CBSE Class 8 Science NSO Olympiad MCQs with Answers Set Q

MENTAL ABILITY

Question. Which natural number is nearest to 9217, which is completely divisible by 88?
(A) 9152
(B) 9240
(C) 9064
(D) 9184
Answer : B

Question. The value of 1/1. 2. 3 + 1/2. 3. 4 + 1/3. 4. 5 + 1/4. 5. 6 is equal to _______.
(A) 7/30
(B) 11/30
(C) 13/30
(D) 17/30
Answer : A

Question. The value of

(A) 0.024
(B) 0.24
(C) 2.4
(D) 24
Answer : A

Question. If in a certain language, FLOWER is coded as UOLDVI, then how is TERMINAL coded in that language ?
(A) FLKPMROZ
(B) GVINRMZO
(C) RVNIGLKA
(D) MNIVGYEO
Answer : B

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

Answer : B

Question. Present ages of X and Y are in the ratio 5 : 6 respectively. Seven years hence this ratio will become 6 : 7 respectively. What is X's present age ?
(A) 35 years
(B) 42 years
(C) 49 years
(D) Can't be determined
Answer : A

Question. The value of 2ⁿ⁺⁴ - 2 x 2ⁿ/2x4⁽ⁿ⁺³⁾ + 2^-3 is equal to _____.
(A) 2ⁿ⁺¹
(B) (9/8 - 2ⁿ)
(C) (-2ⁿ⁺¹ + 1/8)
(D) 1
Answer : D

Question. If ‘+’ stands for 'division, ‘÷’ stands for ‘multiplication’, ‘×’ stands for ‘subtraction and’ ‘–’ stands for ‘addition’, then which one the following equations is correct ?
(A) 18 ÷ 6 × 7 + 5 – 2 = 22
(B) 18 × 6 + 7 ÷ 5 – 2 = 16
(C) 18 ÷ 6 – 7 + 5 × 2 = 20
(D) 18 + 6 ÷ 7 × 5 – 2 = 18
Answer : D

Question. Choose the correct mirror-image of figure (X) if the mirror is placed along MN.

Answer : C

Question. By selling a pen for ₹ 15, a man loses one-sixteenth of what it costs him. The cost price of the pen is _____.
(A) ₹ 16
(B) ₹ 18
(C) ₹ 20
(D) ₹ 21
Answer : A

Question. The simple interest on a certain sum of money for 3 years at 8% per annum is half the compound interest on ₹ 4000 for 2 years at 10% per annum. The sum placed on simple interest is _____.
(A) ₹ 1550
(B) ₹ 1650
(C) ₹ 1750
(D) ₹ 2000
Answer : C

Question. The cost of cultivating a square field at the rate of ₹ 135 per hectare is ₹ 1215. The cost of putting a fence around it at the rate of 75 paise per metre would be _____.
(A) ₹ 360
(B) ₹ 810
(C) ₹ 900
(D) ₹ 1800
Answer : C

Question. One card is drawn at random from a pack of 52 cards. What is the probability that the card drawn is a face card ?
(A) 3/13
(B) 4/13
(C) 1/4
(D) 9/52
Answer : A

Question. Study the bar graph carefully.

In which year was the percentage increase in production maximum as compared to the previous year?
(A) 2002
(B) 2001
(C) 1999
(D) 1996
Answer : D

Question. Choose the odd numeral group.
(A) 1,4,3,8
(B) 2,3,3,8
(C) 3,2,3,8
(D) 5,3,2,9
Answer : D

SCIENCE

Question. When a light ray is reflected repeatedly by a set of parallel plane mirrors, the intensity of light rays decreases after some reflections. This is because of ____.
(A) Poor reflection from mirrors
(B) Absorption of some amount of light by mirrors
(C) Dispersion of light when the rays travel through the atmosphere
(D) Scattering of light by the mirrors
Answer : B

Question. Sanchi conducted an experiment to understand how the position of the object can affect the shadow formed on the screen. When she placed the object at position Y shadow 1 was formed on the screen as shown.

When the object was placed at position X, which of the following would be observed about the shadow on the screen?
1. The shadow would be upright. 2. The shadow would be inverted.
3. The shadow would be bigger than shadow 1. 4. The shadow would be smaller than shadow 1.
(A) 1 and 3 only
(B) 2 and 3 only
(C) 1 and 4 only
(D) 3 and 4 only
Answer : C

Question. Which of the following statements about weight is/are false?
1. Weight does not change when location changes.
2. Weight is a force.
3. Weight is measured in kilograms.
4. Weight is proportional to the amount of gravity acting on an object.
(A) 1 only
(B) 1 and 3 only
(C) 2 and 4 only
(D) 1, 3 and 4 only.
Answer : B

Question. Study the given circuit diagram.

How many bulbs will light up when switches A and B are closed in different situations?
Only switch A is closed        Only switch B is closed
(A) 4                                                    2
(B) 4                                                    3
(C) 0                                                    2
(D) 0                                                    3
Answer : D

DIRECTION (Q.Nos. a & b) : Two tuning forks A and B vibrate with frequencies in the ratio 3 : 8 and their wavelengths in the ratio 4 : 5.

