Coulombs Law and Electric Field - Exam Prep Insights

Coulombs Law and Electric Field - Transient Response in RC Circuits

Q. If a 10 V battery is connected to a 5 Ω resistor, what is the current flowing through the resistor?

A. 2 A
B. 0.5 A
C. 5 A
D. 10 A

Solution

Using Ohm's law, I = V/R = 10 V / 5 Ω = 2 A.

Correct Answer: A — 2 A

Learn More →

Q. If a 12 V battery is connected to a 3 Ω resistor, what is the current flowing through the circuit?

A. 2 A
B. 3 A
C. 4 A
D. 5 A

Solution

Using Ohm's law, I = V/R = 12 V / 3 Ω = 4 A.

Correct Answer: A — 2 A

Learn More →

Q. If a resistor of 10 Ω is connected in series with a 5 Ω resistor, what is the total resistance?

A. 15 Ω
B. 5 Ω
C. 10 Ω
D. 20 Ω

Solution

Total resistance in series is R_total = R1 + R2 = 10 Ω + 5 Ω = 15 Ω.

Correct Answer: A — 15 Ω

Learn More →

Q. In a parallel circuit with a 12 V battery, what is the voltage across each branch?

A. 12 V
B. 6 V
C. 24 V
D. 0 V

Solution

In a parallel circuit, the voltage across each branch is equal to the source voltage, which is 12 V.

Correct Answer: A — 12 V

Learn More →

Q. In a series RC circuit, what happens to the current as the capacitor charges?

A. Increases
B. Decreases
C. Remains constant
D. Oscillates

Solution

As the capacitor charges, the current decreases exponentially until it approaches zero.

Correct Answer: B — Decreases

Learn More →

Q. In an RC circuit, what is the time constant if R = 2 kΩ and C = 10 µF?

A. 20 ms
B. 2 ms
C. 200 ms
D. 0.2 s

Solution

Time constant τ = R * C = (2000 Ω) * (10 x 10^-6 F) = 0.02 s = 20 ms.

Correct Answer: A — 20 ms

Learn More →

Q. In an RC circuit, what is the time constant if R = 4 kΩ and C = 10 µF?

A. 40 ms
B. 20 ms
C. 30 ms
D. 50 ms

Solution

Time constant τ = R * C = 4000 Ω * 10 x 10^-6 F = 40 ms.

Correct Answer: A — 40 ms

Learn More →

Q. What is the charge stored in a capacitor of 5 µF at a voltage of 10 V?

A. 50 µC
B. 100 µC
C. 25 µC
D. 75 µC

Solution

Charge Q = C * V = 5 x 10^-6 F * 10 V = 50 µC.

Correct Answer: A — 50 µC

Learn More →

Q. What is the charge stored in a capacitor of 5 µF when connected to a 10 V battery?

A. 0.05 mC
B. 0.1 mC
C. 0.2 mC
D. 0.5 mC

Solution

Charge Q = C * V = 5 x 10^-6 F * 10 V = 0.05 mC.

Correct Answer: B — 0.1 mC

Learn More →

Q. What is the electric field inside a parallel plate capacitor with a potential difference of 100 V and plate separation of 0.01 m?

A. 10000 N/C
B. 1000 N/C
C. 100 N/C
D. 10 N/C

Solution

E = V/d = 100 V / 0.01 m = 10000 N/C.

Correct Answer: A — 10000 N/C

Learn More →

Q. What is the electric field strength at a distance of 0.2 m from a point charge of +5 µC?

A. 112.5 N/C
B. 112.5 kN/C
C. 25 N/C
D. 25 kN/C

Solution

E = k * |q| / r^2 = (8.99 x 10^9 N m²/C²) * (5 x 10^-6 C) / (0.2 m)^2 = 112.5 N/C.

Correct Answer: A — 112.5 N/C

Learn More →

Q. What is the electric field strength at a distance of 2 m from a +5 µC point charge?

A. 1.125 N/C
B. 2.25 N/C
C. 0.5625 N/C
D. 0.75 N/C

Solution

E = k * |q| / r^2 = (8.99 x 10^9 N m²/C²) * |5 x 10^-6 C| / (2 m)^2 = 1.125 N/C.

