Basics Of Energy And Its Various Forms - Practice Questions & MCQ

• Energy-

1.  The energy of a body is defined as its capacity for doing work.
   2. It is a scalar quantity
   3. Dimension- $M{L}^2{T}^{-2}$
   4. Unit-

   $$\begin{array}{rl}& \text{ SI unit - Joule }\\ & \text{ CGS - Erg }\\ & \text{ and, }1\text{ Joule }={10}^7\mathrm{Erg}\end{array}$$

   5. Mass energy equivalence-

   Einstein's special theory of relativity shows that material particle itself is a form of energy.
   The relation between the mass of a particle $m$ and its equivalent energy is given as

   $$E=m{c}^2$$

   
   Where $\mathrm{c}=$ velocity of light in vacuum.
   E.g - If $\mathrm{m}=1\mathrm{kg}$ then $E=9\ast {10}^{16}\mathrm{J}$

6. Various forms of energy 

•  Mechanical energy (Kinetic and Potential)

• Chemical energy

• Electrical energy

•  Sound energy

• Heat energy

• Light energy

7. Transformation of energy-

Conversion of energy from one form to another is possible through various devices and processes.

Examples are - 

• Bulb- Electrical energy gets converted into light energy.

• Speaker-Electrical energy gets converted into sound energy.

• Heater- Electrical energy gets converted into heat energy