Physics · JEE | Ray Optics and Optical Instruments

Consider the following statements regarding refraction at spherical surfaces and lenses: (A) The lens maker's formula is valid for both convex and concave lenses. (B) The two principal foci of a double convex or concave lens are equidistant from the optical centre. (C) For an erect and virtual image formed by a lens, the magnification \( m \) is negative. (D) When several thin lenses are in contact, the net power is the algebraic sum of individual powers. How many of the above statements are correct?

1. A
   Only one
2. B
   Only two
3. C
   Only three
4. D
   All four