Question

Potential difference between 2 terminals of electric heater is 60v when it draws a current of 4 amperes from a source. What current will same heater draw if potential difference is increased to 120v

Answer 1

Answer:

8 Amperes

Explanation:

Given :

• Potential difference between the terminals of the electric heater = 60 volts

• Current drawn by the electric heater = 4 Amperes

To find :

• Current drawn by the electric heater if the potential difference us increased to 120 volts

Using the ohms law :

V=I×R

60=4×R

R=60/4

R=15 ohms

The resistance will remain constant and now potential difference is increased to 120 volts

Using the ohms law :

120=I×15

I=120/15

I=8 Amperes

The current drawn will be equal to 8 Amperes

Answer 2

Given:

• Potential difference = 60V
• Current drawn = 4A

To find:

• Current drawn when the same heater if potential difference is increased to 120V

Solution:

★ Using ohms law

V = I × R

Simplifying

R = V/I

Where

• V : potential difference = 60V
• I : current = 4A
• R : resistance = ?

Substituting the values we have

→ R = 60/4

→ R = 15 ohm

Hence , the resistance will be same.

Now ,. given that resistance is increasedb to 120 here , we need to find current drawn

Using the same law

V = I × R

Simplifying

I = V/R

Substituting V = 120 , R = 15

♦ I = 120/15

♦ I = 8A

Hence, current drawn = 8A