Question

What will be current drawn by a 1 kW electric heater if its resistance in fully
heated condition is 40 oh

2.5A
40
O 10A
O 1.25A
45​

Answer 1

Given,

Power of electric heater = 1kW = 1000 W

Resistance of the heater = 40 Ω

To Find,

The current drawn by the heater.

Solution,

The formula for calculating the power of an electrical appliance is

P = VI

Also,

P = (RI)I  [ because V = RI ohm,s law ]

P = RI²

where P is the power of the appliance, R is the resistance, and I is the current.

So,

1000 = 40*I²

I² = 25

I = 5 ampere

Hence, the current drawn by the heater is 5 ampere.

Answer 2

Answer:

5 ampere

Explanation:

Formula of  power in a given electrical appliance is

P = VI

substituting the value of v

P = (IR)I  [ because V = IR ohm,s law ]

P = I²R

where P is the power ,

R is the resistance, and

I is the current.

substituting the value of P= 1000W and R = 40 ohm

1000 =I²*40

I² = 25

I = 5 ampere

Hence, the current drawn by the heater is 5 ampere.