PHYSICS [2 Mark Question Answer]

The sun is called the ultimate source of energy because it is the source of almost all energies of the earth. Plants convert light energy from the sun into chemical energy (food) by the process of photosynthesis.

(a) The energy released when we burn wood, coal, oil or gas is called heat energy. Steam possesses the heat energy which is capable of doing work. Therefore we can say that heat is a form of energy which is capable of doing work
(b) The water in the pressure cooker is converted into steam by the heat energy in the burning flame under the pressure cooker. The water and the steam get energy from the heat. This energy works by displacing the nozzle. So, we can say heat is a form of energy.

(a) Kinetic energy is the energy an object has because of its motion. If we want to accelerate an object, then we must apply a force. Applying a force requires us to do work. After work has been done, energy has been transferred to the object, and the object will be moving with a new constant speed
(b) A river flowing at a certain speed comprises kinetic energy as water has a certain velocity and mass.

(a) Potential energy refers to the energy which an object holds due to its position relative to other objects, stresses within itself, its electric charge, or other factors.
(b) For example- Potential energy possessed by water is used to harness electrical energy. Water raised to a certain height gains potential energy with respect to the ground due to the gravitational force acting on it.