(a) Give a simple example to prove that heat is a form of mechanical energy. (b) Name three devices/industries in which heat energy is put to some useful work.

(a) Give a simple example in nature to prove that light is a form of energy. (b) Give examples to prove (i) light energy changes into chemical energy. (ii) light energy changes into electric energy.

Give one example to show that the sum of potential energy and kinetic energy remains constant if friction is ignored.

Give an example to show that the whole numbers are commutative under: multiplication

Give an example to show that the whole numbers are commutative under: addition

Give and example to show that movement of internal body parts is essential for carrting out Vital processes in organism .

Energy can exist in several forms and may change from one form to another. Give two examples to show the conversion of energy from one form to another.

Give one example to show the conversion of potential energy to kinetic energy when put in use.

Give two examples to show that greater the mass, greater is the inertia of the body.

(a) Give a simple example to prove that sound is kind of energy. (b) Name a device which converts sound dnergy into (a) electric energy (b) magnetic energy.