CBSE Class 8 Science NSO Olympiad MCQs with Answers Set I

LOGICAL REASONING

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

Answer : A

Question. If in a certain code language, ACNE is coded as 3 5 16 7, then how will PAIR be coded in the same language?
A. 18 3 11 20
B. 18 3 11 25
C. 13 4 11 18
D. 15 4 19 27
Answer : A

Question. Count the number of triangles in the given figure.

A. 43
B. 46
C. 42
D. None of these
Answer : D

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

A. 35
B. 25
C. 28
D. 30
Answer : A

Question. Select the correct water image of the given figure.

Answer : A

Question. Which of the following interchanges in signs makes the given statement true?
5 × 15 ÷ 7 – 20 + 4 = 77
A. – and + B. + and ×
C. ÷ and +
D. ÷ and ×
Answer : C

Question. How many 8’s are there in the given series, which are immediately preceded by a number which does not divide it but followed by a number which divides it?
4 8 2 8 2 8 3 8 5 8 8 5 3 2 8 2 3 8 4 7 1 5 8 3 8 2 8 6 8 8 6
A. 1
B. 2
C. 3
D. 4
Answer : D

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

Answer : D

Question. In the question below, two statements followed by two conclusions numbered I and II are given. You have to take the two given statements to be true even if they seem to be at variance of commonly known facts and decide which of the conclusion(s) logically follow(s) from the two given statements, disregarding commonly known facts.
Statements : Some books are papers. Some papers are notebooks.
Conclusions : I. Some papers are books.
II. Some notebooks are papers.
A. Only conclusion I follows
B. Only conclusion II follows
C. Neither I nor II follows
D. Both I and II follow
Answer : D

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

Answer : C

SCIENCE

Question. Which of the following statements is/are always true regarding a converging lens?
I. When the object is placed nearer to the focal point, the image gets bigger.
II. When the object is placed away from the lens, image gets smaller.
III. When the object is placed very far away from the lens, the image distance approaches focal length.
A. I and II only
B. II and III only
C. I and III only
D. II only
Answer : C

Question. Which sound wave shown here is high-pitched but soft?

Answer : C

Question. The diagram shows the water levels in a water manometer which is used to measure the pressure of gas G in cm of water. (Figure is not drawn to the scale.)

What is the pressure of gas G?
A. 6 cm of water more than the atmospheric pressure
B. 8 cm of water more than the atmospheric pressure
C. 6 cm of water less than the atmospheric pressure
D. 8 cm of water less than the atmospheric pressure
Answer : A

Question. Different weights P, Q and R were hung on a spring as shown in the figure.

Which of the following represents the length of the spring when only weight P is hung on the spring?
A. 7 cm
B. 10 cm
C. 17 cm
D. 22 cm
Answer : B

Question. Which one of the following is a right arrangement?
A. Rolling friction > static friction > sliding friction
B. Sliding friction < static friction < rolling friction
C. Rolling friction > static friction < sliding friction
D. Static friction > sliding friction > rolling friction
Answer : D

Question. The force that is responsible for revolution of the earth around the sun is
A. Electric force
B. Magnetic force
C. Electromagnetic force
D. Gravitational force.
Answer : D

Question. In an experiment to measure the speed of sound in air, a boy stands 40 m away from a wall and bangs two pieces of wood together. At the instant he hears the echo, he bangs them together again. He does this activity 50 times. The time taken for 50 bangs is 12 s. Which calculation gives the speed of sound in air?
A. 12/40 × 50
B. 40x50/12
C. 40x2x50/12
D. 40x2x12/50
Answer : C

Question. A student performed experiments taking similar bulbs and cells, but two different solutions I and II as shown in the figure.

She found that the bulb in the set-up P glows more brightly as compared to that of the set-up Q. You would conclude that
A. Higher current is flowing through the circuit in set-up P as compared to set-up Q
B. Higher current is flowing through the circuit in set-up Q as compared to set-up P
C. Equal current is flowing through both the circuits.
D. The current flowing through the circuits in the two set-ups cannot be compared in this manner.
Answer : A

Question. A plane mirror forms a virtual image. The distance between Mahima and her image in a plane mirror is 10 m. How much distance should she move in order to get the distance of 5 m between herself and her image?
A. 2.5 m away from the mirror
B. 2.5 m towards the mirror
C. 5 m away from the mirror
D. 5 m towards the mirror
Answer : B

Question. Read the given statements and select the correct option.
Statement 1 : When an object is placed between two plane parallel mirrors, then all the images formed are of unequal intensity.
Statement 2 : In case of plane parallel mirrors, only two images are possible.
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 : C

Question. Which coil produces the strongest electromagnet for a given flow of current?
A. A 10 cm coil with 100 turns
B. A 5 cm coil with 200 turns
C. A 10 cm coil with 200 turns
D. A 20 cm coil with 200 turns
Answer : B

Question. According to the given speed- time (v-t) graph, what happens to the distance covered by the car from 0-10 minutes?

