(i) In the First Case:
Potential difference, V = 6 V
And, Net Resistance, R= 1 + 2 = 3 (Resistors are connected in series)
Now, by Ohm’s law:
Thus, the current flowing in the circuit containing 1 and 2 resistors in series is 2 A. In a series circuit, the same current flows throughout the circuit. So, the current flowing through the 2 resistor is also 2A. Now, we know that the current (in 2 resistor) is 2 A and its resistance is 2 .
Now, Power used in 2 resistor is given as:
(ii) In the Second Case:
Here, 4 V battery is attached across the parallel combination of 12 and 2 resistors, so the potential difference across the 2 resistor will also be 4 V. Because in parallel connection
Voltage is same.
Now, Potential difference, V= 4 V
And Resistance, R = 2
So, Power used in 2 resistor, P= =
Thus, the power used in the 2 resistor in the second case is also 8W.
From both the cases we can say that the 2 resistor uses equal power in both the circuits.
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