The magnetic field, of a given length of wire for single turn coil, at its center is ' B ' . then its value…

The magnetic field, of a given length of wire for single turn coil, at its center is 'B'. then its value for two turns coil for the same wire is
  1. B4
  2. B2
  3. 4B
  4. 2B

Solution

Magnetic field, B=μnia

After turning the coils into 2 turns, n'=2n, a'=a2

⇒B∝na

⇒B'B=n'n×aa'

⇒B'B=2nn×2aa

⇒B'B=4

⇒B'=4B

Asked in: AP EAMCET 2021 (19 Aug Shift 2)

Practice more Magnetic Fields due to Electric Current questions on Aicharya