A. It goes on increasing.
B. It goes on decreasing.
C. It first increases and then decreases.
D. It first decreases and then increases.
Answer : A

Question. Neha conducted an experiment as shown in the diagram. 

Answer : C

Question. While drinking a soft drink with the help of a straw, the pressure in the straw is _______ and the pressure in the bottle is _______.
A. High, less
B. High, high
C. Less, less
D. Less, high
Answer : D

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

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

Question. Consider the following statements :
I. Natural gas can be supplied to homes and factories through pipes.
II. Natural gas is obtained by fractional distillation of petroleum.
III. Natural gas is a cleaner fuel, on burning it does not produce any ash or smoke.
IV. Natural gas is an exhaustible source of energy like fossil fuels.
The correct statements are
A. I and III only
B. II and III only
C. I and IV only
D. I, III and IV only.
Answer : D

Question. Rishab has arranged the following set-ups to study the process of rusting.

A. (ii) and (iii) only
B. (i) and (ii) only
C. (iii) and (iv) only
D. (i) and (iv) only.
Answer : D

Question. Which of the following statements is incorrect?
A. Gold and silver are the most malleable and ductile metals.
B. All metals are hard and strong.
C. Mercury and gallium are metals which exist in liquid state at room temperature.
D. Most of the metals have high specific gravities.
Answer : B

Question. Match the following columns for the flame of a candle

A. P-(iii), (y); Q-(i), (z); R-(ii), (x)
B. P-(ii), (x); Q-(iii), (y); R-(i), (z)
C. P-(iii), (x); Q-(ii), (z); R-(i), (y)
D. P-(i), (z); Q-(iii), (x); R-(ii), (y)
Answer : C

Question. Following statements are given by four students :
Rashmi : Sodium chloride is an acidic salt whereas washing soda is a basic salt.
Akshi : The aqueous solution of sugar does not change the colour of either red litmus solution or blue litmus solution.
Reema : Tamarind tastes sour whereas baking soda is bitter in taste.
Shristi : Apple juice does not change the colour of red litmus solution.
The incorrect statement(s) is/are given by
A. Reema and Shristi only
B. Rashmi only
C. Akshi and Reema only
D. Akshi and Shristi only.
Answer : B

Question. Read the given statements and select the correct option.
Statement 1 : Bakelite is used for making electric switches and plugs.
Statement 2 : It is a thermosetting polymer and an insulator.
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. Find the incorrect match.
A. CuSO₄ + H₂S → CuS + H₂SO₄ – Double displacement reaction
B. C + 2S → CS₂ – Endothermic reaction
C. NH₄OH + HCl → NH₄Cl + H₂O – Neutralisation reaction
D. Cl₂ + H₂ → 2HCl – Hydrogen is acting as an oxidising agent
Answer : D

Question. Which of the following statements is/are incorrect?
I. Perspex is thermoplastic which is transparent like glass but is much stronger.
II. Nylon thread cannot support more weight as compared to steel wire of same dimensions.
III. Polyester and nylon on burning give smell of burning hair.
IV. Terylene, a synthetic fibre, can be used instead of wool.
A. II, III and IV only
B. II and IV only
C. I only
D. I, II, III and IV
Answer : D

Question. Given below is a list of few chemicals that are used for protection of crops.
(i) Dalapon (ii) Butachlor
(iii) Malathion (iv) Simazine
(v) Disyston (vi) Gammexane
How many of these are used as insecticides?
A. 3
B. 4
C. 2
D. 5
Answer : A

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

A. L could be Pseudomonas that helps in biodegradation of organic pollutants.
B. M could be Vibrio cholerae that causes cholera in human beings.
C. N could be Treponema pallidum that causes syphilis in human beings.
D. O could be Lactobacillus that helps in curdling of milk.
Answer : A

Question. Following are the differences between manures and fertilisers.

Which of the given differences are incorrect?
A. (ii) and (v) only
B. (i), (ii) and (v) only
C. (iii) and (iv) only
D. (i), (iii) and (v) only
Answer : A

Question. Identify the parts of female reproductive system from the given statements and select the correct option.
P : It receives sperms.
Q : Here zygote develops into a baby.
R : Ovum gets fertilised here.
S : It produces female gamete

Answer : B

Question. Refer to the given figure and select the incorrect statement regarding labelled parts W, X, Y and Z.

A. Deficiency of hormone released by W could result in retarded growth of the body.
B. Deficiency of hormone released by X during childhood could cause mental impairment and reduced growth whereas in adults it leads to reduced metabolism.
C. Deficiency of hormone released by Y could negatively affect development of gametes and differentiation of secondary sexual characters in males and females.
D. Deficiency of hormone released by Z may cause a rise in blood sugar level leading to a condition called diabetes mellitus.

