Question

The potential difference between the terminals of an electric heater is 40V when it draws a current of 5 A from the source. What current will the heater draw if the potential difference is increased to 240 V?​

Answer 1

Answer:

30A

$\rule{70mm}{2pt}$

GIVEN: The potential difference between the terminals of an electric heater is 40V when it draws a current of 5 A from the source. Later the potential difference increased to 240 V.

TO FIND: Current that heater will draw if the potential difference is increased to 240 V.

SOLUTION:

We have the value of potential difference i.e. 40 V, current having value 5A.

$\sf{\underline{\underline{\green{\huge{By\:ohm's\:law}}}}}$

According to it, at constant temperature; the current i.e. 'I' flowing through the conductor is directly proportional to the potential difference i.e. 'V'.

→ V ∝ I

→ V/I = constant

→ V/I = R

→ V = IR (ohm's law)

$\underline{\boxed{\huge{\red{\sf{V\:= \:IR}}}}}$

(Where V is potential difference, I is current and R is resistance)

Assumption: Let's say that the resistance is x ohm.

Substitute the values,

$\implies\:\sf{40\:=\:5\:\times\:x}$

Divide by 5 on both sides,

$\implies\:\sf{\dfrac{40}{5}\:=\:\dfrac{5x}{5}}$

$\implies\:\sf{8\:=\:x}$

$\implies\:\sf\boxed {\red{x\:=\:8\:ohm}}$

Therefore, the resistance of an eclectic bulb is 8 ohm when the potential difference between the terminals of an electric heater is 40V and drawn current is 5A.

Now, the potential difference is increased to 240 V and from above resistance is 8 ohm. This time we need to find out the current.

Assumption: Let's say that the current is 'y'.

$\underline{\boxed{\huge{\red{\sf{I\:= \:\dfrac{V}{R}}}}}}$

Substitute the values,

$\implies\:\sf{y\:=\:\dfrac{240}{8}}$

$\implies\:\sf{y\:=\:30}$

$\implies\:\sf\boxed {\red{y\:=\:30A}}$

Therefore, the current drawn is 30 A when the potential difference is increased to 240 V.

Answer 2

Explanation:

answer of this question is 30 A