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 53 of 53
- A. 3.21 × 10^18
- B. 2.2 × 10^16
- C. 1.602 × 10^19
- D. 6.42 × 10^18
Explanation: To find the number of electrons involved in a current of 1 A, we use the formula:I = n × ewhere I is the current (1 A), n is the number of…
Correct answer: 6.42 × 10^18- A. Resistance and resistivity
- B. Conductivity and resistivity
- C. Electromotive force and potential difference
- D. Resistivity and temperature coefficient of resistivity
Explanation: The correct answer is Option C: Electromotive force and potential difference. Both are measured in volts (V) and have the same dimensions.
Correct answer: Electromotive force and potential difference- A. Their bodies have high resistance
- B. Their feet are good insulators
- C. There is a negligible potential difference between their feet
- D. Wires are insulated
Explanation: Birds perched on an overhead transmission line are not harmed because both of their feet are at the same electrical potential, eliminating…
Correct answer: There is a negligible potential difference between their feet- A. Charge
- B. Energy
- C. Mass
- D. Momentum
Explanation: Kirchhoff's first law is a manifestation of law of conservation of charge, if there is no sink or source of charge at a point, the total…
Correct answer: Charge- A. Cross sectional of the sample
- B. The length of sample
- C. The mass of an electron
- D. The electric field in the sample
Explanation: Drift velocity is proportional to current. In a resistive material, it is also proportional to the magnitude of an external electric…
Correct answer: The electric field in the sample1046. The sum of the e.m.f and potential differences around a closed circuit is zero is a consequence of:
- A. Ohm's law
- B. Newton's 2nd law
- C. Conservation of energy
- D. Conservation of charge
Explanation: The second law of Kirchoff states that around any closed loop in a circuit, the sum of potential differences and emf is zero.
Correct answer: Conservation of energy- A. 7A out of the junction
- B. 7A into the junction
- C. 3A out of the junction
- D. 3A in to the junction
Explanation: D. Kirchoff's Junction rule states that the total current into a junction is equal to that out of the junction hence 3+4in = 5+2out
Correct answer: 3A in to the junction- A. 0.25 Ω in parallel
- B. 0.25 Ω in series
- C. 0.50 Ω in parallel
- D. 0.50 Ω in series
Explanation: A galvanometer is converted into an ammeter by connecting a low resistance in parallel with the galvanometer.
Correct answer: 0.25 Ω in parallel- A. 0.12V
- B. 2.0V
- C. 6.0V
- D. 24V
Explanation: The correct answer is 6.0V, determined by using the formula P = VI, where P is power, V is voltage, and I is current.
Correct answer: 6.0V- A. Mass
- B. Energy
- C. Momentum
- D. Charge
Explanation: Kirchhoff's current law (KCL) is based upon the law of conservation of charge.
Correct answer: Charge- A. 560
- B. 300
- C. 200
- D. 800
Explanation: To calculate the rate of energy dissipation (power) in an X-ray tube, we use the formula P = IV, where P is the power in watts, I is the…
Correct answer: 300- A. Positive
- B. Negative
- C. Imaginary
- D. Zero
Explanation: The temperature coefficient of resistance for a semiconductor is negative, indicating that its resistance decreases as temperature…
Correct answer: Negative