General Knowledge (NDA/NA SOLVED PAPER 2023) (51 to 100)

Total Questions: 50

1. The streaming of light beams coming from the Sun through trees is said to have suggested that light travels in straight line. The particles on the path of light beams are visible to us because

Correct Answer: (b) dust particles in the air scatter light into our eyes
Solution:The scattering of light by colloidal particles like dust, smoke, water droplets etc, This phenomenon is known as tyndall effect. It is seen when a fine beam of sunlight enters a dusty room, Thus, the scattering of light makes the particle visible.

2. The flash of lightning is seen before the thunderstorm is heard. It verifies that

Correct Answer: (b) light travels much faster than sound
Solution:Light travels much faster than sound. speed of light c = 3 ×10⁸m / s while speed of sound 343.2 metres per second. Therefore the flash of light seen before the thunderstorm heard.

3. The potential difference between the two end terminals of an electric heater is 220 V and the current through it is 0.5 A. What would be the current through the heater if the potential difference across the terminals of the heater is reduced to 120 V?

Correct Answer: (c) 0. 27A
Solution:

4. The heating element in an electric iron is usually made of

Correct Answer: (c) Nichrome
Solution:The heating element in an electric iron is an alloy consisting of 80% of Nickel and 20% of Chromium. The melting point of Nichrome is 1400 °C with high resistance. due to resistance energy loss convert into heat.

5. Sita, 1.5 m high, stands before a plane mirror fixed on a wall to view her full image. What should be the minimum height of the plane mirror so that Sita can view her image fully?

Correct Answer: (c) 0.75 m
Solution:(c)

6. Galvanization is a method of protecting iron from rusting by coating with a thin layer of

Correct Answer: (c) Zinc
Solution:Galvanisation is applying a coating of zinc metal to prevent corrosion of iron and steel. It makes a stable compound zinc oxide to react with water.

7. Which one of the following alloys contains a non-metal as one of its constituent?

Correct Answer: (d) Steel
Solution:Steel is an alloy that contains a non-metal carbon as one of its constituents. It consists of iron with carbon (0.1 to 1.5%).

8. Buckminster fullerene, which looks like a football, is an allotropic form of

Correct Answer: (c) Carbon
Solution:It is a allotrops of carbon. Buckminster fullerene is a type of fullerene with the formula C60. It has a cage like fused-ring structure made of twenty hexagons and twelve pentagons, and resembles a soccer ball. Each of its 60 carbon atoms is bonded to its three neighbors.

9. Which one of the following graphs correctly represents the current (I) - voltage (V) variation for a rectangular piece of a semiconductor wafer?

Correct Answer: (a)
Solution:(a)

10. The green plants in a terrestrial ecosystem absorbs sunlight that falls on their leaves and convert it into food energy. The percentage of solar radiation absorbed by all green plants for the process of photosynthesis is about

Correct Answer: (a) 1%
Solution:Green plants are autotrophs which trap solar radiation and convert it into food. Plants typically trap 1 percent of the available solar energy in the process of photosynthesis. Photosynthesis is the most important biological process on earth. It makes food and oxygen available to all the heterotrophs.