Physics 2002 JAMB Past Questions - Question 31: An electric iron is rated 1000W, 230V. What is the resistance of its element?

Correct Answer

C

Explanation

P=v2/R =1000 =(230)2/R;R =52.9 ohmsTo find the resistance of the heating element in the electric iron, you can use Ohm's law, which relates voltage (V), current (I), and resistance (R):

Ohm's Law: V = I * R

Where:
- V is the voltage (230V in this case).
- I is the current.
- R is the resistance (what we want to find).

You already have the voltage (V) and you know that the power (P) of the iron is 1000W (watts). You can use the formula for power:

Power (P) = V^2 / R

You can rearrange this formula to solve for resistance (R):

R = V^2 / P

Substitute the values:

R = (230V)^2 / 1000W

R = 52900V^2 / 1000W

R = 52.9 ohms

So, the resistance of the heating element in the electric iron is approximately 52.9 ohms.