What is used to measure doppler line broadening.
Polaroid
Diffration grating
Herapathite
Plasma
The angle of incidence at which reflected light is totally polarized form aim is :
$\sin ^ { - 1 } ( n )$
$\sin ^ { - 1 } \left( \frac { 1 } { n } \right)$
$\tan ^ { - 1 } \left( \frac { 1 } { n } \right)$
$\tan ^ { - 1 } ( n )$