b for this purpose is an approximation good to

one percent when this fractional energy loss itself is

less than two percent.M $($kilograms$)$ or M$^(*)($meters$)=$

G$($M$)/($c$^(2))$ and radius r$.$ From the fractional energy loss,

show that the fractional change of frequency is given

by the expression

$(\backslash$Delta f$)/($f$)=-($M$^(*))/($r$),[$escape field of spherical object$]$

This decrease in frequency is called the gravitational

red shift because, for visible light, the shift is toward

the lower$-$frequency $($red$)$ end of the visible spectrum.