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-

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

   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 $E=9 * 10^{16} \mathrm{~J}$

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