In the diagram given the hanging mass m2 is adjusted until m1 is on the verge of sliding. The coefficient of static

Which of the following may be used to explain a mirage?
I. Layers of air near the road surface have varying refractive indices in hot weather
II. Road surfaces sometimes becomes invisible in hot weather
III. Light from the sky can be refracted upwards after coming close to the road surface.

In the diagram given if the atmospheric pressure is 760mm, the pressure in the chamber G Is

Which of the following has the lowest internal resistance when new?

The pitch of an acoustic device can be increased by