A long solenoid has 1000 turns per meter and its radius is R=2.5 cm. Current in the solenoid increases at a rate of 200π A/s. Find the magnitude of induced electric field at a point outside the solenoid at a distance 4 cm from its axis.
The correct option is B 6.25×10−4 V/m
The induced electric field is obtained from expression:
At point B at distance r from centre of solenoid (outside it),
⇒since induced electric field is tangetial along circumference (θ=0∘), and area direction along →B hence angle between B & S i.e θ=0∘
Now, for solenoid
putting the values,
From Eq (ii),