Question

A coil had 100 turns. The radius of each turn is
20 cm. An iron rod (u = 35) is introduced inside
it. Find the magnetic field at the centre when current
in coil is 2 A.
(1) 0.022 T
(2) 0.22 T
(3) 0.33 T
(4) 0.033 T​

Answer 1

Answer:

n=100, r = 20 cm = 0.2 m, μr=

μ

0

μ

=35

i=2A

⇒μ=35μ

0

μ=35×4π×10

−7

m k.s unit

Field at certen will

be B=

2r

μi

×m

B=

2×0.2

35×4π×10

−7

×2×100

⇒B=.0219≈.022 Tesla

m.k.s unit.