name a point inside a lens through which a ray of light goes undeviated?

Question

1) name a point inside a lens through which a ray of light goes undeviated
2) a 1 cm high object is placed at a dist. of 2f from a convex lens. What is the height of the image formed.
3) A convex lens_____ a parallel beam of light while concave lens _____ a parallel beam of light.
4) give one condition when there is no refraction of light even when it passes from one medium to another.
5) name the muscle which controls the focal length of the eye lens.

Answer 1

1) its optical centre
2) 1/2 cm
3)converges, diverges
4)perpendicular incidence of light
5)ciliary muscles

Answer 2

1. I forget its name, but it's the middle of the simple lens.
2. You get this from 1/f = 1/s1 + 1/s2 where s1 and s2 are the object and image distances. Work it out knowing that s1 = 2f. Hint: if the image distance works out to 2f, then the image size will be the same as the object size.
3. Converges; diverges.
4. When it passes NORMAL to the optical surface, In the case of a lens, this means along the lens axis.
5. Iris.

Answer 3

The key in the question is the "not parallel" part. A light ray that travels along the centerline of a lens, convex or not, doesn't bend because it meets both surfaces of the lens at a right angle. Unless the lens has an index of refraction equal to the medium surrounding it, that is the ONLY ray for which this is true. Figure your light paths according to the surface angle, just like any other place on the lens.

Answer 4

1. The light passing through the center (axis) of the lens would not be bent.

4. both materials have the same index of refraction
5. ciliary muscle

Answer 5

The optical center (It is the geometric center)

Th

Answer 6

1. focus point
2. 4 ft
3. concentrates; distributes
4. water
5. iris