While performing an experiment, a student reduces the resistance to one half keeping the potential difference same. New reading of the current will be :

1. half
2. double
3. four times
4. one fourth

double

Reason — Let initial and final current be I and I_new, initial and final resistance is R and R_new and initial and final potential be V and V_new

From Ohm's law,

Case 1 :

$\text V = \text {IR}$

Case 2 :

$\text V${\text {new}} = \text I{\text {new}}\text R_{\text {new}}

According to question,

$\text V${\text {new}}=\text V\ \text { and}\ \text { R}{\text {new}}=\dfrac {1}{2}\text R\\[1 em] \Rightarrow \text I{\text {new}}\text R{\text {new}} = \text {IR} \\[1 em] \Rightarrow \text I{\text {new}}\times \dfrac{1}{2}\text R = \text {IR} \\[1 em] \Rightarrow \dfrac{\text I{\text {new}}}{2} = \text I \\[1 em] \Rightarrow \text I_{\text {new}} = 2\text I