Question

The work done against electric forces in increasing the potential difference of a condenser from $20V$ to $40V$ is $W$ . The work done in increasing its potential difference from $40V$ to $50V$ will be (consider capacitance of capacitor remain constant)

• A. $4W$
• B. $\frac{3W}{4}$
• C. $2W$
• D. $\frac{W}{2}$

Answer 1

The correct option is D $\frac{W}{2}$

Work done is given by:

$W=\Delta V\times It$

$W=\left(40-20\right)It$

$W=20It$

Again work done is,

$W_1=\left(50-40\right)It$

$W_1=10It$

$W_1=\frac{W}{2}$