The potential difference between the terminals of an electric heater is 60 V when it draws a current of 4 A from the source. What current will the heater draw if the potential difference is increased to 120 V?
Example 12.4 The potential difference between the terminals of an electric heater is 60 V when it draws a current of 4 A from the source. What current will the heater draw if the potential difference is increased to 120 V?
Potential difference = V = 60 V
Current = I = 4 A
By ohm’s law,
V = I R
𝑉/I = R
R = 𝑉/I
R = 60/4
R = 15 Ω
Now,
the potential difference is increased 120 V
We need to find current (I) drawn
Now,
Potential difference = V = 120 V
Resistance = 15 Ω
By ohm’s law,
V = I R
𝑉/I = R
I = 𝑉/R
I = 120/15
I = 8 A
Current through the heater is 8 A
Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 9 years. He provides courses for Maths and Science at Teachoo.
