Introduction:
In an electrical circuit, a capacitor is a passive two-terminal electronic component that stores electrical energy in an electric field. When a voltage is applied across a capacitor, it charges and stores energy. The charge stored in a capacitor is directly proportional to the applied voltage.

Explanation:
When the voltage across a capacitor increases, the charge stored in it also increases. This can be understood by considering the behavior of a capacitor in response to a changing voltage.

Capacitance and Charge:
The charge stored in a capacitor is given by the equation Q = CV, where Q is the charge stored, C is the capacitance of the capacitor, and V is the voltage across the capacitor. The capacitance is a constant value that depends on the physical characteristics of the capacitor, such as its size, shape, and dielectric material.

Effect of Increasing Voltage:
When the voltage across a capacitor increases, the electric field between the capacitor plates strengthens. This causes more charge to be stored in the capacitor. This relationship between voltage and charge is linear, meaning that if the voltage doubles, the charge stored also doubles.

Example:
Consider a capacitor with a capacitance of 1 microfarad (1μF). If a voltage of 5 volts is applied across the capacitor, the charge stored can be calculated using the equation Q = CV. In this case, Q = (1μF)(5V) = 5μC (microcoulombs). If the voltage is then increased to 10 volts, the charge stored would be Q = (1μF)(10V) = 10μC, which is twice the previous charge.

Conclusion:
When the voltage across a capacitor increases, the charge stored in it also increases. This is due to the direct relationship between voltage and charge in a capacitor. It is important to note that the capacitance remains constant, and it is the voltage that affects the charge stored.