CBSE Class 10 Science NSO Olympiad MCQs with Answers Set H

LOGICAL REASONING

Question. Find the missing term in the given series.
APZ, BRY, DTW, GVT, KXP, ___ ?__
A. PZK
B. PZL
C. OZK
D. OYL
Answer : A

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

Answer : C

Question. Two positions of a dice are shown. Find the numberoppo site to number 3.

A. 6
B. 5
C. 2
D. 1
Answer : C

Question. If > stands for +, < stands for –, + stands for ÷, ∧ stands for ×, – stands for =, × stands for > and = stands for <, then which of the following options is correct?
A. 18 > 12 + 4 × 7 > 8 ∧ 2
B. 31 > 1 < 2 = 4 > 6 ∧ 7
C. 29 < 18 + 6 = 36 + 6 ∧ 4
D. 32 > 6 + 2 = 6 < 7 ∧ 2
Answer : B

Question. How many 2's are there in the given arrangement, each of which is not immediately preceded by a perfect square and followed by an odd number?
6 4 2 5 2 8 2 9 2 1 3 8 6 2 1 2 5 8 6 1 2 4 2 5
A. 4
B. 3
C. 2
D. 5
Answer : C

Question. A set of three figures X, Y and Z showing a sequence of folding of a piece of paper is given. Fig. (Z) shows the manner in which the folded paper has been cut.
Select a figure from the options which would most closely resemble the unfolded form of Fig. (Z).

Answer : A

Question. There is a certain relationship between figures (1) and (2). Establish the similar relationship between figures (3) and (4) by selecting a suitable figure from the given options which will replace the (?) in figure (4).

Answer : B

Question. In a certain code language,
1. pod na joc means very bright boy;
2. tam nu pod means the boy comes;
3. nu per ton means keep the doll;
4. joc ton su means very good doll.
Which of the following means good in that language?
A. su
B. joc
C. ton
D. pod
Answer : A

Question. A word arrangement machine, when given a particular input, rearranges it following a particular rule. The following is the illustration of the input and the steps of arrangement:
Input : top the name good for is there
Step I : is top the name good for there
Step II : is for top the name good there
Step III : is for the top name good there
Step IV : is for the top good name there
Step IV is the last step for this input.
As per the rules followed in the above steps, which of the following is the last step of the given input?
Input : if there was no good man
A. V
B. III
C. IV
D. Cannot be determined
Answer : C

Question. Which of the following options will complete the pattern given in Fig. (X) 

Answer : B

SCIENCE

Question. A constant force is acted on a body which is initially at rest on a smooth track. The force acts for a short time interval t, and causes the body to move at a certain final speed. What is the time interval required to move the same body when the force is reduced by half so that the body can move at the same final speed?
A. t
B. 2t
C. t/2
D. 4t
Answer : B

Question. Five coils, each having the same resistance are joined according to the given circuit diagram.

The equivalent resistance between points P and Q is 1 Ω. Then the resistance of each coil will be
A. 1 Ω
B. 4 Ω
C. 1/7 Ω
D. 7/4 Ω
Answer : D

Question. A cube of side 1 m has a mass of 7500 kg before a through hole of diameter 50 cm is drilled on it. The hole is then completely filled with cement of density 3.2 g cm^–3. What is the density of the composite object?
A. 4320 kg m^–3
B. 5355 kg m^–3
C. 6655 kg m^–3
D. 8130 kg m^–3
Answer : C

Question. A slide with an image 4 cm × 2 cm is placed at a distance of 10 cm behind a converging lens and a clear image is formed on a screen 1.1 m from the slide. The size of the image on the screen is
A. 40 cm × 20 cm
B. 36 cm × 18 cm
C. 20 cm × 40 cm
D. 10 cm × 50 cm
Answer : A

Question. A mass of M kg is suspended by a weightless string of length l. A horizontal force is applied to displace it slowly until the string makes an angle of 30º with the initial vertical direction. What is the work done by the applied force?

A. Mgl (1− √3/2)
B. Mgl (1 - 1/2)
C. Mg l√3/2
D. Mgl/4
Answer : A

Question. Read the given statements and select the correct option.
Statement 1 : Thermonuclear bombs can be more devastating than the atomic bombs.
Statement 2 : Process of nuclear fusion is involved in atomic bomb.
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. Statement 1 is false but statement 2 is true.
Answer : C

Question. Two students X and Y perform experiments on series and parallel combination of two given resistors R₁ and R₂ and plot the graphs as shown here. Which of the following options is true about the graphs obtained by the students?
(V is potential difference and I is current) Graph by student X Graph by student Y

     Series        ​Parallel
A. I, III             II, IV
B. I, IV             II, III
C. II, III             I, IV
D. II, IV             I, III
Answer : B

