Qstnid -Iii-5- Which Of The Following Quantities Increase When Wavelength Is Increased ? Consider Only The Magnitudes. - 20: Dispersion And Spectra - Neet-xii-physics

Home Learn Fast select Course

Show Unit/Chapter Change Unit Change Subject Last Menu

NEET-XII-Physics

20: dispersion and Spectra

with Solutions - page 2

Qstn# iii-5 Prvs-Qstn Next-Qstn

#5
Which of the following quantities increase when
wavelength is increased ? Consider only the magnitudes.
(a) The power of a converging lens.
(b) The focal length of a converging lens.
(c) The power of a diverging lens.
(d) The focal length of a diverging lens.
digAnsr: b,d
Ans : (b) The focal length of a converging lens
(d) The focal length of a diverging lens
The focal length of a lens is inversely proportional to the refractive index of the lens and the refractive index of the lens is inversely proportional to the square of wavelength. Therefore, the focal length is directly dependent on wavelength; it increases when the wavelength is increased.