Question a. The tuning fork A produces relatively _____.
(A) Shriller sound than tuning fork B.
(B) Flatter sound than tuning fork B.
(C) Louder sound than tuning fork B.
(D) Wave of more wavelength than that of tuning fork B.
Answer : B

Question b. The wave producing lower wavelength is _____.
(A) Tuning fork A
(B) Tuning fork B
(C) Both A and B
(D) Cannot be determined
Answer : A

Question. Which of the following graphs correctly shows the changes in the length of a shadow cast by an object during the day?

Answer : A

Question. When some liquid evaporates, the average speed of the molecules remaining will ____.
(A) Increase because the more energetic molecules have left
(B) Decrease because the more energetic molecules have left
(C) Remain unchanged because all molecules have about the same speed
(D) Increase because there are fewer molecules
Answer : B

Question. One cannot see through fog because _____.
(A) Fog absorbs light
(B) Refractive index of fog is unity
(C) Light suffers total internal reflection at the droplets in fog
(D) Light is scattered by the droplets in fog
Answer : D

Question. At a particular time of the day, the ratio of length of a tree and the length of its shadow is found to be 2.5. Now the length of the shadow of a pole is 8 m. The length of the pole is ____.
(A) 15 m
(B) 20 m
(C) 25 m
(D) 30 m
Answer : B

Question. From the displacement-time graph shown here, find the velocity of the body as it moves from C to D.

(A) 2 m s^–1
(B) 3 m s^–1
(C) 4 m s^–1
(D) 5 m s^–1
Answer : C

Question. Read the statements carefully and mark the correct option.
Statement 1 : There will be no action of external force on an object moving with uniform velocity.
Statement 2 : The force acting on an object need not cause motion. It may deform the dimensions of 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 and statement 2 is false.
(D) Both statements 1 and 2 are false.
Answer : B

Question. The electrical circuit shown below contains four light bulbs, four switches and four dry cells.

What is the minimum number of switches that has to be closed in order for all the light bulbs to be lit?
(A) 1
(B) 2
(C) 3
(D) 4
Answer : C

Question. Birds do not feel electric shock while sitting on current carrying uninsulated wires because ___.
(A) The feathers of birds act as insulator and hence the current does not pass through them
(B) The resistance offered by the body of birds is very high
(C) The current does not pass through the body as the claws of birds are non-conducting
(D) The potential difference between the two claws of the birds is very small
Answer : D

Question. Frictional force exists in which of the following cases ?
(A) Exists only for moving bodies.
(B) Exists only for bodies which are at rest.
(C) Exists for both moving and non-moving bodies.
(D) None of these.
Answer : C

Question. Plastic is not environment friendly because it takes several years to decompose and burning of plastic also causes formation of poisonous gas. So a responsible citizen should remember 4R principle. Here 4R stands for
(A) Renovate, Reuse, Recurrent and Recover
(B) Report, Recall, Reduce and Recycle
(C) Reduce, Reuse, Recycle and Recover
(D) Reduce, Reuse, Refuse and Reform
Answer : C

Question. Which one of the following was used for street lighting for the first time in London in 1810 and in New York around 1820?
(A) Natural gas
(B) Coal gas
(C) Petroleum gas
(D) Kerosene
Answer : B

Question. X is a metal which can replace Y and Z both from their salt solutions. Y can replace Z but not W.
W can replace both Y and Z but not X. What is the correct reactivity order of X, Y, Z and W?
(A) W > X > Y > Z
(B) X > Y > Z > W
(C) X > W > Y > Z
(D) X > W > Z > Y
Answer : C

Direction (Q.Nos. a & b) : Lalita has taken sulphur powder (P) in a deflagrating spoon and burnt it and put it in a gas jar. Then she removed the spoon and added water. In another experiment she has taken water in one beaker and added a small piece of sodium (Q). After sometime she took both the solutions and checked them with litmus paper.

Question a. What result would she expect ?
(A) In case P : blue to red, in case Q : red to blue
(B) In both cases P and Q : blue to red
(C) In case P : red to blue, in case Q : blue to red
(D) In both cases P and Q : red to blue
Answer : A

Question b. The reaction occurring in case of (P) is
(A) SO₂ + H₂O → H₂SO₄
(B) SO₃ + 2H₂O → H₂SO₄ + H₂O
(C) SO₂ + H₂O → H₂SO₃
(D) 2SO³ + 2H₂O → 2H₂SO₄ + O₂
Answer : C

Question. Some substances catch fire very easily like alcohol, petrol, LPG, etc. These are called inflammable substances but some do not catch fire easily like water. What could be the reason for it?
(A) Boiling point of inflammable substances is higher.
(B) Latent heat of vaporisation is lower for inflammable substances.
(C) Ignition temperature of inflammable substance is lower.
(D) Both (B) and (C).
Answer : C

Question. Match the following and select the correct option.
              Column I                                   Column II
(P) Human body metabolism             (i) Rapid combustion
(Q) Fire crackers                               (ii) Spontaneous combustion
(R) Burning of domestic gas             (iii) Slow combustion
(S) Yellow phosphorus                      (iv) Explosion
(A) (P) - (iii), (Q) - (iv), (R) - (ii), (S) - (i)
(B) (P) - (iii), (Q) - (iv), (R) - (i), (S) - (ii)
(C) (P) - (ii), (Q) - (iv), (R) - (iii), (S) - (i)
(D) (P) - (ii), (Q) - (iv), (R) - (i), (S) - (iii)
Answer : B

Question. Which one of the following is prepared using only one type of material?
(A) Polycot
(B) Polywool
(C) Terrycot
(D) Polyester
Answer : D

Question. What will happen to the given cell if the labelled cell organelle is removed from it ?

