Part – B General knowledge (English) (NDA/NA SOLVED PAPER 2019 (I) (101 to 150)

Total Questions: 50

1. On exposure to moist air, copper gains a green coat on its surface due to formation of which one of the following compounds?

Correct Answer: (a) Copper carbonate
Solution:

On exposure to moist air, copper gains a green coat on its surface due to formation of copper carbonate.

2. Which one of the following will not produce carbon dioxide on reacting with an aqueous solution of hydrochloric acid?

Correct Answer: (b) Quicklime
Solution:

Calcium carbonate occurs in nature in several form like limestone,chalk, marble, etc. It reacts with aqueous solution of hydrochloric acid (HCl) to liberate carbon dioxide.

3. Which one of the following substances is not a mixture?

Correct Answer: (a) Ice
Solution:

Mixtures are obtained by mixing two or more substances in any proportions. Thus, among the given options, ice is not a mixture as it contains only water (liquid). The other substances, i.e., ice-cream, air and honey are mixtures.

4. Which one of the following is an example of Salt-Crystal growth?

Correct Answer: (b) Physical weathering
Solution:Physical weathering is an example of Salt-Crystal growth. Physical weathering is a term used in science that refers to the geological process of rocks breaking apart without changing their chemical composition. Over time, movements of the earth and environment can break apart rock formation, causing physical weathering.
It can also refers to other things in the environment, breaking down, like soil and mineral, pressure, warm temperature, water and ice can cause physical weathering.

5. Which one of the following is the correct sequence of proved coal reserves in the Indian States in decreasing order?

Correct Answer: (b) Jharkhand, Odisha, Chhattisgarh, West Bengal
Solution:

Coal is the main source of energy in India as it fulfils about 67% of the total commercial energy consumed in the country.
The decreasing order of proved coal reserve is given below

6. Consider the following statements relating to Richter scale:

1. It was devised in 1935 by Charles F Richter.
2. It describes the quantity of energy released by a single earthquake.
3. Richter scale has no upper limit.
Which of the statement(s) given above is/are correct?

Correct Answer: (b) 1 and 2
Solution:

Richter scale is a scale of number used to indicate the magnitude of earthquakes. Charles Francis Richter developed the Richter scale in 1935. This scale describes the quantity of energy released by earthquake. Numbers for the Richter scale range from 0 to 9. So, here statements (1) and (2) are correct.

7. Which one of the following ocean currents is not a cold ocean current?

Correct Answer: (c) Kuroshio current
Solution:

Ocean current is a continuous movement of ocean water from one place to another. It is created by wind, water temperature, salt content and gravitational force of Moon. It is of two types; cold and warm ocean currents. Examples of warm ocean current are Kuroshio, Alaskan, El Nino, East Australian, Florida, Gulf stream, Brazilian and Agulhas ocean currents. Examples of cold ocean current are Humboldt or Peruvian, Kuril or Oyashio, California, Antarctica, Okhotsk, Labrador, Canary and Falkland ocean currents. Hence, option (c) is correct.

8. What is the time gap in occurrence of two successive tides at a given place on the ocean surface?

Correct Answer: (b) 12 hr 26 min
Solution:

A lunar day has a length of 24 hours and 52 minutes. Earth rotates through two tidal ‘bulges’ every lunar day. So, coastal areas experience two high and two low tides in every 24 hours and 52 minutes.
There are two high tides occur in the interval of 12 hours and 26 minutes. Hence option (b) is correct answer.

9. Tooth enamel is made up of which one of the following calcium compounds?

Correct Answer: (d) Calcium phosphate
Solution:

Enamel is the hardest substance in the human body. It contains the highest percentage of minerals, 96% with water and organic material composing the rest. The primary mineral present in enamel is hydroxyapatite which is a crystalline calcium phosphate.

10. Suppose there are two planets, 1 and 2, having the same density, but their radii are R₁ and R₂ respectively, where R₁ > R₂. The accelerations due to gravity on the surface of these planets are related as:

Correct Answer: (a) g₁ > g₂
Solution: