JEE PYQ: Magnetic Effects Of Current Question 17
Question 17 - 2020 (04 Sep 2020 Shift 1)
A wire $A$, bent in the shape of an arc of a circle, carrying a current of $2$ A and having radius $2$ cm and another wire $B$, also bent in the shape of arc of a circle, carrying a current of $3$ A and having radius of $4$ cm, are placed as shown in the figure. The ratio of the magnetic fields due to the wires $A$ and $B$ at the common centre $O$ is:
(1) $4:6$
(2) $6:4$
(3) $2:5$
(4) $6:5$
Show Answer
Answer: (4) $6:5$
Solution
$\frac{B_A}{B_B} = \frac{I_A}{I_B} \times \frac{\theta_A}{\theta_B} \times \frac{R_B}{R_A} = \frac{2}{3} \times \frac{3\pi/2}{5\pi/3} \times \frac{4}{2} = \frac{6}{5}$.
BETA
