CBSE Class 8 Science NSO Olympiad MCQs with Answers Set C

LOGICAL REASONING 

Question. How many such symbols are there in the given arrangement each of which is immediately preceded by a number and immediately followed by a letter?
5 8 # B F L ? 4 * M 7 9 G H 2 M 3 + 8 4 ? $ P Q 6 R 7 * H T
A. 2
B. 3
C. 4
D. 5
Answer : D

Question. Three different positions of a dice are shown here.
Which symbol will be on the face opposite to the face with symbol * ?

Answer : C

Question. Read the following information carefully.
(i) A # B means B is at 1 metre to the right of A.
(ii) A $ B means B is at 1 metre to the North of A.
(iii) A * B means B is at 1 metre to the left of A.
If M is facing towards North, according to
M # N $ O * P, in which direction is P with respect to M?
A. East
B. West
C. North
D. South
Answer : B

Question. Which of the following Venn diagrams best depicts the relationship amongst "Teachers, Men, Players"?

Answer : B

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

Answer : A

Question. Find the missing number, if a certain rule is followed row-wise or column-wise in the given matrix.

A. 4
B. 6
C. 9
D. 8
Answer : D

Question. Select the correct water image of the given Fig. (X).

Answer : B

Question. There is a certain relationship between figures (i) and (ii). Establish the similar relationship between figures (iii) and (iv) by selecting a suitable figure from the options which will replace the (?) in figure (iv).

Answer : A

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

Answer : C

Question. If P + Q means 'P is the brother of Q', P × Q means 'P is the wife of Q' and P ÷ Q means 'P is the daughter of Q', then which of the following means 'A is the niece of D'?
A. A ÷ B × C + D
B. A × B + C ÷ D
C. A + C ÷ B × D
D. A ÷ C + B ÷ D
Answer : C

SCIENCE

Question. The speed of sound in different media is different.
Which of the following options is correct regarding the speed of sound in different media?
A. Oxygen < Mud < Water
B. Ice < Stone < Alcohol
C. Fruit juice < Iron < Air
D. Steam < Kerosene < Mercury
Answer : C

Question. A cube of side a rests on the floor as shown in the given figure. Given that the pressure exerted by this cube on the floor is P, what is the pressure exerted by another cube of the same material of side 4a ?
(Take g = 10 N kg^–1)

A. P
B. 2P
C. 4P
D. 16P
Answer : D

Question. The given diagram shows a brick wall in between a man and a camp fire. How does thermal energy from the camp fire reach the man?

A. Radiation → Convection → Conduction
B. Conduction → Conduction → Convection
C. Radiation → Conduction → Convection
D. Radiation → Conduction → Radiation
Answer : B

Question. United Football Club is playing an evening match.
The team’s jersey has blue and white stripes. What colour would the stripes appear under floodlights which produce a yellow light?
A. Black and yellow
B. Blue and white
C. Blue and yellow
D. Black and white
Answer : C

Question. The given diagram shows the night sky in which stars are visible. Identify P, Q, R and S.

Answer : D

Question. The diagram shows a soft iron core coiled with wire.

When the switch is turned on, iron nails are attracted.
Which of the following ways will make the soft iron core to attract all the iron nails?
A. Decrease the number of cells
B. Increase the number of turns in coil
C. Place the soft iron core outside the coil
D. None of these
Answer : C

Question. A car is accelerating on a road in the direction shown in the figure. The tyre shown is connected to the engine. In which direction is the force of friction exerted by the road on the tyre?

A. P
B. Q
C. R
D. S
Answer : B

Question. Read the given statements and select the correct option.
Statement 1 : The size of a hydrogen balloon increases as it rises in air.
Statement 2 : The material from which the balloon is made can be easily stretched.
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 : D

Question. Anju walks 8 m to the east, then 6 m to the south, then 8 m to the west and finally 6 m to the north.
What is the distance covered and displacement of Anju?
Distance travelled        Displacement
A. 0 m                                      0 m
B. 0 m                                      28 m
C. 28 m                                    0 m
D. 28 m                                    28 m
Answer : C

Question. Deepak put twenty ice cubes of the same volume into four containers packed with different materials. He recorded the time taken for the ice to melt in each case. The table shows his results. Which of the boxes should he choose to carry ice that he needs to take to a friend’s house 120 km away?

Answer : D

Question. A positively charged object attracts a suspended light conducting ball. The light conducting ball can be
(i) negatively charged
(ii) positively charged
(iii) neutral
A. (i) only
B. (ii) only
C. (ii) and (iii) only
D. (i) and (iii) only
Answer : B

Question. The terminals of a battery are joined by a length of resistance wire. Which change, on its own will decrease the current through the battery?
A. Connecting an identical wire in series with the first one.
B. Covering the wire with plastic insulation.
C. Using a shorter wire of the same material and same thickness.
D. Using a thicker wire of the same material and same length.
Answer : B

Question. Metals are good conductors because
A. Outer electrons are strongly bound to the atom
B. Outer electrons are loosely bound to the atom
C. Inner electrons are loosely bound to the atom
D. Protons can detach from the nucleus and conduct electricity.
Answer : C

Question. Figure gives the speed-time graph of the motion of a car. What is the ratio of the distance travelled by the car during the last two seconds to the total distance travelled in seven seconds?