Question. A car accelerates from rest at a constant rate a for some time after which it decelerates at a constant rate b and comes to rest. If total time elapsed is t, then the maximum displacement of the car will be
A. α+β/αβt²
B. (α² − β²)t²/αβ
C. αβt²/2(α+β)
D. (α+β)t²/ab
Answer : C

Question. A uniform magnetic field exists in the plane of paper pointing from left to right as shown in figure. In the field, an electron and a proton move as shown. 
The electron and the proton experience

A. Forces both pointing into the plane of paper
B. Forces both pointing out of the plane of paper
C. Forces pointing into the plane of paper and out of the plane of paper respectively
D. Forces pointing opposite and along the direction of the uniform magnetic field respectively.
Answer : A

Question. A prism ABC (with BC as base) is placed in different orientations. A narrow beam of white light is incident on the prism as shown in figure. In which of the following cases, after dispersion, the third colour from the top corresponds to the colour of the sky?

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

Question. There are two walls X and Y which are 120 m apart from each other. A boy standing 40 m away from wall X claps his hands once. If the speed of sound in air is 330 m s–1, then what is the time interval between the first and the second echo that he hears?
A. 0.05 s
B. 0.24 s
C. 1 s
D. 2 s
Answer : B

Question. A ray of light enters a water filled glass tank from a glass face making a nonzero angle (< 90°) to the normal. The emergent ray from the opposite face will follow the path which is
A. Deviated to the right from incident ray
B. Deviated to the left from incident ray
C. Same as incident ray
D. Parallel but not along the incident ray.
Answer : D

Question. Fill in the blanks in the given table by choosing an appropriate option.

     (i)          (ii)      (iii)       (iv)          (v)            (vi)
A. 7        CuCl₂   > 7     NH₃          CO₂             7
B. > 7    CuCl₂    < 7     H₂CO₃      NH₄OH     > 7
C. < 7    CuO      > 7     NH₄OH    H₂CO₃         7
D. > 7    CuCl₂   > 7     NH₃          HCl            > 7
Answer : B

Question. If melting point and boiling point of substance X are –82 °C and –60 °C respectively then, which of the following is correct for the substance X?

Answer : B

Question. Read the given passage and fill in the blanks by choosing an appropriate option.
Bleaching powder is a (i) powder. When exposed to air, it reacts with (ii) of the air to liberate Cl₂ gas. It is (iii) in cold water and milkiness of the solution is due to the presence of unreacted (iv) . It reacts with HCl and H₂SO₄ liberating (v) gas.
             (i)                     (ii)              ​​​​​​​     (iii)              (iv)        (v)
A. Blue crystalline     Moisture         Soluble          CO₂       SO₂
B. Yellowish white     CO₂                  Soluble           Lime      Cl₂
C. White                    O₂                     Insoluble        Lime      Cl₂
D. Yellow                  Moisture         Soluble          CO₂       Cl₂
Answer : B

Question. The ratio of the number of molecules in 4 g of hydrogen to the number of molecules in 5.6 dm³ of oxygen at standard temperature and pressure is
[Given: Atomic mass of H = 1 u and O = 16 u]
A. 2 : 1
B. 3 : 4
C. 1 : 4
D. 8 : 1
Answer : D

Question. Rohan added different substances P, Q and R to three beakers each containing 30 mL of water as shown in the figure.

He observed that the temperature of beakers I and II increases while that of beaker III decreases. Substances P, Q and R could be respectively
A. NH₄NO₃, KOH and Na₂CO₃. H₂O
B. NH₄Cl , CuSO₄ and NaCl
C. Na₂SO₄, CaO, CuSO₄. 5H₂O
D. NaNO₃, KCl and K₂SO₄.
Answer : C

Question. The boiling points of some gases are given in the table.

If their liquid mixture is subjected to fractional distillation, the order in which gases will distil over is
A. Kr, O, N, Ne
B. O, N, Kr, Ne
C. Ne, N, Kr, O
D. Ne, N, O, Kr
Answer : D

Question. Study the given flow chart carefully and identify V, W, X, Y and Z.

Answer : B

Question. Kunal, a class 10 student studied the reaction between marble chips and dilute HCl. He took 50 g of marble chips and 100 mL of 0.1 molar HCl solution. The given graph shows how the total mass of marble chips varies with time as the reaction proceeds.

