CBSE Class 8 Science NSO Olympiad MCQs with Answers Set D

LOGICAL REASONING

Question. If it is possible to make a meaningful word with the 1st, 12th, 15th and 21st letters of the given arrangement, then which will be first letter of the word so formed?
If no such word can be formed, give X as the answer and if more than one such word can be formed, give P as the answer.
E S G B D L U N K H W A C Z T V X F I J M O Q Y P R
A. M
B. T
C. X
D. P
Answer : D

Question. Two positions of a dice are shown below. How many dots will be on the top when 2 dots are at the bottom?

A. 6
B. 5
C. 1
D. 4
Answer : C

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

Answer : B

Question. If '+' is called '×', '–' is called '÷', '×' is called '–' and '÷' is called '+', then the value of 16 ÷ 64 – 8 × 4 + 2 is _____.
A. 12
B. 16
C. 18
D. 24
Answer : B

Question. Study the following information carefully:
(i) B5D means B is the father of D.
(ii) B9D means B is the sister of D.
(iii) B4D means B is the brother of D.
(iv) B3D means B is the wife of D.
Which of the following means F is the mother of K?
A. F3M5K
B. F5M3K
C. F9M4N3K
D. F3M5N3K
Answer : A

Question. In the given diagram, rectangle represents men, triangle represents educated, circle represents urban and square represents government employees.

Which of the following represents a man who is urban as well as government employee but not educated ?
A. 7
B. 13
C. 10
D. 6
Answer : D

Question. Select the correct mirror image of the given combination of letters & numbers, if the mirror is placed vertically to the left.

Answer : B

Question. Persons X, Y, Z and Q live in red, green, yellow or blue coloured houses placed in sequence on a street. Z lives in a yellow house. The green house is adjacent to the blue house. X does not live adjacent to Z. The yellow house is in between the green and red houses.
The colour of the house X lives in is ______.
A. Blue
B. Green
C. Red
D. Data inadequate
Answer : A

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

Answer : C

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

Answer : C

SCIENCE

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 : Moisture increases the pressure.
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. A student has a large tank of water in which he wants to set up a convection current. Which of the following actions will help him to do it?

A. Cooling at Q
B. Cooling at R
C. Heating at P
D. All of these
Answer : D

Question. A narrow beam of white light is passed through a glass prism as shown in the figure.

Which of the following is the correct order of colours emerging from the prism?
        P            Q              R
A. Red        Blue         Green
B. Red        Green       Blue
C. Blue       Green       Red
D. Blue       Red          Green
Answer : B

Question. The diagram shows a method to magnetise an iron nail. In which diagram will the iron nail become an induced magnet?

Answer : C

Question. Match the column I with column II and select the correct option from the given codes.
          Column I                        Column II
(a) Limiting friction             (i) Self adjusting force
(b) Static friction                (ii) Less than sliding friction
(c) Dynamic friction           (iii) Maximum value of static friction
(d) Rolling friction              (iv) Less than limiting friction
A. (a) – (ii), (b) – (i), (c) – (iv), (d) – (iii)
B. (a) – (iii), (b) – (i), (c) – (ii), (d) – (iv)
C. (a) – (iv), (b) – (ii), (c) – (i), (d) – (iii)
D. (a) – (iii), (b) – (i), (c) – (iv), (d) – (ii)
Answer : D

Question. A floor has a maximum loading capacity of 5 kN m^–2.
Which of the following is allowed on this floor?
(Take g = 10 N kg^–1)
A. An elephant weighing 50 kN stands on 4 legs with each foot covering 400 cm2 of the floor.
B. A 50 kg lady wears a pair of high heel shoes, each shoe has a contact area of 9 cm2 with the floor.
C. A 100 kg washing machine stands on a surface area of 6500 cm2.
D. A designer’s table weighing 1000 N stands on 3 legs, each leg has a contact area of 0.1 cm² with the floor.
Answer : C

Question. The diagram shows the melting and boiling points of four different substances. Which substance is in solid state at 0°C and liquid state at 1400°C ?

