An ideal parallel-plate capacitor consists of a set of two parallel plates of area separated by a very small distance 푑. this capacitor is connected to a battery that charges the capacitor such that the energy stored in the capacitor is 푈'. now the battery is disconnected and the separation between the plates is doubled, how much energy is stored in the capacitor?

doubled the initial value

Explanation:

Let the area of plates be A and the separation between them is d.

Let V be the potential difference of the battery.

The energy stored in the capacitor is given by

U = Q^2/2C   ...(1)

Now the battery is disconnected, it means the charge is constant.

the separation between the plates is doubled.

The capacitance of the parallel plate capacitor is inversely proportional to the distance between the plates.

C' = C/2

the new energy stored

U' = Q^2 /  2C'

U' = Q^2/C = 2 U

The energy stored in the capacitor is doubled the initial amount.

the answer is b

explanation:

when jerome paddle in flowing river towards east the net speed of jerome will increase

so the net speed of jerome will be given as

now the speed of paul will be same as it is given as he is running on the ground

so

so here we can say since the speed of jerome is more so he will win the race

now as we know the distance so the time difference is given as

so jerome will reach first and the time difference will be 203.55 s or 3.4 min