A galvanometer having a resistance of 8 is shunted by a wire of resistance 2 . If the total current is 1 ~A , the part of it passing through the shunt will be

Step-by-step solution

Let total current through the parallel combination be I , the current through the galvanometer be I_g and the current through the shunt be I-I_g . The shunted galvanometer is shown in the figure. The potential difference, V_ a b = (V_a-V_b ) is the same for both paths, so I_g G= (I-I_g ) S I_g(G+S)=I S I_g I = S S+G The fraction of current passing through shunt aligned & = I-I_g I =1- I_g I =1- S S+G = G S+G & = 8 2+8 = 8 10 =0.8 ~A aligned