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

Question. A vessel contains two plane mirrors at right angles to each other as shown here. If the vessel is filled with water, then the total deviation in the ray incident normally is

A. 0°
B. 45°
C. 90°
D. 180°
Answer : D

Question. Which of the following options is true regarding the number of moons of the given planets?
A. Mars < Earth < Uranus < Neptune < Jupiter
B. Earth < Mars < Jupiter < Uranus < Neptune
C. Earth < Mars < Neptune < Uranus < Jupiter
D. Jupiter < Earth < Mars < Neptune < Uranus
Answer : C

Question. An iron block of dimensions 5 cm × 10 cm × 15 cm has to be pushed along the floor. The force required will be minimum when the surface in contact with ground is
A. (10 cm × 15 cm) surface
B. (5 cm × 15 cm) surface
C. (10 cm × 5 cm) surface
D. Force is same for all surfaces.
Answer : D

Question. The given diagram shows the night sky in which stars are visible. Identify the star X, and the constellation Y from the figure.

        X                     Y
A. Orion              Cassiopeia
B. Sirius              Orion
C. Pole star        Sirius X Y
D. Pole star        Orion
Answer : B

Question. For the velocity-time graph shown here, the distance covered by the body in last two seconds of its motion is what fraction of the total distance covered by it in six seconds?

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

Question. Two identical neutral light conducting balls suspended by insulating threads touch each other as shown. 

Answer : C

Question. Which of the following statements are true?
(i) Beautiful patterns formed in a kaleidoscope is due to irregular reflections.
(ii) Two plane mirrors when placed parallel to each other give infinite number of images.
(iii) Real image is always inverted.
(iv) Virtual image can be taken on a screen.
A. (i) and (ii)
B. (ii) and (iii)
C. (iii) and (iv)
D. (i) and (iv)
Answer : B

Question. The second's hand of a watch is 2 cm long. The speed of the tip of second's hand is
A. 0.21 cm s^–1
B. 2.1 cm s^–1
C. 21 cm s^–1
D. 0.021 cm s^–1
Answer : A

Question. Rohit has performed an activity to test whether the following materials conduct electricity or not by putting them in the circuit, one at a time as shown in the figure.

         X                 Y
A. 1, 3, 4, 6       2, 5
B. 1, 5, 6           2, 3, 4
C. 1, 3, 6           2, 4, 5
D. 2, 3, 4, 5       1, 6
Answer : A

Question. Fill in the blanks by choosing an appropriate option.
Each cell in our body contains an acid, the (i). It controls every feature of the body such as our looks, colour of our eyes, our height, etc. Proteins that build part of our cells are also made of (ii) . The fats in our body contain (iii) .
(i), (ii) and (iii) respectively are
A. Amino acids, deoxyribonucleic acid, fatty acids
B. Deoxyribonucleic acid, fatty acids, amino acids
C. Deoxyribonucleic acid, amino acids, fatty acids
D. Fatty acids, deoxyribonucleic acid, amino acids.
Answer : C

Question. Find the incorrect match.
A. Haemoglobin – Magnesium
B. Fertilisers – Nitrogen and phosphorus
C. Chlorophyll – Iron
D. Both A and C
Answer : D

Question. Read the given statements and select the correct option.
Statement 1 : Bakelite is used for making electrical switches and handles of various utensils.
Statement 2 : Bakelite is a good conductor of heat and electricity.
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. Select the incorrect statements among the following.
(i) Bitumen is used for metalling the roads.
(ii) Some inexhaustible natural resources like coal, petroleum and natural gas formed from the dead remains of living organisms are known as fossil fuels.
(iii) Many useful substances are obtained from coal so, it is also called ‘Black gold’.
(iv) Natural gas is used as a starting material for the manufacture of a number of chemicals and fertilisers.
A. (i) and (ii)
B. (ii) and (iii)
C. (ii) and (iv)
D. (i), (ii) and (iv)
Answer : B

Question. Match the column I with column II and select the correct option from the given codes.
        Column I                   Column II
P. Zinc carbonate      (i) turns methyl orange red
Q. Citric acid            (ii) treats acidic soil
R. Slaked lime         (iii) potassium hydroxide
S. Soap                   (iv) remedy for ant's bite
     P        Q        R        S
A. (i)      (iii)      (iv)      (ii)
B. (ii)     (iv)      (iii)      (i)
C. (iv)    (i)        (ii)      (iii)
D. (iii)    (ii)       (iv)      (i)
Answer : C

Question. Observe the given Venn diagram carefully.

