When a charge Q on a capacitor is doubled, then energy stored U will be:

Explanation

The energy stored in a capacitor (U) is given by the formula:U = (1/2) * C * V^2where C is the capacitance of the capacitor and V is the voltage across the capacitor.When a charge (Q) on a capacitor is doubled, the voltage (V) across the capacitor remains the same if the capacitance (C) is constant. This is because the capacitance of a capacitor is defined as the ratio of charge to voltage, and if the charge is doubled while the voltage remains the same, the capacitance remains unchanged.So, in this case, if Q is doubled, the voltage V remains the same. Substituting this into the formula for energy stored in a capacitor:U = (1/2) * Q^2/CSince V remains constant, the energy stored U is proportional to the square of the charge Q. Thus, when the charge on a capacitor is doubled, the energy stored in the capacitor will be quadrupled (i.e., multiplied by a factor of 4).