Question

If two wires P and O each of the same length and same material,are connected in parallel to a battery. The diameter of P is half that of Q. What fraction of the total current passes through P?(a)0.2(b)0.25(c)0.33(d)0.5

Answer 1

The same current flows through the same cross-sectional area, but with only half the diameter, P has only ____ the area. Thus it passes ___ the current.

[If you halve the diameter what happens to the area?]

Answer 2

The answer is 0.20
use formula A = (pi*(d^2))/4
As resistivity and length are equal, they will cancel each other The ratio of resistance P to resistance Q will be 4.0.
I_p = V/R_p I_Q = V/R_Q
I_total = I_p + I_Q
dividing I_p by I , you will get 1/5 which is equal to 0.20