Answer:
R = ½ R₀
Step-by-step explanation:
This is an exercise in Ohm's law,
V = IR
in the initial case
V₀ = I₀ R₀ (1)
indicates that the voltage remains constant and the current is doubled
I = 2 I₀
V₀ = I R
we substitute
V₀ = 2 I₀ R
R = ½ V₀ / I₀
we replace by equation 1
R = ½ R₀