Answer : D

Question. Select the incorrect statement.
I. Sulphur dioxide gas combines with haemoglobin of blood and prevents transport of oxygen by it.
II. Methane, nitrous oxide and water vapour present in atmospheric air contribute to global warming.
III. Lead emitted by automobile exhaust could cause brain damage.
IV. Oxides of sulphur and nitrogen present in air could affect lungs.
A. I only
B. I and IV only
C. I, II and IV only
D. I and III only
Answer : A

Question. Identify P, Q, R and S in the given Venn diagram and select the incorrect option regarding them.

A. P could be a colourless organelle that helps to store reserve food in the form of lipids, carbohydrates and proteins.
B. Q could be an organelle that is involved in formation of spindle during cell division.
C. R could be an organelle that contains genetic material organised as DNA along with proteins to form chromosomes.
D. S could be an organelle that produces energy currency of the cell, ATP through cellular respiration.
Answer : B

Question. Match column I with column II and select the correct option from the given codes. (There can be more than one match for column I.)
      Column I                  Column II
(a) Green algae            (i) Gelidium
(b) Red algae               (ii) Chlamydomonas
(c) Blue-green algae    (iii) Nostoc
(d) Brown algae           (iv) Polysiphonia
                                    (v) Ulothrix
                                    (vi) Anabaena
                                    (vii) Sargassum
                                    (viii) Fucus
A. (a)-(ii, v), (b)-(i, vi), (c)-(iii, iv), (d)-(vii, viii)
B. (a)-(ii, v), (b)-(i, iv), (c)-(iii, vi), (d)-(vii, viii)
C. (a)-(ii, vii), (b)-(i, iv), (c)-(iii, vi), (d)-(v, viii)
D. (a)-(ii, v), (b)-(iii, iv), (c)-(i, vi), (d)-(vii, viii)
Answer : D

Question. Identify W, X and Y in the given figure and select the incorrect option regarding them.

A. X is the chamber where partially chewed food is stored temporarily.
B. W is the chamber which is often referred to as true stomach which leads to small intestine.
C. X is the chamber where anaerobic bacteria help in breakdown of cellulose.
D. Y is the chamber where protein is digested with the help of enzymes.
Answer : D

Question. Refer to the given experimental set-ups a and b and select the correct option regarding gases X and Y.

A. X could be a gas that causes global warming.
B. Y could be a gas that is fixed in carbohydrate by plants during photosynthesis.
C. X could be a gas that is used in fire extinguishers.
D. Y could be a gas that is present in largest proportion in atmospheric air.
Answer : B

Question. Refer to the given figures showing seeds/fruits of three different plants.

Select the option which contains plants that can replaceX, Y and Z, respectively based on the mode of dispersal of their seeds.
        X                     Y                    Z
A. Lotus             Beans          Calotropis
B. Castor           Coconut       Acer
C. Dandelion     Balsam        Urena
D. Mango          Cotton          Maize
Answer : B

Question. Which of the following graphs shows the likely relationship between the percentage of pollution to the population of people in a particular town?

Answer : D

ACHIEVERS SECTION

Direction (Q. No. a and b) : Read the given passage and select the correct option for the following questions.

Figures show a negatively charged rod, an uncharged metal sphere on an insulating stand and a connection to the earth.

The given apparatus is used to charge the metal sphere positively. At the end of the charging process, the metal sphere has a charge of 15 C. The charging process takes 5 s.

Question a. Charging of the metal sphere involves different steps as shown below.

 
Arrange these steps in correct order to charge the metal sphere.
A. I, II, III, IV
B. II, IV, III, I
C. II, IV, I, III
D. I, III, II, IV
Answer : B

Question b. If average current is defined as net charge flowing per unit time, then find the average current in the charging process. 
A. 15 C × 5 s
B. 5 s/15 C
C. 15x2C/5s
D. 15C/5s
Answer : C

Question. Observe the given figure carefully.

Select the correct statement(s) from the following.
I. In beaker ‘P’, blue colour of solution changes to green colour.
II. In beaker ‘Q’, no reaction takes place.
III. In beaker ‘R’, if ‘Y’ is aluminium then reaction will take place.
IV. In beaker ‘R’, if ‘Y’ is tin then reaction will take place.
A. I only
B. II and IV only
C. I and III only
D. I, II, III and IV
Answer : A

Question. Refer to the given flow chart and select the correct option regarding P, Q, R and S.

A. P could be wild buffalo whereas Q could be chinkara.
B. Q could be golden langur whereas S could be passenger pigeon.
C. R could be Hawaiian crow whereas S could be Asiatic lion.
D. Q could be Asiatic wild ass whereas R could be Tibetan antelope.
Answer : D

Question. The given graph shows the blood examination report of Mr X.

What can be inferred about the condition of Mr X?
A. Mr X is anaemic as his RBC count is slightly more than the normal reference range.
B. Mr X lives in plains and has recently gone to some higher altitude place where he has successfully acclimatised with the prevailing conditions.
C. Mr X is suffering from an infection like dengue as his platelet count is very high.
D. Mr X has delayed blood clotting and continues to bleed even from a minor cut.
Answer : A