a) Two lenses A and B have power of i) `+2D` and ii) `-4 D` respectively. What is the nature and focal length of each lens?
b) An object is placed at a distance of 100 cm from each of the above lenses A and B. Calculate i) image distance, and ii) magnification, in each of the two cases.

(a) Two lenses have power of (i) + 2D (ii) -4 D. What is the nature and focal length of each lens ? (b) An object is kept at a distance of 100 cm from each of above lenses. Calculate the (i) image distance of 100 cm from each of above lenses. Calculate the (i) image distance (ii) magnification in each of the two cases.

An object is placed at a distance of 100 cm from a converging lens of focal length 40 cm. i) What is the nature of image? ii) What is the position of image?

Two lenses A and B have focal length of +20 cm and, -10 cm, respectively. a) What is the nature of lens A and lens B? b) What is the power of lens A and lens B? What is the power of combination if lenses A and B are held close together?

An object of height 4.25 mm is placed at a distance 10 cm from a convex lens of power +5 D. Find (i) focal length of the lens, and ii) size of the image.

Two thin lenses of powers 2D and 4D are placed in close contact. An object is placed at a distance of 50 cm from the combination. What is the distance of the image from the combined lens ?

Two thin lenses of powers 2D and 3D are placed in contact. An object is placed at a distance of 30 cm from the combination The distance in cm of the image from the combination is

Two lenses of power -1.75D and +2.25 D respectively, are placed in contact. Calculate the focal length of the combination.