Waves, light, sound

Question 1 of 10

A converging lens of focal length 20 cm forms a real image 60 cm from it. The object distance is

Question 2 of 10

An object 15 cm from a concave mirror of focal length 10 cm forms an image at

Question 3 of 10

The bending of waves around obstacles is called

Question 4 of 10

Which of the following is a longitudinal wave?

Question 5 of 10

Which electromagnetic waves have the longest wavelength?

Question 6 of 10

Light travels from air into glass of refractive index 1.5. Its speed in glass is

Question 7 of 10

An echo is heard 2 s after a shout at a cliff. Speed of sound 340 m/s. The cliff is

Question 8 of 10

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

Question 9 of 10

A string vibrating in its fundamental mode has length 0.5 m. The wavelength is

Question 10 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.