Exercise 3

Question 6 :

Mach number is used in connection with the speed of


A). sound
B). aircraft
C). spacecraft
D). ships
Answer : Option B

Question 7 :

On a stationary sail boat, air is blown from a fan attached to the boat. The boat


A). moves in opposite direction in which the air is blown
B). does not move
C). moves in the same direction in which air blows
D). spins around
Answer : Option B

Question 8 :

Rainbow is due to


A). absorption of sunlight in minute water droplets
B). diffusion of sunlight through water droplets
C). ionisation of water deposits
D). refraction and reflection of sunlight by water droplets
Answer : Option D

Question 9 :

Stars which appear single to the naked eye but are double when seen through a telescope are


A). novas and supernovas
B). binaries
C). asteroids
D). quasars
Answer : Option B

Question 10 :

ML2T-2 is the dimensional formula for


A). moment of inertia
B). pressure
C). elasticity
D). couple acting on a body
Answer : Option D