There are two wires of the same metal of same area of cross section but having lengths in the ratio 2 : I. If same p.d. is applied across their ends, what will be the ratio of current in them?

Options

A. 1
B. 2
C. 3
D. 4

Answer

A

Explanation

`i_1r_1=1_2r_2 but therefore V=IR therefore (V_1)/V_2=(1_1R_1)/(1_2R_2)` But `R propto l`(assume that they have the same p and A) `therefore (R_1)/R_2=l_1/l_2=(2pir_1)/(2pir_2)=r_1/r_2=2/1 therefore From (1) and (2), V_1/V_2=(i_1/i_2)(R_1/R_2)=1/2 xx 2/1 =1`.