Electricity and Magnetism - SS2 Physics Past Questions and Answers - page 2
The unit of capacitance is:
Ohms
Volts
Coulombs
Farads
The formula for capacitance is given by:
C = Q / V
C = V / Q
C = ε0A / d
C = QV
When the distance between the plates of a parallel-plate capacitor is halved, the capacitance:
Doubles
Halves
Remains the same
Becomes zero
Capacitors in series have a total capacitance that is:
Equal to the sum of the individual capacitances
Less than the smallest individual capacitance
Greater than the largest individual capacitance
Inversely proportional to the individual capacitances
The energy stored in a charged capacitor is given by:
U = (1/2) CV2
U = (1/2) Q2
U = (1/2) QV
U = (1/2) CV
The dielectric material inserted between the plates of a capacitor:
Increases the capacitance
Decreases the capacitance
Does not affect the capacitance
Makes the capacitor non-functional
A capacitor with a capacitance of 10 μF is connected to a voltage source of 12 V. What is the charge stored on the capacitor?
Q = CV
substituting,
(10 μF) x (12 V) = 120 μC
Two capacitors, C₁ = 5 μF and C₂ = 10 μF, are connected in series. What is the total capacitance of the combination?
The total capacitance, Ctotal, is given by the reciprocal of the sum of the reciprocals of the individual capacitances:
1/Ctotal = 1/C₁ + 1/C₂
= 1/(5 μF) + 1/(10 μF)
= (1/5 + 1/10) μF
= 3/10 μF
Ctotal = 10/3 μF = 3.33 μF
Three capacitors, C₁ = 4 μF, C₂ = 6 μF, and C₃ = 8 μF, are connected in parallel. What is the total capacitance of the combination?
The total capacitance of capacitors in parallel is the sum of the individual capacitances:
Ctotal = C₁ + C₂ + C₃
= 4 μF + 6 μF + 8 μF = 18 μF
A capacitor is charged to a voltage of 200 V and stores a charge of 50 μC. What is the capacitance of the capacitor?
C = Q/V
= (50 μC) / (200 V) = 0.25 μF