Unit - 1.1 Area And its Measurement — PHYSICS STD 7 — Question

During a thunderstorm, the sound of a thunder is heard after the lightning is seen. Why ?

Define the following :Solidification point

Given below statement is incorrect. Write the correct statement :
The energy released during splitting of nucleus of an atom is in the form of light energy.

State and define SI unit of weight.

State the types of motion of the carpenter’s saw?

Define the following when reflection takes place from the surface of a plane mirror :angle of incidence

Given below statement is incorrect. Write the correct statement :
When the sound travels in air, the particles of air vibrate differently compared to the vibrations of the vibrating body.

By giving four example each, define:Non-flammable substances

You recognize your friend by hearing his voice on a telephone. Explain.

Define the following when reflection takes place from the surface of a plane mirror : reflected ray