A capacitor has a potential difference of V applied across its plates. If the potential difference across its plates is increased to 2V, the energy stored in the capacitor is: A) reduced to half
B) doubles
C) reduced to one fourth
D) quadruples (four times bigger)
E) None of the above

Respuesta :

Answer:

Option B. doubles

Explanation:

This can be explained by the definition of capacitance that charge on the capacitor will remain constant irrespective of the voltage applied.

This can be given as:

Q ∝ V or Q = CV

where,

Q = charge

V = Voltage

C = Capacitance

So, when V is doubled, C shoul reduce to half to main constant charge on the capacitor:

V' = 2V

C' = [tex]\frac{1}{2}C[/tex]

Also , Energy stored in a capacitor, E is given by:

E = [tex]\frac{1}{2}CV^{2}[/tex]                             (1)

Now, when

V' = 2V

C' = [tex]\frac{1}{2}C[/tex]

Using eqn (1):

E' = [tex]\frac{1}{2}C'V'^{2}[/tex]

Energy, E' = [tex]\frac{1}{4}C(2V)^{2}[/tex]

E' = [tex]CV^{2}[/tex] = 2E

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