Question

A capacitor is charged by a battery and energy stored is 'U'. Now the battery is removed and the distance between plates is increased to four times. The energy stored becomes ______.

Options

• 3U

• 2U

• U

• 4U

Answer 1

A capacitor is charged by a battery and energy stored is 'U'. Now the battery is removed and the distance between plates is increased to four times. The energy stored becomes 4U.

Explanation:

Energy stored `"w"="Q"^2/"2C"`

`"C"=(in_0"A")/"d"`

If d is increased four times, the capacitance becomes one fourth. The charge Q remains same. Hence the energy stored becomes four times.