Current Electricity

Current Electricity

Easy Questions

Electricity and Magnetism

Current Electricity
Moving Charges and Magnetism
Magnetism and Matter
Electromagnetic Induction
Alternating Current
Electromagnetic Waves
  1. ​What will be the equivalent resistance of circuit shown in figure between two points A and D









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    = 10 Ω +20 × 20+ 10 = 10 + 10 + 10 = 30 Ω
    20 + 20

    Correct Option: C


    = 10 Ω +20 × 20+ 10 = 10 + 10 + 10 = 30 Ω
    20 + 20

  1. ​The resistivity (specific resistance) of a copper wire​​








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    Resistivity of copper wire increases with increase in temprature as ρt = ρ0(1 + αt)
    Copper being a metal has positive coefficient of resistivity.

    Correct Option: A

    Resistivity of copper wire increases with increase in temprature as ρt = ρ0(1 + αt)
    Copper being a metal has positive coefficient of resistivity.

  1. Si and Cu are cooled to a temperature of 300 K, then resistivity?​​








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    Conductivity of semiconductor increases with increase in temperature while conductivity of metal decreases with increase in temperature.

    Correct Option: B

    Conductivity of semiconductor increases with increase in temperature while conductivity of metal decreases with increase in temperature.

  1. A wire has a resistance of 3.1Ω at 30ºC and a resistance 4.5Ω at 100ºC. The temperature coefficient of resistance of the wire​​








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    R1 = 3.1 Ω at t = 30°C ​
    R2 = 4.5 Ω at t = 100°C ​
    We have,   R = R0 (1 + αt) ​
    ∴ R1 = R0 [1 + α (30)] ​
    R2 = R0 [1 + α (100)]

    ⇒R1=1 + 30α
    R21 + 100α

    ⇒3.1=1 + 30α⇒ α = 0.0064 °C-1
    4.51 + 100α

    Correct Option: A

    R1 = 3.1 Ω at t = 30°C ​
    R2 = 4.5 Ω at t = 100°C ​
    We have,   R = R0 (1 + αt) ​
    ∴ R1 = R0 [1 + α (30)] ​
    R2 = R0 [1 + α (100)]

    ⇒R1=1 + 30α
    R21 + 100α

    ⇒3.1=1 + 30α⇒ α = 0.0064 °C-1
    4.51 + 100α

  1. A 6 volt battery is connected to the terminals of the three metre long wire of uniform thickness and resistance of 100 ohm. The difference of potential between two points on the wire separated by a distance of 50 cm will be​​








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    ​R α l ​
    For 300 cm, R = 100 Ω

    For 50 cm, R' -
    100
    		× 50 =
    50
    		Ω
    3003

    ∴ IR = 6
    ⇒ IR' =6 × R' = 6 × 50 = 1 volt.
    R1003

    Correct Option: D

    ​R α l ​
    For 300 cm, R = 100 Ω

    For 50 cm, R' -
    100
    		× 50 =
    50
    		Ω
    3003

    ∴ IR = 6
    ⇒ IR' =6 × R' = 6 × 50 = 1 volt.
    R1003