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 48 of 53
- A. 2.5 Ω.
- B. 5 Ω.
- C. 20 Ω.
- D. 40 Ω.
Explanation: 5 / 20 = 10 / R4To find R4, we can cross-multiply:5 * R4 = 20 * 105 * R4 = 200R4 = 200 / 5R4 = 40 ΩTherefore, the unknown resistance R4 is…
Correct answer: 40 Ω.- A. increase.
- B. decrease.
- C. become zero.
- D. remain constant.
Explanation: The resistance (R) of a metallic wire is directly proportional to its length (L) and resistivity (ρ), and inversely proportional to its…
Correct answer: increase.- A. 5.0 x 10^2 Ω
- B. 5.0 x 10^3 Ω
- C. 5.0 x 10^5 Ω
- D. 5.0 x 10^7 Ω
Explanation: The value of the first color in a color-coded resistor represents the first digit, the second color represents the second digit, and the…
Correct answer: 5.0 x 10^7 Ω- A. 20.18 Ω.
- B. 44.40 Ω.
- C. 870.0 Ω.
- D. 1310.0 Ω.
Explanation: The correct answer is 20.18 Ω. To find the resistance of the air conditioner, we use the formula Resistance = Voltage^2 / Power.
Correct answer: 20.18 Ω.- A. less than 0 A.
- B. equal to 0 A.
- C. equal to 1 A.
- D. more than 1 A.
Explanation: When the ratio of resistances in a Wheatstone bridge satisfies the condition R1/R2 = R3/R4, the bridge is said to be balanced.
Correct answer: equal to 0 A.- A. R/3
- B. R
- C. 3R
- D. R - 3
Explanation: When a metallic conductor of resistance R is cut into three equal parts, the length of each part becomes one-third of the original length.
Correct answer: R/3- A. current.
- B. voltage.
- C. resistance.
- D. conductance.
Explanation: An ohmmeter is specifically designed to measure resistance in an electrical component.
Correct answer: resistance.- A. increases.
- B. decreases.
- C. becomes 0oC.
- D. remains constant.
Explanation: When a filament lamp behaves like an Ohmic conductor, its resistance increases with temperature.
Correct answer: increases.- A. rheostat.
- B. voltmeter
- C. galvanometer
- D. Wheatstone bridge
Explanation: The correct answer is the Wheatstone bridge because it is a device commonly used to measure unknown resistance values accurately.
Correct answer: Wheatstone bridge- A. Option A: Wire X has higher resistance but the same resistivity as Wire Y.
- B. Option B: Wire X and Wire Y have different resistivities.
- C. Option C: Wire X and Wire Y have the same resistance.
- D. Option D: Wire X has lower resistance but higher resistivity than Wire Y.
Explanation: The correct answer is Option A. Since both wires X and Y are made of the same material, they inherently have the same resistivity.
Correct answer: Option A: Wire X has higher resistance but the same resistivity as Wire Y.- A. Permittivity
- B. Conductivity
- C. Power dissipation
- D. Internal resistance
Explanation: The reciprocal of the resistivity of a material is called conductivity.
Correct answer: Conductivity- A. 1 Ω.
- B. 10 Ω.
- C. 100 Ω.
- D. 1000 Ω.
Explanation: To determine the resistance of the electrical instrument, use the formula for power dissipation in terms of current and resistance: P = I2…
Correct answer: 1 Ω.- A. Length of the wire.
- B. Conductivity of the wire.
- C. Colour and texture of the wire.
- D. Area of cross section of the wire.
Explanation: The resistance of a wire is directly proportional to its length and inversely proportional to its cross-sectional area and the material's…
Correct answer: Length of the wire.- A. Increases.
- B. Decreases.
- C. Becomes 0⁰C.
- D. Remains constant.
Explanation: A filament lamp behaves like an Ohmic conductor when its resistance remains constant, which occurs when its temperature remains constant.
Correct answer: Remains constant.- A. The most sensitive galvanometer is used.
- B. A varying voltage is provided by a source.
- C. A known high resistance box is used in the circuit.
- D. The balance point is close to the middle of the wire.
Explanation: The most accurate measurement of an unknown resistance using a slide wire bridge is achieved by using the most sensitive galvanometer…
Correct answer: The most sensitive galvanometer is used.- A. becomes zero
- B. doubles
- C. remain the same
- D. changes the sign
Explanation: When the hot and cold junctions of a thermocouple are interchanged, the thermo-electromotive force (EMF) changes sign.
Correct answer: changes the sign- A. 1%
- B. 2%
- C. 4%
- D. 0.5%
Explanation: Here is the explanation of the correct option = I2 RIf the current changes by 1% then new current will be:I/ = I x (1 - 1/100)=I x 0.99P/…
Correct answer: 2%- A. Electric flux
- B. Electric Potential
- C. Electric current
- D. Resistance
Explanation: The correct answer is Electric current. It is defined as the rate at which electric charge flows through a conductor.
Correct answer: Electric current- A. ammetre.
- B. voltmetre.
- C. ohmmetre.
- D. photometre.
Explanation: A) Ammeter: A galvanometer is a sensitive device that detects and measures small electric currents.
Correct answer: ammetre.- A. current.
- B. voltage.
- C. resistance.
- D. electric flux.
Explanation: Electric flux (option D) is a measure of the electric field passing through a given area.
Correct answer: electric flux.