Moving Charges and Magnetism - Result Question 30
31. Two toroids 1 and 2 have total no. of turns 200 and 100 respectively with average radii $40 cm$ and $20 cm$ respectively. If they carry same current $i$, the ratio of the magnetic fields along the two loops is,
(a) $1: 2$
(b) $1: 1$
(c) $4: 1$
(d) $2: 1$
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Answer:
Correct Answer: 31. (b)
Solution:
(b) $B=\frac{\mu_0 N \cdot I}{2 \pi R}$
$\therefore \quad \frac{B_1}{B_2}=\frac{N_1 R_2}{N_2 R_1}=\frac{200}{100} \frac{20}{40}=1$
So, $\frac{B_1}{B_2}=1$
