(a) How much current will an electric bulb draw from a 220 V source, if the resistance of the bulb filament is 1200 Ω? (b) How much current will an electric heater coil draw from a 220 V source, if the resistance of the heater coil is 100 Ω?
Example 12.3 (a) How much current will an electric bulb draw from a 220 V source, if the resistance of the bulb filament is 1200 Ω? (b) How much current will an electric heater coil draw from a 220 V source, if the resistance of the heater coil is 100 Ω?
Potential difference = V = 220 V
By ohm’s law,
V = I R
∴ 𝑉/𝑅 = I
I = 𝑉/𝑅
R = 1200 Ω
I = 𝑉/𝑅
I = 220/1200
I = 22/120
I = 11/60
I = 0.18 A
R = 100 Ω
I = 𝑉/𝑅
I = 220/100
I = 22/10
I = 2.2 A
Current through bulb filament of 1200 Ω is 0.18 A
Current through bulb filament of 100 Ω is 2.2 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.