Question

The voltage drop across a 2 kilo-watt electric heater element, whose resistance when hot is 20 ohms, is:
1. 200 V
2. 20 V
3. 100 V
4. 220 V

Answer 1

Correct Answer - Option 1 : 200 V

CONCEPT:

• Electric Power: The rate at which electrical energy is dissipated into other forms of energy is called electrical power i.e.,

\(P = \frac{W}{t} = VI = {I^2}R = \frac{{{V^2}}}{R}\)

Where V = Potential difference, R = Resistance and I = current.

CALCULATION:

Given - Power (P) = 2 kW = 2000 W and R = 20 Ω

• The voltage drop across a 2 kilo-watt electric heating element is 

⇒ V² = P × R = 2000 × 20 = 40000 V

⇒ V = 200 V