Home › ICSE Class 10 › physics › Refraction through a Lens › An object 4 cm tall is placed 12 cm from a conve…
An object 4 cm tall is placed 12 cm from a convex lens of focal length 8 cm. The image is:
AVirtual, erect, 8 cm tall
BVirtual, erect, 4 cm tall
CReal, inverted, 4 cm tall
DReal, inverted, 8 cm tall
Answer & Solution
Correct answer: D. Real, inverted, 8 cm tall
1. Using 1/v - 1/u = 1/f with u = -12 cm and f = +8 cm.
2. 1/v = 1/8 + 1/(-12) = (3 - 2) / 24 = 1/24.
3. So v = +24 cm (image is real, on the other side).
4. m = v / u = 24 / (-12) = -2.
5. Image height = 4 * |-2| = 8 cm; inverted (since m is negative).
6. So image is real, inverted and 8 cm tall.
_Source: Selina Concise Physics ICSE Class 10, Ch 5 'Refraction through a Lens' (aplustopper.com extract)_
Related questions
Linear magnification produced by a converging lens for an object at 2F is:Cross-section of a convex lens looks like:Two lenses of powers +3 D and -5 D are placed in contact. The combination:A virtual image:Image formed by a convex lens with object at infinity is:If both surfaces of a thin lens have equal radii of curvature R, the lens is called:An object is placed beyond 2F from a convex lens. Image position is:Which is the principal use of a concave lens?