Free Current Electricity MCQs with Answers
1,052 Current Electricity MCQs from Physics, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
Steady current relates charge flow to potential difference, resistance and resistivity, including how temperature changes a conductor's resistance. Sources with internal resistance have terminal voltage below their emf when delivering current, and maximum power output occurs under a specific load condition rather than at zero resistance.
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1,052 questions · page 12 of 53
- A. 2Ω
- B. 3Ω
- C. 8Ω
- D. 24Ω
Explanation: Each part has resistance 24/3 = 8 Ω. For three parts in parallel: 1/Rₑ𝑞 = 1/8 + 1/8 + 1/8 = 3/8, so Rₑ𝑞 = 8/3 ≈ 2.67 Ω, closest to 3 Ω.
Correct answer: 3Ω- A. 4.5 V
- B. 7V
- C. 8V
- D. 9V
Explanation: Net emf = 12 - 6 = 6 V. Total resistance = 1 + 2 + 9 = 12 Ω. Current I = 6/12 = 0.5 A. Voltage across 9 Ω = I × R = 0.5 × 9 = 4.5 V.
Correct answer: 4.5 V- A. 8Ω
- B. 12Ω
- C. 18Ω
- D. 24Ω
Explanation: For a balanced Wheatstone bridge, R₁/R₂ = R₃/Rₓ. Using 6/9 = 12/Rₓ, we get Rₓ = 12 × 9/6 = 18 Ω.
Correct answer: 18Ω- A. 1V
- B. 1.2V
- C. 1.5V
- D. 2V
Explanation: Potential gradient = V/L = 6/1.5 = 4 V/m. EMF of the cell = gradient × balance length = 4 × 0.3 = 1.2 V.
Correct answer: 1.2V- A. R1 × R2 = R3 ×R4
- B. R1×R3= R2×R4
- C. R1×R4= R2×R3
- D. None of the above
Explanation: The given circuit resembles a Wheatstone bridge, which is a configuration used to measure unknown resistances or to create a balanced…
Correct answer: R1×R4= R2×R3- A. Option A
- B. Option B
- C. Option C
- D. Option D
Explanation: A voltmeter is always connected in parallel, and an ammeter is always connected in series.
Correct answer: Option A- A. 10cm
- B. 20cm
- C. 30cm
- D. 40cm
Explanation: X=12ΩInitial R=18 ΩNew R=8Meter bridge length = 100 cmLet the distance AJ be y1 before shifting and y2 after shifting.Before shifting…
Correct answer: 20cm- A. Heat generated is constant over time
- B. Heat generated decreases linearly with time
- C. Heat generated increases proportionally with time
- D. Heat generated decreases exponentially with time
Explanation: This option is correct. The heat generated in a resistor is given by the equation Q = I²RT, where I is the current, R is the resistance…
Correct answer: Heat generated increases proportionally with time- A. 5/31 A
- B. 6/31 A
- C. 4/31 A
- D. None of these
Explanation: Using nodal analysis at node b (taking node a as reference with voltage Va = 0), the sum of currents leaving node b is (Vb - 1.5)/1 + (Vb…
Correct answer: 5/31 A- A. 3V
- B. 1V
- C. 4V
- D. 5V
Explanation: Option A is correct. Applying KCL at point O allows us to determine that the potential is 3 V.
Correct answer: 3V- A. A
- B. B
- C. First A then B
- D. It will remain at C
Explanation: As current flows, heat will be produced in the circuit. So, R will decrease. So, the balance point will shift towards the left.
Correct answer: A- A. 100Ω
- B. 200Ω
- C. 300Ω
- D. 400Ω
Explanation: V A- V B= 3V = i 1Yi1 = 12/100 + 800 + Y = 12/900+ Yi 1Y=312Y/900+ Y = 3Y = 300ΩHence, option C is correct.
Correct answer: 300Ω- A. 1A
- B. 2A
- C. Zero
- D. 0.5A
Explanation: The given circuit is a balanced Wheatstone bridge. So, the current through the 5Ω resistor is zero.
Correct answer: Zero- A. 25cm
- B. 75cm
- C. 50cm
- D. 40cm
Explanation: The potential gradient in the wire PQ is two‑thirds of the emf E divided by the length 100 cm.
Correct answer: 75cm- A. Negative charges
- B. Neutral particle
- C. Positive charges
- D. Both negative and positive charges
Explanation: In liquids and gases, current is typically due to the motion of both negative (electrons) and positive (ions) charges.
Correct answer: Both negative and positive charges- A. The flow of electric charge
- B. Moving protons
- C. Insulating materials
- D. Neutrons
Explanation: The electronics current is due to the flow of electric charge through a conductive medium, such as wires or semiconductors.
Correct answer: The flow of electric charge- A. Electrons
- B. Atoms
- C. Protons
- D. Molecules
Explanation: Electric current in a wire involves the movement of electrons.
Correct answer: Electrons- A. P.E of the atoms
- B. K.E of the atoms
- C. Atomic size
- D. Number of protons
Explanation: When electric current passes through conductors, it primarily increases the kinetic energy (K.E) of the atoms in the conductor.
Correct answer: K.E of the atoms- A. 0.20 C
- B. 2.5 C
- C. 5.0 C
- D. 10.0 C
Explanation: When a 4-volt potential difference is applied across a resistor, causing 10 joules of energy to be converted, 2.5 coulombs of charge flow…
Correct answer: 2.5 C- A. Circular motion
- B. Linear motion
- C. Random motion
- D. None of above
Explanation: Free electrons inside metallic conductors move randomly (option C) due to collisions with atoms and other electrons, rather than following…
Correct answer: Random motion