Exams › NEET › Physics

If the focal length of objective lens is increased then magnifying power of:

1. microscope will increase but that of telescope decrease.
2. microscope and telescope both will increase.
3. microscope and telescope both will decrease.
4. microscope will decrease but that of telescope increase.

Correct answer: microscope will decrease but that of telescope increase.

Solution

For a microscope, increasing the focal length of the objective lens reduces its magnifying power as magnification is inversely proportional to the focal length. For a telescope, increasing the focal length of the objective lens increases its magnifying power as magnification is directly proportional to the focal length of the objective lens.

Related NEET Physics questions

• An image formed by a plane mirror is:
• One face of a rectangular glass plate 6 cm thick is silvered. An object held 8 cm in front of the first face forms an image 12 cm behind the silvered face. The refractive index of the glass is
• Time taken by sunlight to pass through a window of thickness 4 mm whose refractive index is 3/2 is
• A beam of monochromatic light is refracted from vacuum into a medium of refractive index 1.5, the wavelength of refracted light will be
• Green light of wavelength 5460 Å is incident on an air-glass interface. If the refractive index of glass is 1.5, the wavelength of light in glass would be (c = 3 × 10⁸ ms⁻¹)
• When a biconvex lens of glass having refractive index 1.47 is dipped in a liquid, it acts as a plane sheet of glass. This implies that the liquid must have refractive index.

⚔️ Practice NEET Physics free + battle 1v1 →