Which of the following statements are incorrect?
I. More and more CO₂ gas is evolved along PQ.
II. CaCO₃ remains unreacted after point P.
III. Reaction gets completed at point P.
IV. Dilute HCl remains unreacted after point P.
A. I and IV only
B. II and III only
C. I, II and IV only
D. II, III and IV only
Answer : A

Question. A part of the periodic table is represented as

In the given section of the periodic table, the most metallic element, the most non-metallic element, the smallest atom and the atom which has complete octet in M shell are respectively
A. Q, R, R and T
B. R, P, P and S
C. Q, R, P and T
D. P, R, S and T.
Answer : A

Question. Atomic structures of elements P and Q are schematically represented as : 

Which of the following statements is / are correct?
I. P and Q will form the compound P₂Q₃.
II. P will form phosphide with formula PP₃.
III. Q exists as a divalent cation.
IV. P can form P5– anion to attain the noble gas configuration.
A. I and II only
B. I and III only
C. III and IV only
D. I only
Answer : D

Question. Consider the following reactions :
I. Ethanol is oxidised by acidified K₂Cr₂O₇.
II. Methane undergoes complete combustion.
III. Ethanoic acid reacts with anhyd.Na₂CO₃.
IV. Ethanol reacts with sodium metal.
Reaction(s) in which water is one of the products is/are
A. I and II only
B. I, II and III only
C. III and IV only
D. II only.
Answer : B

Question. The percentage by mass of water of crystallisation in hydrated copper sulphate is
[Given: Atomic mass of Cu = 63.5 u, H = 1 u, O = 16 u and S = 32 u]
A. 42%
B. 36%
C. 63%
D. 24%
Answer : B

Question. Refer to the given dichotomous key. Identify K, L, M, N, O and P and select the incorrect statement regarding them.
I. (a) The cells of tissue have wall. – Go to II
(b) The cells of tissue lack wall. – Go to V
II. (a) Tissue is made up of similar or only one type of cells. – Go to III
(b) Tissue is made up of more than one type of cells. – Go to IV
III. (a) Wall thickening in tissue cells is uniform. – K
(b) Wall thickening in tissue cells is not uniform. – L
IV. (a) Conducting elements are of two types. – M
(b) Conducting element is of one type. – N
V. (a) It helps in gamete formation. – O
(b) It helps in absorption of water from digested food. – P
A. O could be cuboidal epithelium while P could be columnar epithelium.
B. In M conduction occurs only in one direction, i.e., upward while in N, conduction occurs in both directions, i.e., upward and downward.
C. L provides mechanical support and flexibility to the plant body.
D. K could be parenchyma that occurs chiefly in leaf stalks, leaf midribs and herbaceous dicotyledonous stems but is usually absent in monocots.
Answer : D

Question. Refer to the given pedigree showing a case study of an autosomal dominant disease.

The genetic make-up of the first generation (female and male respectively) is
A. AA, aa
B. AA, Aa
C. Aa, AA
D. Aa, Aa.
Answer : A

Question. In a study, water samples of Ganga river were collected from four different cities (P, Q, R and S) to check the presence of Coliform bacteria. The result obtained was plotted in the given graph.

Select the correct option regarding this.
A. People living in city Q are more prone to waterborne diseases like typhoid, cholera, etc.
B. The river water of city P is most suitable for agriculture.
C. The biological oxygen demand in river of city R is more than that found in city S.
D. Dissolved oxygen content of river Q will be more than that of river R.
Answer : A

Question. Study the given experimental setup.

By measuring the movement of oil drop in the apparatus, what can be investigated?
A. Carbon dioxide released during germination
B. Heat released during germination
C. Oxygen used during germination
D. Water produced during germination
Answer : C

Question. Refer to the given figure of a bryophyte.
Identify the labelled parts P, Q, R and S and select the option which represents the correct number of chromosome in these parts.
Note : [For the given plant, 2n = 24]

      P    Q    R      S
A. 12   24   12    24
B. 24   24   12    12
C. 24   24     8      8
D.  8    24   24    12
Answer : B

Question. Refer to the given figure.

Identify labelled parts P-S and select the correct option regarding them.
A. When nerve impulse reaches presynaptic knob, R releases a chemical called neurotransmitter.
B. P contains Nissl's granules and neurofibrils and conducts impulses away from the cell body.
C. Q is a narrow fluid filled space that lies between presynaptic and postsynaptic knobs formed by dendrite terminal of both neurons.
D. S are chemoreceptors present on axon terminal of postsynaptic membrane.
Answer : A

Question. Refer to the given flow chart and the following list of diseases.

Now, select the option that correctly categorises these diseases into P, Q, R and S.
              P                     Q                      R                  S
A. (vi), (vii), (ix)      (i), (iv)          (ii), (viii), (x)      (iii), (v)
B. (vi), (vii), (ix)      (i), (iv), (x)    (ii), (viii)            (iii), (v)
C. (vi), (vii)             (i), (iv), (ix)   (ii), (viii), (x)      (iii), (v)
D. (i), (vi), (vii)       (iv), (ix)         (ii), (v), (x)        (iii), (viii)
Answer : A

Question. Ruby crossed a tall pea plant with white flowers and a dwarf pea plant with violet flowers. She performed a __________ .
A. Test cross
B. Dihybrid cross
C. Natural selection
D. Monohybrid cross
Answer : B

Question. Refer to the given graph showing different types of white blood corpuscles in a normal man.
Identify P, Q, R and S and select the incorrect statement regarding them.

