Question

A flat coil of wire has an area of 0.020 m2 and contains 50 turns. Initially the coil is oriented so that the normal to its surface is parallel to and in the same direction as a constant magnetic field of 0.18 T. The coil is then rotated through an angle of 30o in a time of 0.10 s. What is the average induced emf? -0.44 V +0.44 V +0.24 V

Answer 1

3rd option: +0.24 V

Explanation:

Given:

N = 50

Area = 0.020 m^2

B = 0.18 T

θf = 30°

time = 0.10 s

We can calculate the average induced emf by the following formula

`\epsilon=N\cdot B\cdot A\cdot\left((\cos\theta_i-\cos\theta_f)/(t)\right)`

We replacing:

`\begin{gathered} \epsilon=\left(50\right)\left(0.18\right)\left(0.02\right)\left((\cos\:0\degree\:-\cos\:30\degree)/(\:0.1)\right) \\ \epsilon=0.241\cong0.24\text{ V} \end{gathered}`

The correct answer is 0.24V