In the circuit shown below, the key K is closed at t = 0. The cu

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 Multiple Choice QuestionsMultiple Choice Questions

11.

The resistance of a given wire is obtained by measuring the current flowing in it and the voltage difference applied across it. If the percentage errors in the measurement of the current and the voltage difference are 3% each, then error in the value of resistance of the wire is

  • 6%

  • zero

  • 1%

  • 1%

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12.

Two electric bulbs marked 25W – 220V and 100W – 220V are connected in series to a 440Vsupply. Which of the bulbs will fuse?

  • Both

  • 100 W

  • 25 W

  • 25 W

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13.

If a wire is stretched to make it 0.1% longer, its resistance will

  • increase by 0.2%

  • decreases by 0.2%

  • decrease by 0.05 %

  • decrease by 0.05 %

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14.

A rectangular loop has a sliding connector PQ of length

  • straight I subscript 1 space equals space straight I subscript 2 space space equals space fraction numerator straight B space calligraphic l straight v over denominator 6 straight R end fraction comma space fraction numerator straight B space calligraphic l straight v over denominator 3 straight R end fraction
  • straight I subscript 1 space equals space minus straight I subscript 2 space equals space fraction numerator straight B space calligraphic l straight v over denominator straight R end fraction comma space straight I space equals fraction numerator 2 straight B space calligraphic l straight v over denominator 3 straight R end fraction
  • straight I subscript 1 space equals space straight I subscript 2 space space equals space fraction numerator straight B space calligraphic l straight v over denominator 3 straight R end fraction comma space straight I space equals space fraction numerator 2 straight B space calligraphic l straight v over denominator 3 straight R end fraction
  • straight I subscript 1 space equals space straight I subscript 2 space space equals space fraction numerator straight B space calligraphic l straight v over denominator 3 straight R end fraction comma space straight I space equals space fraction numerator 2 straight B space calligraphic l straight v over denominator 3 straight R end fraction
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15.

In the circuit shown below, the key K is closed at t = 0. The current through the battery is

  • fraction numerator VR subscript 1 straight R subscript 2 over denominator square root of straight R subscript 1 superscript 2 plus straight R subscript 2 superscript 2 end root end fraction space at space straight t space equals space 0 space and space straight V over straight R subscript 2 space at space straight t space equals space infinity
  • straight V over straight R subscript 2 space at space straight t space equals space 0 space and space fraction numerator straight V left parenthesis straight R subscript 1 plus straight R subscript 2 right parenthesis over denominator straight R subscript 1 straight R subscript 2 end fraction space at space equals space infinity
  • straight V over straight R subscript 2 space at space straight t space equals space 0 space and space fraction numerator VR subscript 1 straight R subscript 2 over denominator square root of straight R subscript 1 superscript 2 space plus space straight R subscript 2 superscript 2 end root end fraction space at space straight t space equals space infinity
  • straight V over straight R subscript 2 space at space straight t space equals space 0 space and space fraction numerator VR subscript 1 straight R subscript 2 over denominator square root of straight R subscript 1 superscript 2 space plus space straight R subscript 2 superscript 2 end root end fraction space at space straight t space equals space infinity


B.

straight V over straight R subscript 2 space at space straight t space equals space 0 space and space fraction numerator straight V left parenthesis straight R subscript 1 plus straight R subscript 2 right parenthesis over denominator straight R subscript 1 straight R subscript 2 end fraction space at space equals space infinity

At t = 0, inductor behaves like an infinite resistance so , at t = 0,
i = V/R2
and at t = ∞, inductor behaves like a conducting wire i.e., resistance less wire
then, 

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16.

Which of the following statements is false?

  • A rheostat can be used as a potential divider

  • Kirchhoff's second law represents energy conservation

  • Wheatstone bridge is the most sensitive when all the four resistances are of the same order of magnitude.

  • Wheatstone bridge is the most sensitive when all the four resistances are of the same order of magnitude.

398 Views

17.

When a current of 5 mA is passed through a galvanometer having a coil of resistance 15Ω, it shows full-scale deflection. The value of the resistance to be put in series with the galvanometer to convert it into to voltmeter of range 0 – 10 V is

  • 2.535 × 103 Ω

  • 4.005 × 103 Ω

  • 1.985 × 103 Ω

  • 1.985 × 103 Ω

326 Views

18.

In the above circuit the current in each resistance is

  • 0.5 A

  • 0 A

  • 0.25

  • 0.25

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19.

This question contains Statement-1 and Statement-2. Of the four choices given after the statements,choose the one that best describes the two statements.

Statement-1: The temperature dependence of resistance is usually given as R = Ro(1 + α∆t). The resistance of a wire changes from 100 Ω to 150 Ω when its temperature is increased from 27o C to 227o C. This implies that 3o 2.5 10 / C − α= ×.
Statement 2: R = Ri(1 + α∆T) is valid only when the change in the temperature ∆T is small and ∆R =(R - Ro) << Ro.

  • Statement-1 is true, Statement-2 is false.

  • Statement-1 is true, Statement-2 is true; Statement-2 is the correct explanation of Statement-1.

  • Statement-1 is true, Statement-2 is true; Statement-2 is not the correct explanation of Statement-1.

  • Statement-1 is true, Statement-2 is true; Statement-2 is not the correct explanation of Statement-1.

207 Views

20.

Shown in the figure below is a meter-bridge set up with null deflection in the galvanometer.

The value of the unknown resistor R is

  • 13.75 Ω

  • 220 Ω

  • 110 Ω

  • 110 Ω

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