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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- A. in series with the circuit
- B. in parallel with circuit
- C. in series with any of the parallel resistances in the circuit
- D. in parallel with any of the series resistances in the circuit
Explanation: An ammeter must be placed in series so the same current flowing through the circuit passes through the meter.
Correct answer: in series with the circuit- A. 18Ω
- B. 30Ω
- C. 24Ω
- D. 12Ω
Explanation: The deflection falls from 50 divisions to 25 divisions, so the galvanometer current becomes half its original value.
Correct answer: 12Ω- A. detect current in a circuit
- B. measure current flowing through a circuit
- C. measure voltage across a circuit
- D. measure potential difference between two points in a circuit
Explanation: A galvanometer is a sensitive instrument used to detect the presence and direction of a small current by the deflection of its coil.
Correct answer: detect current in a circuit- A. 2.0 mA
- B. 20 mA
- C. 200 mA
- D. 0.2 mA
Explanation: Using I = V/R, the maximum safe current is I = 100 mV / 50 Ω = 0.100 V / 50 Ω = 0.002 A = 2.0 mA.
Correct answer: 2.0 mA- A. shunt value decreases
- B. shunt value increases
- C. shunt value remains the same
- D. none of the above
Explanation: For a higher ammeter range, more current must bypass the galvanometer, so a smaller shunt resistance is connected in parallel.
Correct answer: shunt value decreases- A. galvanometer
- B. voltmeter
- C. ammeter
- D. AC transformer and DC generator
Explanation: A galvanometer, ammeter and voltmeter are electromechanical measuring instruments because current produces mechanical motion or…
Correct answer: AC transformer and DC generator- A. zero
- B. equal to the restoring couple
- C. greater than the restoring couple
- D. smaller than the restoring couple
Explanation: At equilibrium, the net torque is zero, so the deflecting couple and restoring couple must be equal in magnitude and opposite in…
Correct answer: equal to the restoring couple- A. AA. voltmeter
- B. galvanometer
- C. cathode ray oscilloscope (CRO)
- D. ammeter
Explanation: A CRO has a very high input resistance, so it can measure potential difference while drawing an almost negligible current from the…
Correct answer: cathode ray oscilloscope (CRO)- A. negative charges
- B. positive charges
- C. both negative and positive charges
- D. neutral particles
Explanation: In liquids and ionized gases, both positive ions and negative ions move and contribute to electric current, with conventional current…
Correct answer: both negative and positive charges- A. same current
- B. same current and potential difference
- C. different current but same potential difference
- D. different current and potential differences
Explanation: Parallel appliances are connected across the same two points, so each receives the same potential difference, while the current differs…
Correct answer: different current but same potential difference- A. 3600C
- B. 7200C
- C. 1C
- D. 2C
Explanation: Charge flow is Q = It, so Q = 1 A x 3600 s = 3600 C in one hour. The 2 m length is irrelevant because current already gives charge flow…
Correct answer: 3600C- A. complex network
- B. wheat stone bridge
- C. potential divider
- D. all of above
Explanation: A potential divider uses series resistors to provide an adjustable fraction of the supply potential, giving a continuously varying output…
Correct answer: potential divider- A. Joule effect
- B. Joule Thomsons effect
- C. Comptons effect
- D. Feed back effect
Explanation: The heating of a conductor by current is called the Joule effect, described by the relation H = I²Rt, where heat is produced because…
Correct answer: Joule effect- A. free electrons
- B. protons
- C. neutrons
- D. still under controversy
Explanation: In a metallic conductor, the mobile charge carriers are free electrons, which drift through the lattice when an electric field is applied.
Correct answer: free electrons- A. increase with rise in temperature
- B. decrease with rise in temperature
- C. will remain same
- D. depends upon altitude of experimentation
Explanation: For a metallic wire, increasing temperature increases lattice vibrations, which causes more collisions for electrons and therefore…
Correct answer: increase with rise in temperature- A. 2 ohm
- B. 3 ohm
- C. 2/3 ohm
- D. 3/2 ohm
Explanation: Since we have a uniform wire, therefore the resistance of each side of the triangle will be equal as the length of each is also equal.
Correct answer: 2/3 ohm- A. I2/Rt
- B. I2Rt
- C. I2/R/t
- D. IR2t
Explanation: Work done when an electric charge Q moves against a potential difference is given by,W=QxVSince current is I=Q/tQ=IxtBy ohm's law…
Correct answer: I2Rt- A. Resistance increases with increase of temperature
- B. Resistance decreases with increase of temperature
- C. Resistance decreases with decrease of temperature
- D. Resistance remains same with increase of temperature
Explanation: When resistance increase with an increase in temperature, the material is said to have a positive temperature coefficient.
Correct answer: Resistance increases with increase of temperature- A. Tungsten
- B. Carbon
- C. Nichrome
- D. Platinum
Explanation: Correct option is B.A negative coefficient for a material means that its resistance decreases with an increase in temperature.
Correct answer: Carbon- A. °C
- B. °C-1
- C. m0C-1
- D. None of these
Explanation: Correct option is B.The temperature coefficient of resistance (TCR) measures the change in resistance expressed in degrees Celsius.
Correct answer: °C-1