Question

The figure shows three conductors I, II and III of same material, different lengths l, 2l and 3l and of different areas of cross-sections 3A, A and 2A respectively. Arrange them in the increasing order of current drawn from the battery.

पर्याय

• i₁ < i₂ < i₃

• i₃ < i₂ < i₁

• i₂ < i₁ < i₃

• i₂ < i₃ < i₁

Answer 1

i₂ < i₃ < i₁

Explanation:

As we know, resistance R = `ρ"l"/"A"`. The resistance of conductor l is given by

R_I = `ρ"l"/(3"A") = "R"/3` ...`("where R" = ρ"l"/"A")`

Similarly, R_II = `ρ(2"l")/"A"` = 2R

and R_III = `ρ(3"l")/(2"A") = 3/2"R"`

From this, we conclude that R_II >R_III > R_I. Since in parallel combination of resistances current distributes in the inverse ratio of resistances, therefore i₂ < i₃ < i₁.