Step 1:

(1.1.1)

A resistance of is connected in parallel with resistor.

If two resistors    connected in parallel, then equivalent resistor is given by,

.

Substitute and in the above formula.

This  resistance comes in series with unknown resistor and circuit is connected to 10 V supply.

If the two resistors are in series, then equivalent resistor is given by,

.

Substitute  and in the above formula.

.

When a 2 A current is drawn from the supply of 10 V.

From the ohms law: .

Substitute and in above formula.

This resistance is equal to the equivalent resistance.

Therefore value of the unknown resistor is when 2 A current is drawn from the source.

Step 2:

Power dissipated in the circuit:

Power dissipated in the circuit with current drop and supply voltage is given by,

.

Substitute and in the above formula.

Power dissipated in the circuit is 20 watt.

Solution:

The value of the unknown resistor is when 2 A current is drawn from the source.

Power dissipated in the circuit is 20 watt.