Sound — PHYSICS STD 7 — Question

The appropriate unit to express the area of a two rupees coin is___________ .

The phenomenon due to which the left side of an object, appears as the right side of image during reflection of light is called ___________ .

A U-shaped fork of steel used as a convenient source of sound in laboratory is called ___________ .

Black objects are good ___________ of heat.

All bodies which emit light energy by themselves are called ___________ bodies.

The speed of sound in ___________ is around 332 ms^-1.

Mercury is the only liquid which gets heated up due to the process of ___________ .

When a solid directly changes to gaseous state on heating, without changing to the liquid state, the gaseous material so formed is called ___________ .

Total distance travelled = _______ × total time taken.

The SI scale of temperature is called ___________ scale.