Free Resistance and Resistivity MCQs with Answers
86 Resistance and Resistivity MCQs from Physics, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
Resistance measures opposition to current in a conductor and follows R = V/I for an ohmic conductor, while resistivity is an intrinsic property of the material. Questions use R = ρL/A, examine effects of length, cross-sectional area and temperature, and distinguish resistance, resistivity, conductance and conductivity.
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- 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. Compare resistances
- B. Determine the current
- C. Determine the charge
- D. Determine the e.m.f
Explanation: The Wheatstone bridge is used for the precise measurement of low resistance.
Correct answer: Compare resistances- A. 10-8 Ωm
- B. 10-10 Ωm
- C. 10-6 Ωm
- D. 102 Ωm
Explanation: a) 10^-8 Ωm:This option suggests a resistivity value of 10^-8 Ωm for copper.
Correct answer: 10-8 Ωm- A. 1 Farad
- B. 10 coulomb
- C. 1 coulomb
- D. 10 ohm
- E. 1 ohm
Explanation: The explanation for this question will be added soon.
Correct answer: 10 ohm- A. 4R
- B. R/4
- C. 8R
- D. 16R
Explanation: If you stretch the wire till its radius is halved the previous value, then its length will increase 4 times to keep the volume constant.
Correct answer: 16R- A. Double
- B. One Forth
- C. One half
- D. 4 times
Explanation: Resistance (R) is directly proportional to the length (L) and inversely proportional to the cross-sectional area (A) of the wire.
Correct answer: 4 times- A. 1 x 10^-7
- B. 2.63 x 10^-8
- C. 19 x 10^-8
- D. 7.85 x 10^-8
Explanation: he resistivity (ρ) of a wire can be calculated using the formula:ρ = (R * A) / Lwhere R is the resistance, A is the cross-sectional area…
Correct answer: 1 x 10^-7