If the current I through a resistor is increased by 100%

• GP Electricity

If the current I through a resistor is increased by 100% (assume that temperature remains unchanged), the increase in power dissipated will be

1. 100%
2. 200%
3. 300%
4. 400%

Answer

If I is current and R is resistance then,

Power, P = I²R

Power in first case, P₁ = I²R

100% increase in current means that current becomes 2I

Power in second case, P₂ = (2I)²R = 4I²R

Now, increase in dissipated power = P₂ – P₁ = 4I²R – I²R = 3I²R

Percentage increase in dissipated power = 3P₁/P₁ × 100 = 300% 

The correct option is C.