Magnetic Effects Of Current Question 12
Question 12 - 29 January - Shift 2
The electric current in a circular coil of four turns produces a magnetic induction $32 T$ at its centre.
The coil is unwound and is rewound into a circular coil of single turn, the magnetic induction at the centre of the coil by the same current will be :
(1) $8 T$
(2) $4 T$
(3) $2 T$
(4) $16 T$
Show Answer
Answer: (3)
Solution:
Formula: Magnetic field due to circular loop
$B=\frac{\mu_0 1}{2 R} \times 4$
$B^{\prime}=\frac{\mu_0 i}{2 R^{\prime}}$
$R^{\prime}=4 R$
$B^{\prime}=\frac{\mu_0 i}{8 R}$
$\frac{B^{\prime}}{B}=\frac{1}{16}$
$B^{\prime}=2 T$