A. P produces antibodies to destroy microbes and their toxins , rejects grafts and kills tumour cells.
B. Q could be phagocytic in nature and is able to engulf bacteria and cellular debris.
C. Nucleus of R is many lobed whereas nucleus of S is usually two lobed.
D. Cytoplasm of P does not contain granules whereas that of R contains granules.
Answer : C

Question. Read the given paragraph where few words have been italicised.
Cytokinins are the natural substances which enhance growth of stem but in same concentration are incapable of causing growth of intact root. Naphthalene acetic acid is natural whereas indole-3 acetic acid is synthetic auxin. Gibberellins inhibit growth and cause bolting in rosette plants. Abscisic acid stimulates growth and causes abscission of flowers and fruits. Ethylene induces ripening of climacteric fruits and formation of root hair.
Select the correct option regarding it.
A. Cytokinins should be replaced with ethylene.
B. Cytokinins should be replaced with auxins whereas napthalene acetic acid and indole-3 acetic acid should be interchanged.
C. Inhibit and stimulates should not be interchanged as they are correctly mentioned.
D. Ethylene should be replaced with cytokinin.
Answer : B

Question. Refer to the given figure. Identify P - T and select the correct statements regarding them.

(i) Gland P secretes a hormone which plays role in the development of immune system of body.
(ii) Gland Q transmits messages in the form of electrical impulses.
(iii) Hormone released by gland S, enhances blood pressure by stimulating contraction of smooth muscles of arterioles.
(iv) Hypersecretion of a hormone by gland R causes myxedema whereas its hyposecretion causes Graves’ disease.
(v) Hormones secreted by gland T regulate the calcium and phosphate levels in blood.
A. (i) and (iv) only
B. (iii) and (v) only
C. (i), (ii) and (v) only
D. (iii), (iv) and (v) only
Answer : B

ACHIEVERS SECTION

Question. The variation of induced emf (e) with time (t) in a coil if a short bar magnet is moved along its axis with a constant velocity is best represented as

Answer : B

Direction (Q. No.a and b) : Read the given passage and answer the following questions.
When an alcohol is heated with excess of conc. H2SO4 at about 170 °C, it gets dehydrated to form alkene(s). In this reaction, conc. H2SO4 acts as a dehydrating agent.

Question a. Which of the following statements is/are correct when 2-butanol undergoes dehydration?
I. Only one alkene having same number of carbon atoms as in 2-butanol is formed.
II. Two alkenes having different structural formulae but same molecular formula are formed.
III. Only one alkene having one carbon atom less than 2- butanol is formed.
IV. Two alkenes are formed out of which one is terminal and other is non-terminal.
V. Two alkenes having the same percentage composition by mass are formed.
A. II, IV and V only
B. III only
C. II and IV only
D. I only
Answer : A

Question b. If boiling point of an alkene formed in a dehydration reaction of an alcohol is –6°C then, which of the following could be the boiling points of succeeding and preceding members of this alkene in its homologous series respectively?
A. –48 °C and –104 °C
B. 30 °C and 64 °C
C. –104 °C and –48 °C
D. 30 °C and –48 °C
Answer : D

Question. Refer to the given graph showing levels of different hormones (P-S) during menstrual cycle in a normal woman.

Identify the hormones P-S and select the incorrect statement regarding them.
A. R stimulates the ovarian follicles to produce estrogen during proliferative phase while Q stimulates the corpus luteum of the ovary to secrete progesterone.
B. Menstrual phase is caused by the reduction of P and S.
C. Proliferative phase is characterised by increased production of S whereas secretory phase is characterised by increased production of P.
D. In males, Q causes spermatogenesis whereas R stimulates Leydig’s cells to secrete testosterone.
Answer : A

Question. Read the given statements each with one or two blanks. Select the option that correctly fills the blanks in any two statements.
(a) (i) is the process of aerobic burning whereas (ii) is anaerobic burning of combustible constituent of solid waste at high temperature.
(b) (i) secretes mucus and watery alkaline fluid that contains fructose.
(c) Tendrils of Cucurbita and thorns of Bougainvillea are (i) organs while wings of birds and insects are (ii) organs.
(d) Rate of heart beat and breathing movements of human body are controlled by (i) .
A. (b) - (i) - Seminal vesicles;
(c) - (i) - Analogous, (ii) - Homologous
B. (c) - (i) - Homologous, (ii) - Analogous;
(d) - (i) - Medulla oblongata
C. (a) - (i) - Pyrolysis, (ii) - Incineration;
(b) - (i) - Cowper's gland
D. (a) - (i) - Incineration, (ii) Pyrolysis;
(d) - (i) - Diencephalon
Answer : B