CBSE Class 8 Science NSO Olympiad MCQs with Answers Set B

LOGICAL REASONING

Question. Select a figure from the options in which Fig. (X) is exactly embedded as one of its part.

Answer : A

Question. Three positions of a dice are shown below. What is the number opposite to the number 1 ?

A. 2
B. 3
C. 5
D. 6
Answer : D

Question. Vijay walks 10 kilometres towards North. From there, he walks 6 kilometres towards South. Then, he walks 3 kilometres towards East. How far and in whichdirection is he now with reference to his startingpoint?
A. 5 kilometres West
B. 5 kilometres North-East
C. 7 kilometres East
D. 7 kilometres West
Answer : B

Question. Find the mirror image of the Fig. (X), if the mirror is placed vertically to the left.

Answer : B

Question. If in a code REQUEST is written as S2R52TU, then how will ACID be written in that code?
A. BDJE
B. 1394
C. B3J4
D. 1D3E
Answer : D

Question. 8 is related to 81 in the same way as 64 is related to ________.
A. 125
B. 137
C. 525
D. 625
Answer : D

Question. Select a figure from the options which will continue the given series.

Answer : C

Question. Study the series carefully and answer the question that follows.
∂ = b F 2 * K S 7 5 # $ P L V 8 @ M 6 ↑ Q G
© 9 3 & T Y £
What will come in place of question mark?
If '= → 2', 'K → #' and 'P → M', then '↑ → ?'.
A. 3
B. T
C. 9
D. &
Answer : D

Question. In first row, a series is given which follows a specific pattern. The second row has a series, similar to the first series but only first element of this series is given. Identify the pattern and answer the question that follows.
6     18      36      108      216      648
2     a         b        c          d          e
What will come in place of e ?
A. 482
B. 344
C. 216
D. 420
Answer : C

Question. In the given Venn diagram, find the region representing persons who are educated and employed but not confirmed in job.

A. d
B. e
C. b
D. a, b
Answer : C

Question. Which of the following figures will complete the figure matrix ?

Answer : D

Question. A is the brother of B. C is married to D. If C is the nephew of B, how is A related to D?
A. Father-in-law
B. Mother-in-law
C. Son-in-law
D. Daughter-in-law
Answer : A

Question. Select a pair of figures which satisfies the same conditions of placement of dots.

A. PR
B. QS
C. PS
D. QT
Answer : A

Question. Which of the following options will exactly make up the key Fig. (X) ?

Answer : C

Question. A sheet of paper is folded in a particular manner and a punch is made. Select a figure from the options which will closely resemble the unfolded form of given sheet.

Answer : B

SCIENCE

Question. The pressure of the water near the bottom of the wall forming a dam does not depend on ______.
A. The depth of the water
B. The cross-sectional area of the reservoir
C. Density of water
D. Atmospheric pressure
Answer : B

Question. When the tension in the string of a guitar is increased, but other factors remain unchanged, the sound produced ________.
A. Is louder
B. Has higher pitch
C. Has longer wavelength
D. Travels faster
Answer : B

Question. A windmill is pushed by four external forces as shown in the given figure. The force F required to make the windmill stand still is

A. 10 N
B. 13 N
C. 15 N
D. 18 N
Answer : B

Question. The given diagram shows water being heated in a tin can. A thermometer hangs directly above it. In which way, does the thermal energy from the heat source reach the thermometer?

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

Question. A person X is facing a plane mirror which is fixed. While another person Y is running towards person X from behind at a speed of 2 m s^–1  as shown in the given figure. How fast does person Y seem to be running towards person X in the mirror ?

A. 2 m s^–1 
B. 3 m s^–1 
C. 4 m s^–1 
D. 6 m s^–1 
Answer : A

Question. A positively charged oil drop is suspended in the air by two charged plates as shown in the given figure.

What will happen to the oil drop if the positive charge in it decreases?
A. The oil drop will move randomly.
B. The oil drop will move upwards.
C. The oil drop will move downwards.
D. The oil drop will remain stationary.
Answer : C

Question. When electrodes are immersed in water and electricity is passed, then the bubbles formed on the negative terminal is
A. Oxygen
B. Hydrogen
C. Carbon dioxide
D. Nitrogen
Answer : B

Question. Arrange the following planets in increasing order of time required to complete one rotation around Sun.
(i) Earth (ii) Uranus
(iii) Mars (iv) Jupiter
A. (i), (ii), (iii), (iv)
B. (i), (iii), (iv), (ii)
C. (iv), (iii), (ii), (i)
D. (ii), (iii), (i), (iv)
Answer : B

Question. Two persons P and Q are standing at a distance of 100 m from a high wall as shown in the given figure.

