Waves, light, sound

Question 1 of 10

A ray of light passes through the optical centre of a lens

Question 2 of 10

The refractive index of a medium is 1.5. If the speed of light in air is 3 × 10⁸ m/s, find the speed of light in the medium.

Question 3 of 10

The apparent depth of a pool 2 m deep (n of water = 4/3) is

Question 4 of 10

The speed of sound in air is about

Question 5 of 10

An echo is heard 2 s after a sound is made in front of a cliff. If the speed of sound is 340 m/s, the cliff is

Question 6 of 10

The pitch of a note depends on its

Question 7 of 10

A wave has a frequency of 50 Hz and a wavelength of 4 m. Find its speed.

Question 8 of 10

Which electromagnetic wave has the longest wavelength?

Question 9 of 10

Beats of frequency 4 Hz are heard when a 256 Hz fork is sounded with another fork. The other fork could be

Question 10 of 10

The loudness of a sound depends on its