Physics Past Questions and Answers

In order to find the depth of the sea, a ship sends out a sound wave and receives an echo after one second. If the velocity of sound in water is 1500ms-1, what is the depth of the sea?

A 0.75km
B 1.50km
C 2.20km
D 3.00km
E 3.75km

Question 352:

When a sound wave passes from air into water its

A Speed and frequency increases but its wavelength remains the same
B Speed and wavelength increases but its frequency remains the same
C Speed decreases
D Speed remains the same but its frequency and wavelength change
E Speed increases but its frequency and wavelength decreases

Question 353:

If the fundamental frequency of a closed pipe organ on a day when the speed of sound is 340ms-1 is 170Hz, then the length of the pipe is

A 50cm
B 70cm
C 100cm
D 150cm
E 200cm

Question 354:

An object is placed 15cm in front of a concave mirror of radius 40cm. The image formed

A Virtual and 60cm behind the mirror
B Real and 60cm behind the mirror
C Virtual and at infinity
D Real and at infinity
E Virtual and 40cm from the mirror

Question 355:

A 45o triangular glass prism can be used as a reflector of light because

A A refraction never takes place in such a prism
B The angle of reflection equals the angle of incidence
C The refractive index of glass is less than 1
D It is transparent
E The critival angle angle for glass is less than 45o