A. 1 : 9
B. 2 : 9
C. 1 : 3
D. 4 : 9
Answer : B

Question. Match the column I with column II and select the correct option from the given codes.
     Column I           Column II
(a) Jupiter            (i) Seven rings
(b) Saturn            (ii) Red planet
(c) Mars               (iii) Morning star
(d) Neptune         (iv) Great red spot
(e) Venus             (v) Fourteen moons
A. (a) – (iv), (b) – (i), (c) – (v), (d) – (iii), (e) – (ii)
B. (a) – (i), (b) – (ii), (c) – (iii), (d) – (iv), (e) – (v)
C. (a) – (v), (b) – (iv), (c) – (iii), (d) – (ii), (e) – (i)
D. (a) – (iv), (b) – (i), (c) – (ii), (d) – (v), (e) – (iii)
Answer : A

Question. Each beaker shown in the given options, contains two same sized strips of different metals fastened together and immersed in hydrochloric acid. After 5 minutes, which beaker will contain the least amount of zinc ions?

Answer : A

Question. Three unknown solutions are taken in test tubes.
Different indicators are added to these solutions to test their nature.

Answer : C

Question. Read the given statements about synthetic fibres and plastics carefully.
I. Polycot is a mixture of two types of fibres, polyester and cotton.
II. Calendar, woollen clothes and cold drink cans are all non-biodegradable.
III. Uniforms of firemen have coating of nylon to make them flame resistant.
IV. Polythene and PVC are the examples of thermosetting plastics.
Which of these statements is/are incorrect?
A. II and IV
B. I and III
C. Only II
D. II, III and IV
Answer : D

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

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

Question. Solution of which of the following oxides in water will change the colour of red litmus to blue?
A. Carbon dioxide
B. Copper oxide
C. Phosphorus trioxide
D. Sulphur dioxide
Answer : B

Question. Plants do not grow well when the soil is either too acidic or too basic. What should be added to the soil if it is too acidic?
A. Lemon juice
B. Vinegar
C. Quick lime
D. Organic matter
Answer : C

Question. Fill in the blanks by choosing an appropriate option.
I are used in the manufacture of detergents, fibres, polythene and other man-made plastics. II obtained from natural gas, is used in the production of fertilisers (urea). Petroleum is also called __II_I__ due to its great commercial importance.
                I                            II                            III
A. Fossil fuels             Petroleum gas           Black gold
B. Petrochemicals      Coal gas                    Diesel
C. Petrochemicals      Hydrogen gas           Black gold
D. Coal products        CNG                          Paraffin wax
Answer : A

Question. Mrs. Usha, a science teacher performed the following experiments :
Experiment 1 : She heated sugar in a China dish. A black substance was obtained along with caramel fumes.
Experiment 2 : She mixed sand and crushed naphthalene balls in a China dish. Then she covered the China dish with a watch glass with some ice kept on it and heated. Crystals of pure naphthalene were seen on the underside of the watch glass.
Identify the changes taking place in these experiments.
A. Experiment 1 - Chemical change, Crystallisation
Experiment 2 - Physical change, Decomposition
B. Experiment 1 - Physical change, Crystallisation
Experiment 2 - Chemical change, Sublimation
C. Experiment 1 - Physical change, Crystallisation
Experiment 2 - Physical change, Crystallisation
D. Experiment 1 - Chemical change, Decomposition
Experiment 2 - Physical change, Sublimation and Crystallisation
Answer : B

Question. Read the following statements and select the option which correctly fills any three blanks.
(i) In (a) irrigation emitters let out trickling water near the roots.
(ii) Removing the chaff from the grain is called
(b) , while separation of the grain from the crop is called (c) .
(iii) The organic substance obtained from dead plants and animal wastes is (d) .
(iv) Wheat and gram are rabi crops, while maize and (e) are kharif crops.
A. (b) – Winnowing, (d) – Manure, (e) – Oats
B. (b) – Winnowing, (c) – Threshing, (e) – Cotton
C. (a) – Drip, (d) – Fertilizer, (e) – Mustard
D. (a) – Sprinkler, (b) – Threshing, (c) – Winnowing
Answer : D

Question. Refer to the given diagram of nitrogen cycle

Match the letter from the above diagram with the processes/substances given below and select the correct option.
(a) Animal protein (b) Nitrate ion
(c) Plant protein (d) Nitrite ion
(e) Dead organic matter
     P         Q        R       S        T
A. (b)      (d)      (c)      (a)      (e)
B. (b)      (d)      (a)      (c)      (e)
C. (d)      (b)      (a)      (c)      (e)
D. (d)      (b)      (c)      (a)      (e)
Answer : C

Question. Red Data Book keeps the record of _______.
A. Endangered animals and plants
B. Endemic animals and plants
C. Extinct animals and plants
D. Both A and C
Answer : B

Question. Study the given flow chart.

