(True/False): A balloon is filled with hydrogen gas. For sound waves it acts as a convex lens.

A balloon is filled with hydrogen. For sound waves, this balloon behaves like

The propagation of sound waves in a gas involves

A rubber balloon filled with hydrogen gas is left free in air. Then the balloon

The wavelength of sound wave in a gas is -

A balloon is filled with hydrogen at a given pressure at 20^(@)C. What fraction of gas will escape out of the balloon if the temperature rises to 40^(@)C at constant pressure ?

(a) When does a body sink in a fluid? (b) Why does a balloon filled with hydrogen gas rise up against gravity?