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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86 questions · page 5 of 5
- A. Thermistor
- B. Bulb filament
- C. Metals
- D. Semiconductors
Explanation: Ohm's law is valid for metallic conductors because they have a linear relationship between current and voltage.
Correct answer: Metals- A. Increase
- B. Decrease
- C. Not change
- D. None of these
Explanation: In a parallel circuit, the net resistance decreases as more components are added, because there are more paths for the current to pass…
Correct answer: Decrease- A. 2.5 times
- B. 5 times
- C. 10 times
- D. 30 times
Explanation: The Resistance of a wire is calculated asR = P L/Awhere R = resitance of the wireL = Length of the wireA is the area of the wire = (pi…
Correct answer: 2.5 times- A. 0.25 A
- B. 1.0 A
- C. 4.0 A
- D. 5.0 A
Explanation: Parallel Resistance is calculated by 1/Rt= (1/R1 + 1/R2 ...) hence Rt = 5Ohm. EMF is 20, and Ohm's Law, V=IR, determines I (current) as 4.0A
Correct answer: 4.0 A- A. Only the current is doubled
- B. Only the current is halved
- C. Only the resistance is doubled
- D. Only the resistance is halved
Explanation: The correct answer is that only the current is doubled. According to Ohm's law (V = IR), the current through a resistor is directly…
Correct answer: Only the current is doubled- A. r/2
- B. 4r
- C. 2r
- D. r/4
Explanation: When a wire is stretched to double its length, its resistance R changes according to the formula: [R' = 2R] So, the resistance of the wire…
Correct answer: 4r