Light is incident normally on a small plane surface. If the surface is rotated by an angle of 300 about the incident light, does the illuminance of the surface increase, decrease or remain same ? Does your answer change if the light did not fall normally on the surface ?

Unpolarised light is incident from air on a plane surface of a material of refractive index u! At a particular angle of incidence mu it is found that the reflected and refracted rays are perpendicular to each other. Which of the following options is correct for this situation ?

A plane polarized light is incident normally on a tourmaline plate. Its vecE vectors make an angle of 60^(@) with the optic axis of the plate. Find the percentage difference between initial and final intensities.

A laser beam of power 20W incident normally on a surface. if 25% light is absorbed and rest reflected find magnitude of force experienced by the surface.

Unpolarised light is incident on a plane glass surface. What would be the angle of incidence so that the reflected and refracted rays are perpendicular to each other.

A ray of light is incident normally on the first refracting face of the prism of refracting angle A. The ray of light comes out at grazing emergences. If one half of the prism (shaded position) is knocked off, the same ray will:-

A ray R_(1) is incident on the plane surface of the glass slab (kept in air) of refractive index sqrt(2) at angle of incident equal to the critical angle for this air glass system. The refracted ray R_(2) undergoes partial reflection & refraction at the other surface. The angle between the reflected ray R_(3) and the refracted ray R_(4) at that surface is :

A beam of light from a source L is incident normally on a plane mirror fixed at a certain distance x from the source. The beam is reflected back as a spot on a scale placed just above the source L. When the mirror is rotated through a small angle theta , the spot of the light is found to move through a distance y on the scale. The angle theta is given by

Light with an energy flux of 18 W//cm^(2) falls on a nonreflecting surface at normal incidence. If the surface has an area of 20 cm^(2) , find the average force exerted on the surface during a 30 minute time span.