General Knowledge (Part-B: English) NDA/NA SOLVED PAPER 2021-II (101 to 150)

Total Questions: 50

21. An object of mass 2000 g possesses 100 J kinetic energy.

The object must be moving with a speed of

Correct Answer: (a) 10.0 m/s
Solution:

22. Which one of the following ions is not iso-electronic with F⁻ ?

Correct Answer: (d) N⁻
Solution:Iso electronic species have same number of electrons Total number of electrons in F⁻ is 9 whereas total number of electrons in N⁻ is 8.

23. What is the total number of covalent bonds in methanol?

Correct Answer: (c) 5
Solution:Methanol is CH3OH
So carbon is attached to 3 H and 1 OH with 4 covalent bonds. O and H in OH is bonded with 1 covalent bond. So there are a total of 5 covalent bonds.

24. Which one of the following is the chemical formula of Plaster of Paris?

Correct Answer: (a) CaSO₄. H₂O
Solution:CaSO₄. 1/2 H₂О.
Calcium sulphate with half a molecule of water per molecule of salt (hemihydrate) is called plaster of Paris. It is prepared by heating gypsum (CaSO₄. 2H₂O ) at 120°C in rotary kilns, where it gets partially Gehydrated.

25. The unit of the ratio between thrust and impulse is same as that of

Correct Answer: (a) frequency
Solution:

26. Which one of the following figures correctly shows the path of a ray of light through a glass prism?

Correct Answer: (a)
Solution:

27. When a light beam falls on a triangular glass prism, a band of colours is obtained. Which one of the following statements is correct in this regard?

Correct Answer: (c) Violet light bends the most, as the refractive index of glass for violet light is greatest.
Solution:Violet light will deviate the most and it is because of the refraction of light
The phenomenon of splitting white light into its seven constituent colours when it passes through a glass prism is called dispersion of white light. The various colours seen are Violet, Indigo, Blue, Green, Yellow, Orange and Red Dispersion by prism
The figure shows the dispersion of lightwave by a prism. When a white light incident on a glass prism, the emergent light is seen to be consisting of several colours (violet, indigo, blue, green, yellow, orange and red). The red light bends the least, while the violet light bends the most (as shown in the figure above).

28. The image of an object formed by a plane mirror is

Correct Answer: (b) erect, virtual and same size.
Solution:The images formed from plane mirrors are the reflected images in their normal proportions but reversed from left to right. These are the most widely used mirrors. Characteristics of the image formed in a plane mirror are:
  • It is virtual
  • It is erect and of the same size as the object
  • The image is laterally inverted.
  • The size of the image is the same as the size of the object.
  • The distance of the object from the plane mirror is the 13 same as the distance of the image from the plane mirror.

29. Which one of the following is not a conservative force?

Correct Answer: (a) Frictional force
Solution:A conservative force is a force done in moving a particle from one point to another, such that the force is independent of the path taken by the particle.
Gravitational force is an example of a conservative force, while frictional force is an example of a non-conservative force. Other examples of conservative forces are a force in elastic spring, the electrostatic force between two electric charges, and magnetic force between two magnetic poles.

30. A negative work is done when an applied force Fand the corresponding displacement S are

Correct Answer: (c) anti-parallel to each other.
Solution:(c)