Question

A student builds a simple circuit with a single resistor with resistance R and measures an electric potential difference ΔV across the resistor. Then, the student replaces the resistor with a new one of resistance 2R and keeps the electric potential difference the same. What is the current (I2) through the new circuit in terms of the original current​(I1)? 

Answer 1

$\Delta V_1=I_1R,$

$\Delta V_2=I_2\cdot 2R.$

If $\Delta V_1=\Delta V_2:$

$I_1R=I_2\cdot 2R,$

$I_2=I_1/2.$

Answer: $I_2=I_1/2.$