Question

Find the power dissipated through 3 ohm resistor​

Answer 1

3watt is the right answer

Answer 2

Answer:

The power dissipated through 3 Ω  resistor​ is 3 watt i.e.option(4).

Explanation:

We will use the following formulas to solve this question,

$P=\frac{V^2}{R}$                 (1)           (For parallel combination)

$P=I^2R$              (2)           (For series combination)

Where,

P=power of the resistor

V=voltage across the resistor

R=resistance of the resistor

From the question we have,

The power dissipated across the 8Ω resistor is 2W.

So, by using equation (1) we get;

$2=\frac{V^2}{8}$

$V=\sqrt{16}=4volt$      (3)

Since 8Ω resistor is connected in parallel combination with 1Ω and 3Ω resistors then voltage across them will also be 4 volt.

So, the equivalent resistance of the resistors 1Ω and 3Ω is ,

$R_s=1\Omega+3\Omega=4\Omega$     (4)

And the current through the combination of resistors  1Ω and 3Ω is,

$I=\frac{4}{4}=1A$     (5)

So the power across 3Ω resistor is given as,

$P=(1)^2\times 3=3Watt$                 (by using equation (2))

Hence, the power dissipated through 3 Ω  resistor​ is 3 watt i.e.option(4).