Revision Series | Science | General Science | 38

November 22, 2023

The main precursors of winter smog are

(A) N2O and hydrocarbons
(B) NOx and hydrocarbons
(C) SO2 and hydrocarbons
(D) SO2 and ozone

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Answer- B

In winter the air can become loaded with the products of incomplete combustion such as (PM), (VOCs), (CO), nitrogen oxides (NOx) and hydrocarbons.
The severity of the resulting winter smog depends on the degree of atmospheric dispersion. The lower the level of atmospheric dispersion, the higher the level of winter smog. Hence option B is correct.

Match List I with List II:
List I (Acid) = List II (Source)
(a) Ascorbic acid = (i) Apples and pears
(b) Malic acid = (ii) Ant stings
(c) Formic acid = (iii) Tamarind and grapes
(d) Tartaric acid = (iv) All citrus fruits

(A) a-ii, b-iii, c-iv, d-i
(B) a-iv, b-iii, c-ii, d-i
(C) a-iv, b-i, c-ii, d-iii
(D) a-iv, b-iii, c-i, d-ii

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Answer- C

There are two statements given below:
Statement I : Steam produces less severe burns than water at the same temperature.
Statement II : Dry ice is colder than regular ice. In the light of the above statements, choose the most appropriate answer from the options given below:

(A) Both Statement I and Statement II are correct
(B) Both Statement I and Statement II are incorrect
(C) Statement I is correct and Statement II is incorrect
(D) Statement I is incorrect and Statement II is correct

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Answer- D

Steam will produce more severe burns than boiling water since steam has more warmth vitality than water because of its dormant warmth of vaporization. Even at the same temperature the bubbling (boiling) water produces less severe burns than steam. Hence Statement I is incorrect.
Dry Ice is frozen carbon dioxide. Unlike most solids, it does not melt into a liquid, but instead changes directly into a gas. This process is called sublimation. The temperature of dry ice is around -109° F or -78.5° C while ice has a temperature of 0° C. Hence Dry ice is colder than regular ice and Statement II is correct.
Hence option D is correct.

Arrange the following electromagnetic waves according to the increasing frequency :
(1) Gamma rays
(2) X-rays
(3) Radio waves
(4) Microwaves

(A) (3), (4), (2), (1)
(B) (1), (2), (4), (3)
(C) (2), (1), (4), (3)
(D) (4), (3), (1), (2)

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Answer- A

The correct order of increasing frequency of the electromagnetic spectrum is: Radio waves, micro waves, infrared waves, visible light, ultraviolet radiations, X rays, γ rays (Gamma Rayes). Hence (3), (4), (2), (1) is the correct order and option A is correct

What is the SI unit of amount of Substance?

(A) Mol
(B) Coulomb
(C) Calori
(D) Mole

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Answer- D

Which of the following statements is correct ?

(A) A very small opaque object does not change the straight path of light.
(B) Convex mirrors are generally used in torches.
(C) The mass density of kerosene is less than that of water.
(D) The ability of a medium to reflect light is expressed as optical density.

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Answer- C

Match List I with List II and choose the correct answer from the given options
Action = Related to
A. Peristaltic movement = 1. Saliva
B. Gastric Glands = 2. Alimentary Canal
C. Amylase = 3. Inner lining of Stomach
D. Bile Juice = 4. Liver

(A) A – 4, B – 3, C – 2, D – 1
(B) A – 3, B – 4, C – 1, D – 2
(C) A – 1, B – 2, C – 3, D – 4
(D) A – 2, B – 3, C – 1, D – 4

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Answer- D

Dental alloy for teeth filling contains:

(A) Silver, mercury, tin, copper and zinc
(B) Siler, gold, tin, copper and zinc
(C) Silver, mercury, tin, copper and aluminium
(D) Gold, mercury, tin, copper and zinc

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Answer- A

Which of the following processes does not occur in the water cycle

(A) Condensation
(B) Infiltration
(C) Evaporation
(D) Composition

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Answer- D

Which part of the brain maintains posture and equilibrium of the body?

(A) Fore-brain
(B) Mid-brain
(C) Hind-brain
(D) Spinal cord

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Answer- C