$($a$)$ State and briefly explain the factors that determine the output power from wind energy. $(5)$

$($b$)$ What is Betz limit$?$ What is its importance? $(3)$

$($c$)$ Compare the horizontal$-$axis wind turbine $($HAWT$)$ and the vertical$-$axis wind turbine $($VAWT$).(6)$

$($d$)$ Define tip speed ratio and state why it is regarded as a very important parameter of a wind turbine.