Question

A solenoid has a length L = 1.23m and an inner diameter d = 3.55cm. It has five layers of windings of 850 turns each and carries a current $i_{0} = 5.57A$. What is B at its center?

• A. $5mT$
• B. $30.8mT$
• C. $43.2mT$
• D. $24.2mT$

Answer 1

Answer: (D)

$24.2mT$

Answer 2

From the equation $B = \mu_{0}i_{0}n$ =

$\left( 4\pi \times 10^{- 7}T.m/A \right)(5.57A)\left( \frac{5 \times 850turns}{1.23m} \right)$

=$2.42 \times 10^{- 2}T = 24.2mT$