In an ammeter, 0.25 % of main current passes through the galvanometer. If the resistance of the galvanometer is ' G ', the resistance of ammeter will be

Step-by-step solution

aligned & I = I _ g + I _ s & I = 0.25 I 100 + I _ s & I _ s = 399 400 I ...(i) & I _ g G = I _ s ~S & ~S = 0.25 100 400 399 G & ~S = 1 399 G ...(ii) aligned ...[From (i)] Total resistance of ammeter aligned R & = G S G+S & = G ( 1 399 )G (G+ 1 399 ) G & = 1 ( 399 400 ) 399 G R & = 1 400 G aligned ...[From (ii)]