Question:
A wire of resistance R is elongated n-fold to make a new uniform wire. The resistance of new wire
A wire of resistance R is elongated n-fold to make a new uniform wire. The resistance of new wire
Updated On: Jul 6, 2022
- nR
- $n^2R$
- 2nR
- $2n^2R$
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The Correct Option is B
Solution and Explanation
The resistance of a wire is directly proportional to the length of the wire.
Thus, $R ??$, so the length increases n-fold also since the volume of the wire remains constant, so the area of the wire
decreases n-fold.
Hence the resistance increases to $n^2R$ as the area is inversely proportional to resistance.
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Concepts Used:
Electromagnetic Induction
Electromagnetic Induction is a current produced by the voltage production due to a changing magnetic field. This happens in one of the two conditions:-
- When we place the conductor in a changing magnetic field.
- When the conductor constantly moves in a stationary field.
Formula:
The electromagnetic induction is mathematically represented as:-
e=N × d∅.dt
Where
- e = induced voltage
- N = number of turns in the coil
- Φ = Magnetic flux (This is the amount of magnetic field present on the surface)
- t = time
Applications of Electromagnetic Induction
- Electromagnetic induction in AC generator
- Electrical Transformers
- Magnetic Flow Meter