Chapter 21, Problem 9MCQ

A window’s metal frame is essentially a metal loop through which a magnetic field can change when the window swings shut abruptly. The metal frame is $1.0\text{ m }\times 0.50\text{m}$ and Earth's $\text{5}\text{.0}\times {\text{10}}^{\text{-5}}\text{-T}$ magnetic field makes an angle of $53°$ relative to the horizontal. Which answer below is closest to the average induced emf when the window swings shut $90°$ in 0.20 s from initially parallel to the field? Assume that it's a vertical window that faces north when closed

a. $9.9\times {10}^{-1}\text{V}$

b. $\text{7}\text{.5}\times {\text{10}}^{\text{-5}}\text{V}$

C. $9.9\times {10}^{-2}\text{V}$

d. $12.5\times {10}^{-4}\text{V}$