A capacitor consisting of two parallel plates, separated by a distance d is init

Question

A capacitor consisting of two parallel plates, separated by a distance d is initially charged to a voltage of 5.5 V. The battery is then disconnected from the capacitor. For each statement below, select True or False.

If the battery is disconnected, and then the distance d between the plates is decreased, the voltage across the capacitor will increase.

If the battery is disconnected, and then the distance d between the plates is decreased, the amount of charge stored on either plate of the capacitor will change.

Decreasing the distance d after disconnecting the battery will decrease the electrical energy stored in the capacitor.

Explanation / Answer

Remember and apply for parallel plate caapcitor, these as formulas

1. Capacitance C = K eoA/d

where K is dieelctric constant   ( for air K = 1)

eo is permnittivity constant = 8.85 e-12

A is area = pi^2   ( for circular plates)    and   l* b   for rectanular plates

and

d is the distance between the plates

2.Charge Q = CV     where V is potrntial difference

3. energy stored U = 0.5 QV      or 0.5 CV^2    or 0.5 Q^2/C

4. electric field between the plates is E = Q/eo A

( also given by E = V/d)

so here we get after appling

If the battery is disconnected, and then the distance d between the plates is decreased, the voltage across the capacitor will increase.------false

If the battery is disconnected, and then the distance d between the plates is decreased, the amount of charge stored on either plate of the capacitor will change.----------true

Decreasing the distance d after disconnecting the battery will decrease the electrical energy stored in the capacitor.-------------false

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.