Electricity: Electric Power

These numerical problems are based on the chapter Electricity class 10 science of NCERT books and CBSE syllabus.

Numerical Problems

Example 1: If the potential difference is 220V and the power of bulb is 110W, what is the electric current flowing in the circuit?

Solution: Given, Potential difference, V = 220V, Power of bulb , P = 110 W

Electric current (I) =?

We know that `P = VI`

Or, `110 W = 220 V xx I`

Or, `I = 110 W ÷ 220 V = 0.5 A`

Example 2: If the power of an electric heater is 1000W and electricity of 240 V is flowing through it, find the electric current in the electric heater.

Solution: Given, Power (P) = 1000W, Potential difference (V) = 240V, Electric current (I) =?

We know that `P = VI`

Or, `1000 W = 240 V xx I`

Or, `I = 1000 W ÷ 240 V = 4.16 A`

Example 3: What is the electric current through an electric geyser of 500W, if the potential difference across the electric circuit is 250V?

Solution: Given, P = 500 W, V = 250 V, therefore, Electric current (I) =?

We know that `P = VI`

Or, `500 W = 250 V xx I`

Or, `I = 500 W ÷ 250 V = 2 A`

Example 4: If the electric current is 10 A and potential different between two terminals is 240V, find the power of the electric appliance.

Solution: Given, Electric current (I) = 10 A, Potential difference (V) = 240 V, Power (P) =?

Since, `P = V xx I`

Therefore, `P = 240 V xx 10 A = 2400 W`

Example 5: Find the power of electric iron, if electric current through the circuit is 5 A and potential difference is 220V.

Solution: Given, Electric current (I) = 5 A, Potential difference (V) = 220 V, Power(P) =?

We know that, `P = V xx I`

Or, `P = 220 V xx 5 A = 1100 W`