Question

How much current will an electric heater draw from a $ 220V $ , if the resistance of the heater is $ 40 $ ohms?

Answer 1

Hint :In order to find the answer to the above question, we have to use the Ohm’s law expression,
 $ V \propto I $
Where, V is Voltage, I is current.

Complete Step By Step Answer:
As asked in the question about the current drawn from a voltage by supply by a heater of resistance $ 40 $ ohms, we have to remove the proportionality sign by the constant R, hence the above equation will become,
 $ V = I \times R $
 Where, V is Voltage in Volts.
I is current in ampere.
R is resistance in ohms.
As Voltage is given in question as $ 220V $ and also the resistance of the heater is provided as 40 ohms, so after substituting these values in above equation we will get,
 $ 220 = I \times 40 $
Now, rearranging the above equation will give us,
 $ I = \dfrac{{220}}{{40}} $
 $ I = 5.5{\text{ A}} $
So, the current drawn by the electric heater is found to be $ 5.5 $ Ampere.

Additional Information:
Voltage is the work to be done, upon a unit charge to move between two points, against a static electric field. A voltage which is a measure of electric potential difference is the cause of electrical current to flow in a closed circuit.

Note :
The unit of Voltage and Resistance should be kept or taken in Volts and ohms respectively in order to get the current in ampere. There should not be any confusion about potential and voltage. These are two slightly different terminologies, Voltage is not exactly potential but it is the measure of the electric potential difference between two points.