Find the power dissipated in a 20 ohm resistor carrying a current of 3 A — Physics problems | PhysLabo
Loading...

Power of a resistor

Easy 10 grade Electricity / Electric Current
Problem statement

A current of strength $I = 3$ A flows through a resistor of resistance $R = 20$ ohm. Find the power dissipated in the resistor.

Given
  • $R = 20$ ohm
  • $I = 3$ A
  • $P = ?$
Hints
Hint 1 / 2
Power: $P = I^2R$ (the Joule-Lenz law in another form).
Hint 2 / 2
Square the current first.
Solution

Electric power:

$$P = I^2 R = 3^2 \cdot 20 = 9 \cdot 20 = 180 \text{ W}$$

Answer

$P = 180$ W

Problems in this chapter
Back to the chapter list