
Assertion: An air bubble in a jar of water shines brightly due to the phenomenon of total internal reflection.
Reason: Refraction of light is the phenomenon of change in the path of light when it goes from one medium to another.


Important Questions on Ray Optics
Assertion : For observing traffic at our back, we prefer to use a convex mirror.
Reason : A convex mirror has a much larger field of view than a plane mirror or concave mirror.

Assertion: Critical angle of light passing from glass to air is minimum for violet colour.
Reason: The wavelength of violet light is greater than the light of other colours.

Assertion: A concave mirror of some focal length in air is used in a medium of refractive index Then the focal length of the mirror in that medium will remain the same.
Reason: The focal length of a mirror is half of the radius of curvature of the mirror.

Assertion: We cannot produce a real image by plane or convex mirrors under any circumstances.
Reason: The focal length of a convex mirror is always taken as positive.

Reason: In reflection, angle of incidence is always equal to angle of reflection.

Assertion: The frequencies of incident, reflected and refracted beam of monochromatic light incident from one medium to another are same.
Reason: The incident, reflected and refracted rays are coplanar.

Assertion: A convex lens of glass behave as a diverging lens when immersed in carbon disulphide of higher refractive index .
Reason: A convex lens is thinner in the middle and thicker at the edges.

Assertion: The twinkling of stars is due to the refraction of light.
Reason: The velocity of light changes while going from one medium to the other.
