Skip to content
Login Register

#image size

2 public questions tagged with this topic.

Combination of Lenses and Lens Systems

What ensures that a convex mirror produces an image smaller than the object at all positions?

**Lens combination** effective focal length calculation uses reciprocal sum, for f₁=10 cm, f₂=20 cm in contact, 1/F=1/10+1/20=3/20, F=6.67 cm, P=15 D, stronger converging than either alone, illustrating power addition. A convex mirror diverges reflected rays, making them appear to come from a point closer to the mirror than the object. This divergence reduces the image size relative to the object, resulting in a diminished image regardless of the object’s distance from the mirror. Substituting values gives Divergence reducing image size, which matches expected image position and magnification

Ref: NCERT > Physics Book > Ray Optics > Combination of Lenses and Lens Systems

View Details
Refraction at Spherical Surfaces and Lens Maker's Formula

What happens to the image formed by a convex mirror if the object is moved closer to the mirror from a distant position?

**Refraction at spherical surface** formula n₁/u + n₂/v = (n₂-n₁)/R governs single surface, extension to two surfaces yields lens maker. Double convex with equal |R| has f = R/[2(n-1)], for R=12 cm, n=1.5, f=12 cm, illustrating dependence on curvature and index. A convex mirror always forms a virtual, erect, and diminished image. As the object moves closer, the image size increases slightly but remains diminished (less than the object size), and the image distance increases, approaching the focal length as a limit, though it never exceeds it. Substituting values gives Image size increases but

Ref: NCERT > Physics Book > Ray Optics > Refraction at Spherical Surfaces and Lens Maker's Formula

View Details