Question

What kind of image is produced by the achromatic combination of the lenses ?

• A. Formed images are not affected by the refractive indices of the lenses
• B. Blank coloured images are formed
• C. Black and white images are formed
• D. A point size image is formed

Answer 1

The correct option is A Formed images are not affected by the refractive indices of the lenses

We know that, achromatic combination of lenses is the combination of two lenses of different nature and of different focal lengths. Now, if we combine a convex and concave lens properly, the focal length of the combined lens will not change for different wavelengths of light . This combination of lenses is known as achromatic lens.
Due to achromatic combination of lenses, the image of the object is not affected by the variation of the refractive index with wavelength.
So, option $\left(a\right)$ is the correct answer.