Question

Objects less than $0.2$ $\mu m$ in size cannot be seen under light microscope because

• A. The wavelength of visible light is $4000$ $\stackrel{o}{A}$ to $7000\stackrel{o}{A}$
• B. Only two types of lenses are used
• C. Maximum magnifying power of ocular lens is $20$X
• D. Maximum magnifying power of objective lens is $100$X

Answer 1

The correct option is A The wavelength of visible light is $4000$ $\stackrel{o}{A}$ to $7000\stackrel{o}{A}$

The average wavelength of light used in microscopes is 500 - 600 nm. It gives a maximum resolution of 400 to 700 nm or 0.25 micrometer to 0.3 micrometer. Thus, if an object is closer than 0.25 micrometer, it will appear as one under the light microscope.

Thus, the correct answer is option A.