Paraxial Approximation

Q. Which of the following statements are true regarding paraxial approximation?

1. The rays coming to the mirror must be parallel to the principal axis of the mirror
2. The rays falling on the spherical mirror must be extremely close to the principal axis of the mirror
3. Only the rays parallel to the principal axis of the spherical mirror should be used to draw the ray diagram
4. all of the above.

Q. Which of the following (referred to a spherical mirror) do (does) not depend on whether the rays are paraxial or not?

1. Pole
2. Focus
3. Radius of curvature
4. Principal axis.

Q. Since sun is faraway from the earth, the sun rays can be assumed parallel when they reach the earth surface.

1. True
2. False

Q. In image formation from spherical mirrors, only paraxial rays are considered because they

1. are easy to handle geometrically
2. are not parallel to principal axis
3. form nearly a point image of a point source
4. are far from principal axis

Q. In image formation from spherical mirrors, only paraxial rays are considered because they
(a) are easy to handle geometrically
(b) contain most of the intensity of the incident light
(c) from nearly a point image of a point source
(d) show minimum dispersion effect.