(A) Cell will undergo autodigestion.
(B) Protein synthesis will stop.
(C) Cell will not undergo division.
(D) Cell will loose rigidity and internal structures will get unprotected.
Answer : D

Question. _P_ are single-celled organisms with varying shapes such as round, rod or spiral. _Q__ are autotrophic organisms having undifferentiated plant bodies. __ R_ are plant-like organisms exhibiting heterotrophic mode of nutrition. __S_ are organisms which exhibit characteristics of both living as well as nonliving things.
Select the correct sequence of terms to complete the above paragraph

Answer : D

Question. Which of the following animals are correctly categorised ?
      Oviparous                     Viviparous
(A) Human, Cow                 Snake, Pigeon
(B) Hen, Snake                   Human, Crocodile
(C) Pigeon, Crocodile         Rat, Horse
(D) Toad, Earthworm           Cockroach, Cat
Answer : C

Question. Match column I with column II and select the correct option from the codes given below.
      Column I                Column II
(a) Pathogen                (i) The carriers of diseases
(b) Vaccination             (ii) Arrests growth of microorganisms
(c) Pasteurization        (iii) Microbes that cause diseases
(d) Vector                    (iv) Gives immunity
(A) (a) - (ii), (b) - (i), (c) - (iii), (d) - (iv)
(B) (a) - (iii), (b) - (iv), (c) - (ii), (d) - (i)
(C) (a) - (i), (b) - (ii), (c) - (iii), (d) - (iv)
(D) (a) - (iv), (b) - (iii), (c) - (ii), (d) - (i)
Answer : B

Question. Cause Effect Global warming Ice at North and South poles may melt causing sea-level to rise & floods to occur.
Which of the following can prevent the effect from happening ?
(A) Deforestation
(B) Use of unleaded petrol
(C) Use of leaded petrol
(D) Both (A) & (B)
Answer : B

Question. The given figure shows more than one sperm near an egg during a stage of reproduction in animals.
Which of the following statements are correct regarding this ?
(i) Female animals produce sperms.
(ii) Only one egg usually gets fertilized by many sperms.
(iii) After fertilization, egg contains the genetic materials of both parents.
(iv) Fusion of sperm and egg does not necessarily take place inside the female body.

(A) (i) & (ii)
(B) (ii) & (iv)
(C) (iii) & (iv)
(D) (i), (ii) & (iv)
Answer : C

Question. What is the correct order of agricultural practices in crop production ?
(A) Sowing → Tilling → Irrigation → Manuring → Weeding → Harvesting → Winnowing → Threshing → Storage
(B) Tilling → Sowing → Manuring → Irrigation → Weeding → Harvesting → Threshing → Winnowing → Storage
(C) Sowing → Manuring → Tilling → Irrigation → Weeding → Harvesting → Threshing → Winnowing → Storage
(D) Irrigation → Tilling → Sowing → Weeding → Manuring → Harvesting → Winnowing → Threshing → Storage
Answer : B

Question. In a classroom discussion, three students made the following statements.
Shikha : Fertilizers are chemical substances which are rich in a particular nutrient.
Ritesh : Fertilizers increase the water holding capacity of the soil.
Abhishek : Fertilizers used in excess provide lots of humus to the soil.
Which student(s) made incorrect statement(s) ?
(A) Shikha & Ritesh
(B) Ritesh & Abhishek
(C) Abhishek & Shikha
(D) Shikha only
Answer : B

Question. Which of these is an endemic species of India ?

Answer : C

Question. Read the following statements.
(i) Hormone A helps a mother to feed her baby as it induces production of milk.
(ii) Hormone B helps to regulate amount of glucose in blood so that body can get energy.
Refer the given figure and select the correct statement regarding the above given hormones.

(A) Gland Z secretes hormone B.
(B) Hormone B can either be insulin or glucagon and is secreted by gland Y.
(C) A is growth hormone (GH) and is secreted by gland X.
(D) Gland Y secretes both the hormones A and B.
Answer : B

Question. On the basis of the given graph select the correct statement.

(A) X shows the amount of pollutants present in water.
(B) Y shows the population of fishes and other fresh water organisms.
(C) Y shows the amount of oxygen dissolved in water.
(D) Y shows the population of bacteria and algae.
Answer : D

Question. The given graph shows various air pollutants and their effects labelled X, Y and Z . Identify X, Y and Z and select the correct option.

Answer : C