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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661. A plausible reason for the increase in resistivity of most of the conductors with temperature is:
- A. The mass of the electron changes with temperature
- B. The charge on each electron changes with temperature
- C. The electron density changes with temperature
- D. The time between collisions changes with temperature
Explanation: This option is plausible. In conductors, the resistivity is often influenced by the scattering of electrons as they move through the…
Correct answer: The time between collisions changes with temperature- A. 50 W
- B. 100 W
- C. 200W
- D. 300W
Explanation: Among the given options, the 300W bulb has the highest power rating. As per the formula P= V^2/R, a higher power rating corresponds to…
Correct answer: 300W- A. E=I2R
- B. E=IR
- C. E=R/I
- D. E=I/R
Explanation: The emf is given by relation E=IR.Ohm's law states that the current through a conductor between two points is directly proportional to the…
Correct answer: E=IR- A. watt × second
- B. volt × meter
- C. volt per coulomb
- D. Newton per meter
Explanation: The unit of power is the watt, and hence the unit of energy is watt-second since energy is the product of power and time.
Correct answer: watt × second- A. The resistance will be halved and the specific resistance will remain unchanged
- B. The resistance will be doubled and the specific resistance will be halved
- C. The resistance will be halved and the specific resistance will be doubled
- D. The resistance and the specific resistance will both remain unchanged
Explanation: When the length and radius of the wire are both doubled, we apply the formula for resistance: R=ρ×L/A.
Correct answer: The resistance will be halved and the specific resistance will remain unchanged- A. 1.6 x 10^-26 A
- B. 1.6 x 10^12 A
- C. 1.6 x 10^-12 A
- D. 107 A
Explanation: This option correctly states that the current flowing through the conductor is 1.6×10−12 amperes.
Correct answer: 1.6 x 10^-12 A- A. 10-3 m s-1
- B. 1 ms-¹
- C. 10 ms -1
- D. 1000 km s -1
Explanation: The value of drift velocity is 10-3 m/s.This is the velocity of electrons moving through a conductor when an electric field is applied.
Correct answer: 10-3 m s-1- A. 5
- B. 12
- C. 1/12
- D. 300
Explanation: Q=ItAccording to the question:Q=5×60=300 CHence, this option is correct.
Correct answer: 300- A. Unchanged
- B. Halved
- C. Doubled
- D. 1/4 of the original value
Explanation: This option correctly states that doubling the length of the wire will halve its conductance.
Correct answer: Halved670. Three 6 Ω are connected as shown in the diagram What is the resistance between points 'A' and 'B'
- A. 6 Ω
- B. 16 Ω
- C. 4 Ω
- D. 2 Ω
Explanation: If looked into closely, these resistors are actually parallel to each other.The total resistance is equal…
Correct answer: 2 Ω- A. 3.0 C, 1.25 x 10^19
- B. 2.0 C, 1.25 x 10^19
- C. 4.0 C, 1.25 x 10^19
- D. 2.0 C, 5.25 x 10^19
Explanation: The current flowing through a wire is defined as the charge passing through a cross-section of the wire per unit time, given by the…
Correct answer: 2.0 C, 1.25 x 10^19- A. From A to B
- B. From B to A
- C. 0
- D. Cannot say unless the resistance of the galvanometer is given
Explanation: Given:Left branch:Top: R1=10 ΩBottom: R2=5 ΩRight branch:Top: R3=5 ΩBottom: R4=10 ΩStep 1: Check the balance condition of the Wheatstone…
Correct answer: From A to B- A. Temperature of the conductor becomes infinite
- B. Temperature of the conductor increases
- C. Temperature of the conductor decreases
- D. Temperature of the conductor remains same
Explanation: "The current flowing through a conductor is directly proportional to potential difference across its ends provided the physical state such…
Correct answer: Temperature of the conductor remains same- A. In parallel to the external load
- B. In series to the external load
- C. Not connected to the external load
- D. Zero
Explanation: The internal resistance of a battery is in series to external load. Hence option B is correct.
Correct answer: In series to the external load- A. Potential difference
- B. EMF
- C. Internal potential energy
- D. Terminal voltage
Explanation: The correct answer is terminal voltage, which specifically refers to the voltage across the terminals of a battery when it is connected to…
Correct answer: Terminal voltage- A. R/2
- B. R
- C. 4R
- D. 2R
Explanation: As R = ρL/A R ∝ L If length is doubled then R is also doubled, so R =2R. Hence, option D is correct
Correct answer: 2R- A. Joule"s law
- B. Gauss's law
- C. Ohm's law
- D. Ampere"s law
Explanation: Ohm's law states that the current through a conductor between two points is directly proportional to the voltage across the two points as…
Correct answer: Ohm's law- A. Double
- B. Half
- C. Remains same
- D. Four times
Explanation: Resistivity of wire remains constant. As the length of wire gets doubled, the cross-sectional area will become half of its previous value…
Correct answer: Remains same- A. Increases
- B. Decreases
- C. Remain same
- D. Infinite
Explanation: The electrons get excited and jump from the valance band into the conduction band and thereby increases conductance resulting in the…
Correct answer: Decreases- A. Cross-sectional area of the conductor in m2
- B. Product of the length of the conductor in meters
- C. Resistivity of the material in units of ohm meters
- D. Resistance of the conductor in units of ohms per meter
Explanation: The symbol "p" in the formula represents the resistivity of the material in units of ohm meters.
Correct answer: Resistivity of the material in units of ohm meters