Three parallel-connected resistors when connected across a DC voltage source dissipate a total power of 72 W. The total current drawn is 6 A.

Three parallel-connected resistors when connected across a DC voltage source
dissipate a total power of 72 W. The total current drawn is 6 A. The current flowing through
the first resistor is 3 A and the second and third resistors have equal values. What are the
resistances of the three resistors? Draw the figure.
 

anisingh259

New member
Let the total resistance is Req and dc voltage is V voltage and total current be I amp then.
Total power P = 72W and I = 6A
V*I = 72
Then V = 12V
Current through first resistor is I1 3A let it resistance is R1 then.
12/R1 = 3
R1= 4
Let second resistance is R2 and current flowing through it is I_2
And third resistance is R3 and current flowing through it is I_3
If second and third resistor have equal value, then equal current will flow through them.
R2 = R3 and I2 = I3
I = I_1 + I_2 + I_3 = I_1 + 2I_2
6 = 3 + 2I_2
I_2 = 3/2
So R2 = V/I2 = 12/1.5 = 8 ohm
So R3 = R2 = 8 ohm
 
Top