Which of the following is suitable heading for

Answer : D

Question. Natasha put a plant cell and an animal cell of similar size in two similar dishes containing the same amount of water overnight. The next day, she observed the cells under the microscope and noticed that the animal cell has burst and the plant cell looked more bloated.
She drew the following conclusions:
(i) The animal cell has only a thin layer of cell membrane. When too much water enters it, it bursts.
(ii) Plant cell has cell wall made up of cellulose which is very strong material and prevents the cell from bursting.
(iii) The plant cell contains vacuole and therefore can absorb more water.
(iv) The animal cell does not possess vacuole.
Which of the above given conclusions are correct?
A. (i) and (ii)
B. (iii) and (iv)
C. (i), (ii) and (iii)
D. All of these
Answer : B

Question. Select the incorrect statement regarding the given figure.

A. The part labelled P produces both male gametes and androgen.
B. The sperms collect and mature in Q.
C. The parts R and S have no role in reproduction.
D. The part T is located outside the abdominal cavity and protects P and Q inside it.
Answer : B

Question. Study the given Venn diagram. X is likely to be _______.

A. A group of people smoking cigarettes
B. Youngsters dancing in a disco
C. A farmer spraying pesticides near a river
D. Construction work going on at a building site
Answer : A

Question. Which of the following organisms has been incorrectly described?

Answer : A

Question. Study the given flow chart.

What are P, Q and R respectively?

Answer : D

Question. Transpiration is the loss of water from the surface of a plant. Which of the following statements describes why this process is useful for plants?
A. It cools down plants, preventing overheating on sunny days.
B. It helps the plant to get rid of excess water, protecting plant cells from bursting.
C. It enables the mass flow of inorganic nutrients and water up the plant body.
D. Both A and C
Answer : C

Question. Unscramble the given words and select the option that gives name of the process of washing wool with soap water to remove dirt and greese.
A. NSERHAIG
B. DCNRIAG
C. GTRNSOI
D. GURSOCNI
Answer : B

Question. Refer to the given figure showing cross-section of a flower and select the correct option to fill the blanks in the following paragraph.

Fertilization takes place when pollen grains from the male part, (i) reach the part of the flower labelled (ii) . The (iii) increases in size and becomes the fruit, while (iv) becomes the seeds.
     (i)   (ii)    (iii)    (iv)
A. P      R      Q      R
B. T      Q      Q      R
C. S      Q      R      Q
D. S      R      Q      R
Answer : C

ACHIEVERS SECTION

Direction : Refer to the given passage and answer questions a  and b.

We can see an image not only on a plane surface, but also on a curved one. For example we can see our image on asteel spoon. The image formed at the outer surface of a spoon is upright and the image formed at the inner surface of the spoon is smaller and inverted.

Question a. The outer surface of the spoon which is bulging out acts like a ________ and inner side of spoon acts like a ________.
A. Concave mirror, convex mirror
B. Convex mirror, concave mirror
C. Plane mirror, convex lens
D. Concave lens, concave mirror
Answer : B

Question b. If we move the spoon (inner surface) slowly away from our face, how does the image change?
A. The image becomes bigger and it appears upright.
B. The image becomes bigger and it appears inverted.
C. The image becomes smaller and it appears inverted.
D. The image becomes smaller and it appears upright.
Answer : C

Question. Refer to the given figures of bacteria X, Y and Z and read the statements (i), (ii), (iii) and (iv) regarding them.

(i) Bacterium X can be causal organism of typhoid.
(ii) Bacterium Y can cause a disease which disrupts proper exchange of gases.
(iii) Bacterium Z can convert lactose sugar of milk into lactic acid.
(iv) Bacterium X can be the causal organism of cholera.
Which of these statements are incorrect?
A. (i) only
B. (i) and (ii) only
C. (ii), (iii) and (iv) only
D. (i), (ii), (iii) and (iv)
Answer : B

Question. A copper vessel exposed to moist air for a long time is shown in figure I and sulphur powder is burnt in oxygen as shown in figure II.

1, 2, 3 and 4 are respectively
A. CuO, CO₂, SO₂, H₂SO₃
B. CuCO₃, Cu(OH)₂, H₂SO₃, SO₂
C. Cu, CuO, H₂S, H₂SO₄
D. Cu(OH)₂, CuCO₃, SO₂, H₂SO₃
Answer : D

Question. Diabetics who are on rapid-acting insulin are advised not to wait more than 15 minutes to eat after taking an insulin shot. Which of the following best explains this?
A. Insulin is required for the proper absorption of nutrients in the small intestine.
B. The insulin injection may prevent the body from absorbing the glucose necessary to maintain blood glucose concentrations.
C. The injection of insulin can lead to dangerously low blood glucose concentration.
D. The insulin injection can lead to dangerously low blood calcium concentration
Answer : B