Single Choice

The focal length of a convex lens depends upon

AFrequency of the light ray
BWavelength of the light ray
Correct Answer
CBoth $$(a)$$ and $$(b)$$
DNone of these

Solution

The focal length depends on the color of light because changing color changes wavelength which in turn changes the convergence point, so focus position changes and hence focal length also changes. It also depends on the curvature of the lens,
$$f \propto \dfrac{1}{\mu-1}$$ and $$\mu \propto \dfrac{1}{\lambda}$$

SIMILAR QUESTIONS

Optics

The focal length of converging lens are $$ { f }_{ v }\ and\ { f }_{ r }$$ for violet and red light respectively,then

Optics

Which of the following quantities increase when wavelength is increased? Consider only the magnitudes.

Optics

Which of the following quantities related to a lens depend on the wavelength or wavelength of the incident light?

Optics

A thin converging lens is placed between an object and a screen whose positions are fixed. There are two positions of the lens at which the sharp image of the object is formed on the screen. Find the transverse dimension of the object if at one position of the lens the image dimension equals $$ h^{\prime}=2.0 \mathrm{mm} $$ and at the other, $$ h^{\prime \prime}=4.5 \mathrm{mm} $$

Optics

A Galilean telescope of 10-fold magnification has a length of $$ 45 \mathrm{cm} $$ when adjusted to infinity. Determine: (a) the focal lengths of the telescope's objective and ocular;

Optics

The focal length of a concave mirror is $$f$$ and the distance from the object to the principal focus is $$x$$. The ratio of the size of the image to the size of the object is :

Optics

In order top obtain a real image of magnification $$2$$ bring a converging lens of focal length $$20cm$$, where should be an object be placed

Optics

Light of wavelength is $$7200\ \overset {o}{A}$$ in air. It has a wavelength in glass $$(\mu =1.5)$$ equal to

Optics

Which of the following is not a correct statement.

Optics

Focal length of a converging lens air in $$R$$. If it is dipped in water of refractive index $$1.33$$, then its focal length will be around (Refractive index of lens material is $$1.5$$)

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