When P gives a clap, the time interval between the two (direct and reflected) sounds heard by Q is 0.2 s.
If the speed of sound is 340 m s–1, then the distance d between P and Q is

A. 160 m Wall
B. 260 m
C. 290 m
D. 320 m
Answer : B

Question. The speed-time graphs for three vehicles X, Y and Z are shown.
If x, y and z are the distances travelled by X, Y and Z respectively in 8 s, then which of the following comparisons is correct ?
A. x > y = z
B. x > y > z
C. x = y < z
D. x < y < z
Answer : A

Question. Which of the following objects experience balanced forces?
A. A ball dropping vertically.
B. A car accelerating uniformly from rest.
C. A trolley moving at a constant velocity down an inclined plane.
D. A plane flying in a circle with constant speed.
Answer : C

Question. Spoons of different materials are used to stir a hot drink. Which of the following spoons will heat up the fastest?
A. Plastic spoon
B. Steel spoon
C. Glass spoon
D. Wooden spoon
Answer : B

Question. When we remove polyester or woolen cloth in dark, we can see spark and hear a cracking sound. These are due to ________.
A. Static electricity
B. Current electricity
C. Movement of charges
D. None of these
Answer : A

Question. Observe the given experimental set-up and identify the gas ‘X’ and its characteristics.

I. It is carbon dioxide.
II. It is sulphur dioxide.
III. It does not support combustion.
IV. It is acidic in nature.
A. II and IV
B. I, III and IV
C. I and III
D. II, III and IV
Answer : B

Question. Namita categorised the different elements as shown below :

Which of the characteristics is not correctly matched by Namita?
A. a, c and e
B. a, b, d and e
C. b, c and d
D. All are correct
Answer : C

Question. Read the given statements carefully.
P : I am the most common fire extinguisher but not suitable for oil, petrol and electrical fires. I am heavier than oil and also, conduct electricity.
Q : I am an excellent fire extinguisher and most suitable for oil, petrol and electrical fires. I also, form a blanket around the fire and bring down the temperature of the fuel.
Identify P and Q.
      P             Q
A. CO₂         H₂O
B. H₂O        CO
C. O₂          CO₂
D. H₂O        CO₂
Answer : D

Question. Renuka, a science teacher performed the following activity to prove that air is necessary for combustion.

She asked the students to observe the flame of lighted candles placed under the glass chimneys carefully.
What were the correct observations

Answer : C

Question. Fill in the blanks.
Raghav used excessive chemical fertilisers during farming which makes the soil (i) . He added
(ii) to increase the production of crops. Rahul used excessive substances to neutralise the factory wastes near his field. As a result, the soilof his field became too (iii) which he treated with (iv)

Answer : C

Question. Identify Y and Z in the given Venn diagram.

            Y                                     Z
A. Oxalic acid                  Milk of magnesia
B. Soap                           Tartaric acid
C. Window cleaner         Ascorbic acid
D. Milk of magnesia       Oxalic acid
Answer : D

Question. Match the Column-I with Column-II and select the correct option given below.
    Column-I                   Column-II
a. Coal tar                 (i) Metalling the roads
b. Petrol                   (ii) Manufacture of steel
c. Coal gas              (iii) Source of heat
d. Bitumen              (iv) Vaseline
e. Coke                   (v) Naphthalene balls
f. Paraffin wax        (vi) Dry cleaning
A. a-(v), b-(vi), c-(iii), d-(i), e-(ii), f-(iv)
B. a-(i), b-(iv), c-(iii), d-(ii), e-(v), f-(vi)
C. a-(iii), b-(v), c-(i), d-(iv), e-(ii), f-(vi)
D. a-(iv), b-(i), c-(vi), d-(iii), e-(v), f-(ii)
Answer : A

Question. Which of the following statements about the characteristics of organelles are correct?
(i) Mitochondria contain their own DNA.
(ii) Lysosomes contain many anabolic enzymes.
(iii) Secretory liver cells have abundant number of RER.
(iv) Ribosomes are always found attached to the Golgi apparatus.
A. (i) and (iii)
B. (i) and (ii)
C. (i), (ii), (iii) and (iv)
D. (i), (ii) and (iv)
Answer : A

37. Digestion of food involves breaking down of food components into smaller molecules by enzymes. These enzymes are active only at certain hydrogen ion concentrations. As a result, certain food combinations can facilitate or retard the process of digestion. Of the following combinations, one that can result in very efficient digestion is ______.
A. Meal with high proteins and acid fruits
B. Meal with high starch and high proteins
C. Meal with high starch and acid fruits
D. Meal with high fat and high proteins
Answer : A

Question. Body temperature of some animals changes with that of atmosphere while some animals have adapted to maintain constant body temperatures. Advika investigated this fact using three animals X, Y and Z and obtained the given graph. Which of these options correctly identifies X, Y and Z ?

       X                             Y                Z
A. Frog                     Lizard          Rabbit
B. Lizard                   Cobra          Rabbit
C. Salamander         Crow           Cow
D. Crow                    Bear            Frog
Answer : D

Question. Run-off pollution of a particular river resulted from overuse of chemical fertilizers by a nearby farm.
Which of the following graphs correctly shows the resulting changes in levels of oxygen and bacteria in this river?

Answer : A

Question. The given figure represents the location of various endocrine glands in human body. 
Identify the glands marked as P, Q, R, S and T and select the incorrect statement regarding these.

