Question

Which of the following statements is/are correct about a convex lens?

• A. Convex lens is converging for light for all wavelengths
• B. For virtual object, the image is also virtual
• C. For real object, the image is always real
• D. None of the above

Answer 1

Answer: (A), (B)

I. Convex lens is a converging lens provided refractive index of the material of the lens is greater than the surrounding medium in which the lens is kept.
From Lens makers formula,$\frac{1}{f}=\left({\mu }_2-1\right)\left(\frac{1}{R_1}-\frac{1}{R_2}\right)$
Refracting index of lens varies inversely with the wavelength of light used.
II. For virtual object, image is real for convex lens.

III. For object (real) between and $O$, image is virtual.