Why is the red colour selected for danger signal lights?

Explain with a diagram why the sky appears blue.

Whether a concave lens is called a converging or diverging lens? Answer with reason.

Write Snell's law of refraction of light. OR Write two characteristics of the image of an extended object formed when it is placed in between the optical centre and focus of a thin convex lens.

What is meant by the principal axis of a concave lens?

Determine the angle of deviation for the refraction of light rays from rarer to denser medium. [2] (angle of incidence = i, angle of refraction = r) OR Why do the green leaves of trees appear 'green' in sunlight? [2]

What type of lens is used as a magnifying glass?

What is Hypermetropia? Which type of lens is used to rectify it? [2+1]

For which value of the angle of incidence in refraction of light is Snell's law not applicable?

Which type of mirror produces a virtual, diminished and erect image? (a) Plane mirror (b) Concave mirror (c) Convex mirror (d) Parabolic mirror

Determine the speed of a light ray passing through a glass slab of refractive index 1.5. [c = 3 × 10⁵ m s⁻¹]

Define dispersion of light. How would you identify monochromatic light and composite light with the help of a prism? [1 + 2]