Q1. What determines the resistance of a conductor?
a) Length and temperature
b) Length and diameter
c) Temperature and material
d) Material and diameter
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Correct Answer: b) Length and diameter
Explanation: The resistance of a conductor depends on its length and cross-sectional area (diameter), according to the formula R = ρ * (L/A), where ρ is the resistivity of the material.
Q2. Which material typically has the highest resistivity?
a) Copper
b) Silver
c) Aluminium
d) Nichrome
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Correct Answer: d) Nichrome
Explanation: Nichrome, an alloy of nickel and chromium, typically has higher resistivity compared to metals like copper, silver, and aluminium.
Q3. What happens to the resistance of a conductor as its temperature increases?
a) Increases
b) Decreases
c) Remains constant
d) Fluctuates randomly
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Correct Answer: a) Increases
Explanation: In general, the resistance of a conductor increases with temperature due to increased atomic vibrations, which hinder the flow of electrons.
Q4. What is the SI unit of resistance?
a) Volt
b) Ampere
c) Ohm
d) Watt
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Correct Answer: c) Ohm
Explanation: The SI unit of resistance is the Ohm (Ω), named after the German physicist Georg Simon Ohm.
Q5. Which of the following factors does not affect the resistance of a conductor?
a) Material
b) Temperature
c) Voltage
d) Length
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Correct Answer: c) Voltage
Explanation: Voltage does not directly affect the resistance of a conductor. Resistance is primarily influenced by the material, temperature, length, and cross-sectional area.
Q6. What happens to the resistance of a conductor as its cross-sectional area increases?
a) Increases
b) Decreases
c) Remains constant
d) Depends on the material
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Correct Answer: b) Decreases
Explanation: As the cross-sectional area of a conductor increases, there is more space for electrons to flow, reducing resistance according to the formula R = ρ * (L/A).
Q7. Which law states that the resistance of a conductor is directly proportional to its length and inversely proportional to its cross-sectional area?
a) Ohm’s Law
b) Faraday’s Law
c) Joule’s Law
d) The Law of Resistance
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Correct Answer: d) The Law of Resistance
Explanation: The Law of Resistance states that resistance (R) is directly proportional to length (L) and inversely proportional to cross-sectional area (A).
Q8. What is the resistance of a superconductor at low temperatures?
a) Very high
b) Very low
c) Zero
d) Variable
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Correct Answer: c) Zero
Explanation: Superconductors exhibit zero resistance at low temperatures, allowing for perfect conductivity without any energy loss.
Q9. Which of the following materials is commonly used as a resistor in electrical circuits?
a) Copper
b) Aluminium
c) Carbon
d) Silver
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Correct Answer: c) Carbon
Explanation: Carbon is commonly used in resistors due to its moderate resistivity and stability over a wide range of temperatures.
Q10. What is the effect of adding more resistors in series in an electrical circuit?
a) Increases total resistance
b) Decreases total resistance
c) No change in total resistance
d) Depends on the value of resistors
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Correct Answer: a) Increases total resistance
Explanation: In a series circuit, the total resistance is the sum of individual resistances. Therefore, adding more resistors in series increases the total resistance of the circuit.