What should be the angle of incidence for a ray of light which suffers minimum deviation of 36° through an equilateral prism?[ Hint — A = 60° and i = ( A + δ_min ) / 2 ]

An object when placed in a denser medium and is viewed from a rarer medium appears to be at a lesser depth than real death. This is because of :

1. reflection
2. refraction
3. dispersion
4. diffraction

A small air bubble in a glass block when seen from above appears to be raised because of:

1. refraction of light
2. reflection of light
3. reflection and refraction of light
4. none of the above

An object in a denser medium when viewed from a rarer medium appears to be raised. The shift is maximum for:

1. red light
2. violet light
3. yellow light
4. green light