In the circuit shown in the given figure, for R = 20 Ω,

In the circuit shown in the given figure, for R = 20 Ω, the current I is 2 A. When R is 10 Ω, then current I would be

When I = 2 amp, then V_N2 = 20 (4 – I) = 40 volts.
When R = 10 Ω , then V_N2 remains unchanged.

and I = 4 -		V_N2		= 4 - 2 = 2 amp.
		20