الفيزياء العامة الجزء الثاني#موقع الفيزياء.كوم

Lectures in General Physics
(a) find the current in each resistor. (b) Calculate the power dissipated
by each resistor and the total power dissipated by the three resistors.
(c) Calculate the equivalent resistance, and the from this result find the
total power dissipated.
Solution
To find the current in each resistors, we make use of the fact that the
potential difference across each of them is equal to 18v, since they are
connected in parallel with the battery.
Applying V=IR to get the current flow in each resistor and then apply P =
I 2 R to get the power dissipated in each resistor.
V 18
2
I1 = = = 6A
⇒ P 1 = I 1 R 1 =108W
R 3
1
V 18
2
I
2
= = = 3A
⇒ P 2 = I 2 R 2 =54W
R 6
2
V 18
2
I
3
= = = 2A
⇒ P 3 = I 3 R 3 =36W
R 9
3
The equivalent resistance R eq is
1
R eq
=
1
3
+
1
6
R eq = 1.6 Ω
+
1
9
=
11
18
Dr. Hazem Falah Sakeek