Two uniform wires A and B are of the same metal and have equal masses. The radius of wire A is twice that of wire B. The total resistance of A and B when connected in parallel is
Text Solution
Verified by ExpertsA
Density and masses of wire are same so their volumes are same i.e. $A_1 I_1 = A_2 I_2$
Ratio of resistances of wires A and $\mathrm{B} \frac{R_A}{R_B}$
$= \frac{l_1}{l_2} \times \frac{A_2}{A_1} = \left(\frac{A_2}{A_1}\right)^2 = \left(\frac{r_2}{r_1}\right)^4$ Since $r_1 = 2r_2$ so $\frac{R_A}{R_B} = \frac{1}{16}$
$\Rightarrow R_{B} = 16 R_{A}$
Resistance RA and RB are connected in parallel so equivalent resistance $R = R_A R_B / R_A + R_B = 16 R_A / 17$ By checking correctness of equivalent resistance from options, only option is correct.
Prepare Smarter with CGP Edu
Get practice questions, solutions, and test series in one place.
Write a Review
Share your experience with this question and solution.
Commentary
Send your comment, doubt, correction, or feedback to admin.
Similar Questions
Explore conceptually related problems