Can someone explain me how to do this question? Thanks.

1 Answer
Feb 25, 2018

#A.#

Explanation:

When,two resistors are connected in series,current flowing through them is the same.

Now,when #X# and #Y# are connected in series,if #2A# current is flowing through them,so from the graph, when #I = 2A#, for #X# ,Voltage = #4V#,so its resistance = #4/2=2 Omega#,

And,for #Y# at #I=2# #V=10#

So,total voltage of the circuit is #4+10=14V#

if the resistance of #Y# is #r#, then we can say, #14/(2+r) = 2#

so, #r=5 Omega#

So,total resistance of combination is #2+5=7 Omega#