NEET-XII-Physics
neet 2020 questions with solutions year:2020
- #37A long solenoid of `` 50\,cm `` length having `` 100\,turns `` carries a current of `` 2.5\,A `` . The magnetic field at the centre of the solenoid is :
`` (\mu_o = 4\pi \times 10^{-7} T\,m\,A^{-1}) ``
(A) `` 6.28 \times 10^{-4}T ``
(B) `` 3.14 \times 10^{-4}T ``
(C) `` 6.28 \times 10^{-5}T ``
(D) `` 3.14 \times 10^{-5}T ``
digAnsr: AAns : Magnetic field at centre of solenoid `` =\mu_{0}nI ``
`` n=\frac{N}{L} ``
`` =\frac{100}{50 \times 10^{-2}} ``
`` =200 `` tums/m
`` I = 2.5 \,A ``
On putting the values,
`` B=4\pi\times 10^{-7}\times 200 \times 2.5 ``
`` =6.28 \times 10^{-4}\,T ``