Answer:
a. 10 ohms.
Explanation:
Given;
first electrical resistance, r₁ = 20 ohms
let the first current through the circuit = I₁
let the second current through the circuit, I₂ = 2I₁ (since it is doubled)
then, the new value of the resistance after doubling the current = r₂
the current intensity is given as;
[tex]\frac{dI}{dt} = I = \frac{v}{r} \\\\I_1r_1 = I_2r_2\\\\r_2 = \frac{I_1r_1}{I_2} \\\\r_2 = \frac{I_1 \times 20}{2I_1 } \\\\r_2 = 10 \ ohms[/tex]
Therefore, the new value of the resistance is 10 ohms.