An electric circuit is consisting of a cell, an ammeter and a nichrome

An electric circuit is consisting of a cell, an ammeter and a nichrome wire of length l. If the length of the wire is reduced to half (l/2), then the ammeter reading

[amp_mcq option1=”decreases to one-half.” option2=”gets doubled.” option3=”decreases to one-third.” option4=”remains unchanged.” correct=”option2″]

This question was previously asked in

UPSC CDS-2 – 2021

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According to Ohm’s law, the current (I) through a circuit is inversely proportional to the resistance (R), assuming the voltage (V) is constant (from the cell). The resistance of a wire is directly proportional to its length (R ∝ l). If the length of the nichrome wire is reduced to half (l/2), its resistance becomes half (R/2). Therefore, the current (I = V/R) will double (I’ = V/(R/2) = 2V/R = 2I). The ammeter reading, which measures the current, will get doubled.

Resistance is directly proportional to length. Current is inversely proportional to resistance.

This assumes the temperature of the wire and other factors remain constant. Nichrome is used as a resistive wire material.

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