for crop field X are nutrient specific while those used for crop field Y are not nutrient specific.
C. Gradual decline in yield of crop field Y is due to killing of useful soil microbes.
D. Persistent yield of crop field X is due to replenishment of nutrients by gradual decomposition of organic matter.
Answer : B

Question. Refer to the given paragraph where few words have been italicised.
Hormones are produced by organs called endocrine glands. These are ductless glands. Very small quantity of different hormones is required by our body. Adrenaline is secreted when we are stressed or excited. Liver regulates the sugar metabolism in the body by its hormone insulin. Pineal glands secrete calcitonin while thyroid glands secrete melatonin.
Select the correct option regarding these.
A. Insulin should be replaced by aldosterone.
B. Liver should not be replaced as it is correctly mentioned.
C. Positions of pineal and thyroid should be interchanged.
D. Adrenaline should be replaced by progesterone.
Answer : C

Question. Ms Deepika conducted a few experiments to explain the properties of metals and non-metals. She set up the experiments as shown in the given figure.

She noted her observations as :
I. No reaction will take place in beakers (iv) and (v).
II. H2 gas will be evolved in beakers (i), (ii) and (iii).
III. A vigorous reaction will take place in beaker (i) while no reaction will occur in beaker (ii).
IV. Two different gases will be evolved in beaker (iv).
The correct observations are
A. II, III, and IV only
B. II and IV only
C. I and III only
D. II and III only.
Answer : C