A. Gland P secretes the hormone thyroxine, which regulates growth and metabolism.
B. Gland Q secretes the hormones corticosteroids and adrenaline, which regulate breathing, heart rate, carbohydrate metabolism and mineral balance.
C. Glands S and T secrete the hormones which control secondary sexual characters in females and males respectively.
D. Gland R secretes the hormone insulin, whose increased concentration leads to diabetes.
Answer : D

Question. Read the given statements and select the correct option.
Statement 1 : Hotspots are specific regions of megabiodiversity nations with large number of endemic species.
Statement 2 : Endemic species are often threatened due to the introduction of exotic species from some other geographical area.
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. Statement 2 is true and statement 1 is false.
Answer : B

Question. Select the incorrect statement from the following.
A. Synthetic fibres have little or no absorbency, although several of them do absorb oil.
B. Wool fibre is harmed by acids including mild acids like vinegar.
C. Cellulose fibres continue to glow after they are removed from the flame.
D. Cotton fibres, linen and other cellulose fibres are quiet heat resistant and can be boiled safely.
Answer : B

Question. Refer to the given diagram which shows a cross section of the stem and select the correct option.

A. If we put a plant in red water for sometime, the colour would then appear in the part X.
B. On girdling, swelling occurs above the girdled part due to the discontinuity of part Y.
C. Conduction of water and organic solutes occurs through part Y.
D. Conduction of products of photosynthesis occurs through part X.
Answer : D

Question. Tarun sets up a plant as shown in the figure.
After a few days, he observed upward growth in the roots of the plant.

Based on his observations what can you conclude?
A. Soil X is clayey while soil Y is loamy.
B. Soil X is sandy while soil Y is clayey.
C. Soil X is loamy while soil Y is sandy.
D. It is not possible to tell.
Answer : C

Question. Read the given passage in which some words are italicised.
Agriculture has become more efficient with the advent of modern technology. Modern tractor driven ploughs are faster and better. Seed drills used today combine 5-6 traditional seed drills. Thus, they are faster and ensure sowing seeds at proper depth of 20-25 cm.
Modern irrigation methods have also been developed which reduce water wastage. Drip irrigation is less expensive method particularly useful for soils with low water retention capacity. Sprinklers are more suited for uneven lands and sandy soils.
Some of these italicised words are put incorrectly.
Find out them and select the correct option.
A. Less expensive should not be replaced as it is
correctly mentioned.
B. 20-25 cm should be replaced by 10-15 cm.
C. Low should be replaced by high.
D. Uneven lands should be replaced by plain lands.
Answer : B

ACHIEVERS SECTION

Direction : (Q. No. a and b) Refer the given passage and answer the following questions.

A metre ruler is held vertically in front of a plane mirror of length 15 cm as shown in the given figure.
A student peeps through a hole at the 40 cm mark.

Question a. The range of the scale of the metre ruler that can be seen is
A. 10 cm to 40 cm
B. 15 cm to 45 cm
C. 20 cm to 50 cm
D. None of these
Answer : C

Question b. If the hole is at 80 cm mark of the scale, then the range of the metre ruler that can be seen in the mirror is
A. 10 cm to 40 cm
B. 20 cm to 50 cm
C. 30 cm to 60 cm
D. None of these
Answer : D

Question. Anuj has performed an experiment to compare the strength of different fibres.
He arranged the set-up as shown in figure :

Arrange the threads in order of their increasing strength.
A. Nylon < Silk < Cotton
B. Silk < Cotton < Nylon
C. Cotton < Nylon < Silk
D. Cotton < Silk < Nylon
Answer : D

Question. Swati was studying growth of yeast under different conditions of environment. She plotted two graphs but forgot to label the X axes of the graphs. Analyse the given graphs and select the correct option.

A. The environmental factor studied in graph P can be pH and in graph Q can be temperature.
B. The environmental factor studied in graph P can be temperature and in graph Q can be sugar concentration in medium.
C. The environmental factor studied in graph P can be temperature and in graph Q can be pH.
D. The environmental factor studied in the graph P can be sugar concentration in medium and in graph Q can be pH.
Answer : B

Question. Refer the given key to identify the organisms P, Q, R, S, T and U and select the correct option.
1. (i) Somatic cells carry out propagation - Go to 2.
(ii) Germ cells carry out propagation - Go to 3.
2. (i) Single cell division forms new organism - P
(ii) Multiple cell divisions occur - Go to 4.
3. (i) Fertilization occurs outside parent's body - Q
(ii) Fertilization occurs inside parent's body - Go to 5.
4. (i) Each cell produced after division produces new organism - R
(ii) All the cells together form a new organism - S
5. (i) Embryonic development occurs outside parent's body - T
(ii) Embryonic development occurs inside parent's body - U
A. P can be yeast, Q can be chamaeleon.
B. R can be Plasmodium, S can be Hydra.
C. T can be duck-billed platypus, U can be ostrich.
D. P can be yeast, U can be spiny ant eater.
Answer : B