# UPSC NCERT GENERAL SCIENCE NOTES: TOPIC WISE SOLVED MCQ’s

## UPSC General Science: Technology-2

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#### Today’s Topic : Technology-2

1. The cloud fleet in the atmosphere because of their low:

a) Temperature and pressure                 b) Pressure and density

c) Only temperature                                 d) None of these.

Ans:     C

Explanation:    When air rises, it is cooled by expansion. After low point has reached cooling lead to condensation of water vapour in the atmosphere. Tiny droplets of water vapour which are too small to fall as rain shower, will be suspended in the air and fleet as clouds.

2.  Consider the following natural phenomena:

1) Diffraction of light                          2) Scattering of light

3) Refraction of light                          4) Terrestrial of light.

Due to which of these phenomena is mirage formed?

a) 1 and 3                 b) 3 and 4                 c) 1 and 4                    d) None of these.

Ans      B

Explanation:    Due to refraction of light and terrestrial of light the mirage forms in deserts. Due to total internal reflection of light which is causes of continuous refraction of rays in a different layer of air, the observer thinks of water where it does not exist.

3. A hunter aims his gun at point between the eyebrow of a monkey sitting on a branch of a long tree. Just a hunter fires, the monkey jumped down. The bullet will:

a) Miss the monkey altogether.                                 b) Hit the monkey at the point aimed.

c) Hit the monkey above the point aimed.                 d) None of these.

Ans     B

Explanation:    The bullet will hit the monkey at the point aimed because the bullet will cover the same vertical distances as of monkey covered the distance.

4. In an atom, the order of filling up the orbital’s is governed by:

a) Aufbau’s principle                      b) Heisenberg uncertainly principle

c) Hund’s rule                                 d) Pauli exclusion principle

Ans:     A

Explanation:    The order of filling up of the orbital is given by Aufbau’s principle which conveys that electron are added to an atom one at a time, starting with lower energy orbital until all the electron have been placed in an appropriates orbital. According to Pauli’s exclusion principle, no two electrons in an atom can have the same value for all the four quantum number, hence there can be maximum of two electrons in an orbital.

5. Which one of the following can be used to conform whether drinking water contains gamma emitting isotopes or not:

c) Spectrophotometer                   d) Scintillation counter

Ans:     D

Explanation:    Scintillation counter is a device used to detect radioactive isotopes. Generally, Alpha, Gamma and Beta rays emitted from radioactive substance emit radiation on the scintillation counter.

6. The Alpha particle carries two positive charges. Its mass is very nearly equal to that of:

a) Sum of masses of two positron and two neutron.

b) Two positrons as each positrons carries a single positive charge.

c) Two protons.

d) An atom of helium.

Ans:     D

Explanation:    Each Alpha particles contains two protons and two neutrons, so its mass is equal to an atom of helium. The molecular weight of the helium atom is same as alpha particle.

7. In addition to protein and carbohydrates other nutritional substances found in milk may be:

1) Potassium (K)                      2) Cobalt (CO)                         3) Iron (fe)                   4) Calcium (Ca)

a) 1,2 and 3                 b) 1,2 and 4                 c) 1,3 and 4                 d) 2,3 and 4

Ans:     C

Explanation:    Milk contains protein, carbohydrates, sugar, fats, sodium, potassium, calcium, iron, vitamins A, B12, C and D, magnesium, phosphorus, thiamine, niacin and riboflavin.

8. Which one of the following elements is alloyed with iron to produce steel which can resist high temperature and also have high hardness and abrasion resistance:

a) Aluminium                 b) Tungstun                   c) Chromium               d) Nickel

Ans:     C

Explanation:    Chromium generally mixed with iron to produced steel, which can resist high temperature and also have high hardness and abrasion resistance. Hardness of steel depends on percentage of chromium.

9. Who among the following is considered as the inventor of the World Wide Web (www) :

a) Vinod Dham                 b) Edward Kasner                 c) Tim Berners –Lee                d) None of these.

Ans:     C

Explanation:    The World Wide Web is a system of interlinked hypertext documents access via the internet, with the web browser, a user views web pages that may contain text image and other multimedia and navigates between them using hyperlinks. It was created around 1990 by the English man Tim-Bernres-Lee and the Belgian Roberts Calling working at CERN in Geneva, Switzerland.

10. India has recently landed its Moon Impact Probe on the moon. Among the following countries, which on landed such probe on the Moon earlier:

1) USA                        2) Russia                      3) Japan                       4) Denmark

a) Only a                 b) All a, b, c, d                 c) a, b and c                 d) None of these.

Ans:    C

Explanation:    In 2008, 14th November India has landed its Moon Impact Probe on the moon. USA, USSR (Russia) and Japan are three countries to have landed previously Moon Impact Probe on the moon. So, the correct answer is (c) .