الفيزياء العامة الجزء الثاني#موقع الفيزياء.كوم

Lectures in General Physics
Example 7.5
An electric heater is constructed by applying a potential difference of
110volt to a nichrome wire of total resistance 8Ω. Find the current
carried by the wire and the power rating of the heater.
Solution
Since V = IR
I V 110 ∴ = = = 13. A
R 8
8
The power P is
P = I 2 R = (13.8) 2 ×8=1520W
Example 7.6
A light bulb is rated at 120v/75W. The bulb is powered by a 120v. Find
the current in the bulb and its resistance.
Solution
P = IV
I P 75 ∴ = = = 0. A
V 120
625
The resistance is
V 120
R = = = 192Ω
I 0.625
Dr. Hazem Falah Sakeek