MCQ On Relation Between Resistance And Length

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Jasmine Grover

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The relation between length and resistivity is given by the resistivity formula ρ = RA/l. Resistance is directly proportional to the length which means that any change in the length of the material will directly change its value of resistance. Relation between Resistance and Length MCQs are given as below.

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Ques. What is the formula for resistivity? 

  1. ρ = RI/A
  2. ρ = A/lR
  3. ρ = RA/l
  4. ρ = R/lA

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Ans. c. ρ = RA/l

Explanation: ρ, is quantitatively equal to the resistance R of a specimen such as a wire, multiplied by its cross-sectional area A, and divided by its length l; ρ = RA/l. 

Ques. What has the highest resistivity? 

  1. Tungsten
  2. Nichrome
  3. Carbon
  4. Nirosta

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Ans. b. Nichrome

Explanation: Nichrome has the highest resistivity and shows the heating effect of electric current because of its high resistance

Ques. What is the resistivity of copper wire? 

  1. 1.72 x 10-8 Ωm
  2. 1.72 x 10+8 Ωm
  3. 1.71 x 10-8 Ωm
  4. 1.71 x 10+8 Ωm

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Ans. a. 1.72 x 10-8 Ωm

Explanation: The resistivity of a particular material is measured in units of Ohm-Metres (Ωm) which is also affected by temperature.

Ques. Resistance can be described as the 

  1. opposition to voltage flow
  2. resist rate of the voltage
  3. opposition to current flow
  4. current acceptability of a voltage

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Ans. c. opposition to voltage flow

Explanation: Resistance can be described as the opposition to voltage flow

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Ques. The resistance of a material is commonly affected by four factors-length, cross-sectional area, type of material and 

  1. current
  2. voltage
  3. type of supply
  4. temperature

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Ans. d. temperature

Explanation: Resistance of a material is commonly affected by four factors-length, cross-sectional area, type of material and temperature

Ques. Resistivity depends on the factors

  1. Nature and the temperature of the conductor
  2. Nature, shape and the temperature of the conductor
  3. Nature, shape, size and the temperature of the conductor 

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Ans. a. Nature and the temperature of the conductor

Explanation: The resistivity of a material depends on its nature and the temperature of the conductor, but not on its shape and size.

Ques. In the formula R= ρI/A, the symbol ρ stands for the

  1. cross-sectional area of the conductor in m2
  2. product of the length of the conductor in meters
  3. resistivity of the material on ohm-meters
  4. resistance of the conductor ohms per meter

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Ans. c. resistivity of the material on ohm-meters

Explanation: In the formula R= ρI/A, the symbol ρ stands for the resistivity of the material on ohm-meters.

Ques. The temperature coefficient of resistance of a material is defined as the change in 

  1. resistance per ohm per degree Celsius
  2. temperature per degree per ohm
  3. length per meter per ohm resistance
  4. cross-sectional area per meter per degree Celsius

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Ans. a. resistance per ohm per degree celsius

Explanation: The temperature coefficient of resistance of a material is defined as the change in resistance per ohm per degree celsius

Ques. Which metal has the lowest resistance?

  1. Gold
  2. Diamond
  3. Silver
  4. Platinum

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Ans. c) Silver

Explanation: Element silver has the lowest resistivity and hence has higher conductivity

Ques. The resistivity of a material is defined as the: 

  1. amount of opposition to a flow of resistance through a 1-meter cube of the material
  2. the resistance between the opposite faces of a 1-meter cube at a specified temperature
  3. resistance of 100 meters of 1.5 mm2 copper cable at a specified temperature
  4. the resistance between two faces of a 1 mm2 block of that material at 20 °C

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Ans. b. the resistance between the opposite faces of a 1-meter cube at a specified temperature

Explanation: The resistivity of a material is defined as the resistance between the opposite faces of a 1-meter cube at a specified temperature.

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