Correct Answer: B — 2.25 N/C

Learn More →

Q. What is the electric potential energy of a system of two charges of +1 µC and -1 µC separated by 0.1 m?

A. -0.09 J
B. 0.09 J
C. 0.18 J
D. 0.36 J

Solution

Potential energy U = k * q1 * q2 / r = (8.99 x 10^9 N m²/C²) * (1 x 10^-6 C) * (-1 x 10^-6 C) / 0.1 m = -0.09 J.

Correct Answer: B — 0.09 J

Learn More →

Q. What is the electric potential energy of a system of two charges, +1 µC and -1 µC, separated by 0.1 m?

A. -0.09 J
B. 0.09 J
C. 0.18 J
D. 0.36 J

Solution

Potential energy U = k * q1 * q2 / r = (8.99 x 10^9 N m²/C²) * (1 x 10^-6 C) * (-1 x 10^-6 C) / 0.1 m = -0.09 J.

Correct Answer: A — -0.09 J

Learn More →

Q. What is the energy stored in a capacitor of 20 µF charged to 12 V?

A. 1.44 mJ
B. 0.12 mJ
C. 0.24 mJ
D. 0.48 mJ

Solution

Energy stored, U = 0.5 * C * V^2 = 0.5 * (20 x 10^-6 F) * (12 V)^2 = 1.44 mJ.

Correct Answer: A — 1.44 mJ

Learn More →

Q. What is the equivalent capacitance of two capacitors, 4 µF and 6 µF, in series?

A. 2.4 µF
B. 10 µF
C. 1.5 µF
D. 3.6 µF

Solution

1/C_total = 1/C1 + 1/C2 = 1/4 + 1/6 = 5/12, thus C_total = 12/5 = 2.4 µF.

Correct Answer: A — 2.4 µF

Learn More →

Q. What is the equivalent resistance of three resistors of 2 Ω, 3 Ω, and 6 Ω in series?

A. 11 Ω
B. 10 Ω
C. 9 Ω
D. 8 Ω

Solution

R_eq = R1 + R2 + R3 = 2 Ω + 3 Ω + 6 Ω = 11 Ω.

Correct Answer: A — 11 Ω

Learn More →

Q. What is the potential difference across a 10 µF capacitor charged to 5 V?

A. 0.05 J
B. 0.05 C
C. 0.05 V
D. 0.05 F

Solution

The potential difference is simply the voltage, which is 5 V.

Correct Answer: C — 0.05 V

Learn More →

Q. What is the potential difference across a 20 Ω resistor carrying a current of 2 A?

A. 40 V
B. 20 V
C. 10 V
D. 30 V

Solution

Using Ohm's law, V = I * R = 2 A * 20 Ω = 40 V.

Correct Answer: A — 40 V

Learn More →

Q. What is the total capacitance of two capacitors of 4 µF and 6 µF in parallel?

A. 10 µF
B. 24 µF
C. 2.4 µF
D. 0.4 µF

Solution

In parallel, C_eq = C1 + C2 = 4 µF + 6 µF = 10 µF.

Correct Answer: A — 10 µF

Learn More →

Q. What is the voltage across a capacitor after 3 time constants if it was charged to 12 V?

A. 12 V
B. 8 V
C. 4 V
D. 0 V

Solution

After 3 time constants, a capacitor is considered fully charged, so the voltage remains at 12 V.

Correct Answer: A — 12 V

Learn More →

Q. What is the voltage across a capacitor after 3 time constants in an RC circuit with a supply voltage of 12 V?

A. 12 V
B. 8 V
C. 4 V
D. 0 V

Solution

Voltage across capacitor V(t) = V0 * (1 - e^(-t/τ)). After 3τ, V(3τ) = 12 V * (1 - e^(-3)) ≈ 12 V * (1 - 0.05) ≈ 11.4 V.

Correct Answer: B — 8 V

Learn More →

Showing 1 to 22 of 22 (1 Pages)

Coulombs Law and Electric Field - Transient Response in RC Circuits

On a scale of 0–10, how likely are you to recommend The Soulshift Academy?