1 – Extraction of metal from its oxide using electricity
2 – Burning of a candle
3 – Sublimation of naphthalene balls X and Y respectively are
A. Physical and chemical changes
B. Chemical and physical changes
C. Both chemical changes
D. Both physical changes.
Answer : A

Question. Water is not a suitable fire extinguisher to douse the fires involving oil and petrol because
A. Water may conduct electricity
B. Water is heavier than oil
C. Water cannot be stored at high pressure in cylinders
D. Water is lighter than oil.
Answer : B

Question. X, Y and Z are three methods of weeding. X can be done by ploughing, harrowing etc. Y involves the use of chemicals whereas Z employs biological agents to control weeds.
Identify X, Y and Z and select the correct option regarding this.
A. In small fields, X method involves the use of trowel or hoe which is time consuming and involves a lot of labour.
B. Y method involves the use of poisonous chemicals like metachlor which kill the weeds and may affect the health of farmers and all the consumers.
C. Z method is a safer method to kill weeds as it employs insects which feed on weeds thereby checking their growth and has no side effects on the crop plant and its consumers.
D. All of these
Answer : D

Question. Which of the following statements is incorrect regarding Biosphere Reserve?
A. Biosphere Reserves are multipurpose protected areas meant for conserving genetic diversity, ecosystems and landscapes without uprooting the local people.
B. Each Biosphere Reserve supports education and research in various ecological aspects of the ecosystem.
C. Ample human activities like cultivation, recreation, forestry etc., are allowed in the core zone of a Biosphere Reserve.
D. A Biosphere Reserve may include other protected areas such as National Parks.
Answer : C

Question. The given picture shows a set-up at the start of an experiment, X and after a few days, Y. The change observed in set up Y is due to

A. Upward movement of food getting blocked
B. Downward movement of food getting blocked
C. Upward movement of water getting blocked
D. Downward movement of water getting blocked.
Answer : B

Question. Use the given dichotomous key and select the correct option.
I. (a) They are mostly single-celled organisms. - Go to II (a)
(b) They are classified on the basis of shape. - Go to II (b) and III (b)
II. (a) They live together in colonies of millions. - Go to III(a)
(b) The rod shaped are called P .
III. (a) They reside in our intestine and help in the process of digestion. Q 
(b) The comma-shaped and spherical are respectively called R and S .
          P                 Q                         R              S
A. Spirillum     Amoeba                Coccus      Vibrio
B. Vibrio         Streptococcus       Spirillum    Coccus
C. Bacillus      Plasmodium          Coccus      Vibrio
D. Bacillus      E.coli                     Vibrio         Coccus
Answer : D

Question. Refer to the given figure and select the incorrect statement(s).
(i) The part labelled P is found in plant cell only.
(ii) The part labelled Q is cell wall, which provides rigidity to a plant cell.
(iii) The part labelled R is the controlling centre.
(iv) The part labelled R gets its shape from part labelled P.

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

Question. Refer to the given diagram with its parts labelled as P, Q, R and S. Which of the following statements is incorrect regarding this?

A. In Q, the sperm and ovum fuse to form zygote.
B. Development of foetus takes place in S.
C. R is the site of implantation of embryo.
D. One of the functions of P is to control secondary sexual characters.
Answer : B

Question. Which of these is a behavioural adaptation?
A. A hognose snake pretends as dead to trick the predator.
B. A frog’s light-coloured belly makes it harder for a predatory fish to see it against sunlight on the water surface.
C. The scarlet king snake looks very much like the poisonous coral snake.
D. A treehopper on a leaf or twig resembles a thorn.
Answer : A

Question. Study the given flow chart and identify P, Q and R.

Answer : A

Question. Rahul conducted an experiment as shown here.

