set 8 MCQ Questions & Answers Detailed Explanation

Question : 1

Bats can fly during dark nights and also prey. This is because

a) Their night vision is very good

b) Every bird can do this

c) The pupil of their eyes is large

d) They produce ultrasonic waves and are guided by them

Question : 2

The radius of curvatute of the plane mirror is

a) Infinity

b) One

c) Zero

d) Between one and infinity

Question : 3

A noise level of 100 decibel would correspond to

a) Ordinary conversation

b) Sound from a noisy street

c) Just audible sound

d) Noise from a machine shop

Question : 4

A solid is melted (above the melting point) and allowed to cool down at normal condition.Its variation of temperature as a function of times is as shown in the figure given below. What is the reason for the plateau(flat position) in the central region of the cooling curve as shown in the figure?

a) Specific heat of the solid

b) Latent heat of fusion of the solid

c) Thermal conductivity of the solid

d) Thermal capacity of the solid.

Question : 5

Ventilators are provided at the top of room

a) to maintain conventional currents to keep the air fresh in the room

b) to bring oxygen for breathing

c) so that sunlight may enter the room

d) to provide an outlet for carbon dioxide

Question : 6

Consider the following statements:

1. The values of u and f for a concave lens are always negative by convention.
2. The power of a convex lens is negative and that of a concave lens is positive.
3. A concave lens always forms a virtual, erect and smaller image.

a) 2 and 3

b) 1 and 2

c) 1 and 3

d) 1, 2 and 3