Question

Analyse the following observation table showing variation of image-distance ( )v with object-

distance ( )u in case of a convex lens and answer the questions that follow without doing any

calculations

1 The focal length of convex lens is

(a) 5 cm (b) 10 cm

(c) 15 cm (d) 20 cm

2 For what object-distance (u)u is the corresponding image-distance (v)v not correct?

(a) 1st observation
(b) 2nd observation

(c) 6th observation
(d) 5th observation

3 A concave mirror gives real, inverted and same size image if the object is placed

(a) At focus
(b) At infinity

(c) At C i.e. centre of curvature (d) Beyond centre of curvature

5 The relation between focal length, image distance and object distance is

(a) 1/v = 1/v-1/u

(b) 1/v = 1/f+1/u
(c) 1/f = 1/v+1/u
(d) 1/f = 1/u-1/v​

Answer 1

Answer:

1- c option is right

2-c option is right

3-c option is right

5-c option is right