NDA/NA SOLVED PAPER 2015-II (GENERAL KNOWLEDGE)

Total Questions: 100

41. Which of the following are the properties of an electron?

1. Electron is a constituent of cathode ray
2. Electron is a negatively charged particle
3. The mass of the electron is equal to the mass of the proton
4. Electron is deflected by the electric field but not by magnetic field

Select the correct answer using the code given below:

Correct Answer: (a) 1 and 2 only
Solution:

Cathode rays are composed of negatively charged particle electron.

42. Carbon and energy requirements of autotrophic organisms are fulfilled by:

Correct Answer: (a) Photosynthesis
Solution:

Photosynthesis is a process in which carbon is taken from the atmosphere is taken in form of carbon di oxide. Energy is also synthesized in light reaction is subsequent steps.

43. The resistance of a wire of length / and area of cross-section a is x ohm. If the wire is stretched to double its length, its resistance would become:

Correct Answer: (c) 4 x ohm
Solution:

Resistance is directly proportional to length(l)
r∝l, r∝l/a
wire is stretched to double its length the resistance will become
r∝l, r∝l/a/2 Combining these two r∝4l/a

44. Which one of the following describes the Lithosphere?

Correct Answer: (b) Crust and upper mantle
Solution:

Lithosphere consists of crust and upper mantle.

45. Which of the following statements regarding heavy water are correct?

1. It is extensively used as a moderator in nuclear reactors
2. It cannot be used in exchange reaction to study reaction mechanism
3. Viscosity of heavy water is relatively smaller than that of ordinary water
4. The dielectric constant of heavy water is smaller than that of ordinary water

Select the correct answer using the code given below:

Correct Answer: (d) 1 and 4
Solution:

Most commercial nuclear reactors use normal water (also called light water) as a neutron moderator. Dielectric constant of heavy water is smaller than that of ordinary water.

46. Conservation of momentum in a collision between particles can be understood on the basis of:

Correct Answer: (c) Both Newton's second law of motion and Newton's third law of motion
Solution:

Conservation of momentum in a collision between particles is dependent on both Newton's second law of motion and Newton's third law of motion.

47. Which one of the following statements is not correct?

Correct Answer: (b) Temperatures in equatorial regions change substantially from January to July
Solution:

The temperature in equatorial regions does not change substantially from January to July. They experience very little temperature variation throughout the year due to the consistent angle at which the sun's rays hit the equator, resulting in minimal seasonal change. Thus, option (b) is incorrect.

48. To weld metals together, high temperature is required. Such a high temperature is obtained by burning:

Correct Answer: (a) Acetylene in oxygen
Solution:

Oxy-fuel welding (commonly called oxyacetylene welding, oxy welding, or gas welding) and oxy-fuel cutting are processes that use fuel gases and oxygen to weld and cut metals.

49. Two forces, one of 3 newton and another of 4 newton are applied on a standard 1 kg body, placed on a horizontal and frictionless surface, simultaneously along the x-axis and the y-axis, respectively, as shown below:


The magnitude of the resultant acceleration is :

Correct Answer: (c) 5m/s²
Solution:

Final force will be along the Z axis.
F=√(3)²+(4)²
=√9+16=√25=5
Acceleration(a)= F/m=5/1= 5m/s²

50. Magnetic meridian is an imaginary:

Correct Answer: (c) vertical plane