Which of the following statements is correct regarding this?
A. Hydrilla plant cannot photosynthesise as CO₂ is not available to the plant.
B. NaHCO₃ present in the water absorbs all CO₂ dissolved in it.
C. Sunlight cannot reach the plant properly and hence photosynthetic rate of the plant is affected.
D. The bubbles produced in the water within test-tube are mainly of oxygen gas.
Answer : D

Question. Read the given paragraph.
The female silk moth lays hundreds of tiny eggs at a time. The eggs are cooled to a suitable temperature to hatch. The tiny silkworms or caterpillars are kept in clean bamboo trays along with neem leaves. The caterpillars feed continuously and undergo moulting nine times. Then they stop eating and are ready to enter pupal stage. They spin cocoon around themselves which takes around eight days.
Some of the words have been italicised. Select the correct option regarding them.
A. Cooled should not be replaced as it is correctly mentioned.
B. Neem should be replaced by pomegranate.
C. Nine should be replaced by four.
D. Eight should be replaced by twenty.
Answer : C

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

       P       Q         R         S        T
A. a, 3     b, 2     b, 1     b, 4     b, 3
B. b, 3     a, 1     a, 2     b, 3     b, 4
C. b, 4     a, 2     a, 1     a, 3     a, 4
D. a, 2     b, 1     b, 3     b, 2     b, 4
Answer : B

45. Rita set up an experiment as shown here.

What will happen to the drop of fluid in the capillary tube over the next few hours?
A. It will move away from the test tube because of oxygen output by the seeds.
B. It will move towards the test tube because of carbon dioxide intake by the seeds.
C. It will move towards the test tube because of oxygen intake by the seeds.
D. It will not move, because carbon dioxide intake and oxygen output are equal.
Answer : C

ACHIEVERS SECTION

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

The given figure shows the electroplating of copper over a flower vase made of iron. It is done by the process of electrolysis.

Question a. Identify X, Y and Z from the figure.
        X                       Y                         Z
A. Anode             Cathode            Electrolyte
B. Cathode          Anode               Electrolyte
C. Electrolyte      Cathode            Anode
D. Cathode         Electrolyte         Anode
Answer : B

Question b. During electrolysis, positively charged _______ ions move towards flower vase and negatively charged _______ ions move towards copper rod.
A. Sulphate, Copper
B. Copper, Sulphide
C. Copper, Sulphate
D. Sulphate, Sulphide
Answer : C

Question. Read the given statements each with one or two blanks in it.
P. (i) allows water, minerals and some other necessary substances to move across cell.
Q. The liquid in the nucleus is called (ii) in which are suspended thread-like structures called (iii) .
R. (iv) are called powerhouse of cell whereas (v)  are called kitchens of cell.
S. (vi) help to destroy old cell structures and (vii) take part in protein synthesis.
Select the option which correctly fills some of the blanks in these statements.
A. (i)-Cell wall, (ii)-Genes, (v)-Centrosome
B. (ii)-Nucleoplasm, (iv)-Mitochondria, (vi)-Lysosomes
C. (iii)-Plastids, (vi)-Lysosomes, (vii)-Ribosomes
D. (v)-Chloroplasts, (vi)-Centrosome, (vii)-Endoplasmic reticulum
Answer : B

Question. Each of the given beakers contains two metal strips of same size fastened together and immersed in hydrochloric acid.

After 5 minutes, amount of Q ions formed is greater than P ions in beaker 1, S ions is greater than R ions in beaker 2, R ions is greater than Q ions in beaker 3, and T ions is greater than S ions in beaker 4. 
Correct order of reactivity of these metals is
A. P > Q > R > S > T
B. R < P < T < S < Q
C. T > R > Q > P > S
D. P < Q < R < S < T
Answer : D

Question. The given graph shows changes in levels of two factors X and Y present in a river due to run-off pollution.

Which of the following statements is correct regarding this?
A. X could be an aquatic plant population whereas Y could be a fish population.
B. X could be dissolved oxygen in river whereas Y could be a bacterial population.
C. X could be dissolved oxygen in river whereas Y could be a fish population.
D. X could be a bacterial population whereas Y could be an aquatic plant population.
Answer : B