Answer
a. $1.44\times10^{-5}Wb$, 0.
b. 0.36mV.
Work Step by Step
a. $\Phi_{B,i}=BAcos0^{\circ}=(6.0\times10^{-5}T)(12\times10^{-4}m^2)(1)=7.2\times10^{-8}Wb$
The total flux is $N \Phi_{B,i}=(200)( 7.2\times10^{-8}Wb)=1.44\times10^{-5}Wb $
Afterward the flux is zero.
$\Phi_{B,f}=BAcos90^{\circ}=0Wb $
b. $|\epsilon|= |\frac{\Delta \Phi_{B} }{\Delta t}|$
$$|\epsilon|= |\frac{\Phi_{B,f}-\Phi_{B,i}}{\Delta t}|$$
$$|\epsilon|= |\frac{0-1.44\times10^{-5}Wb }{0.040s}|=0.36mV$$