If $ω$ is the dispersive power and $f$ is the mean focal length, then the longitudinal chromatic aberration is :

Question

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Answer 1

Longitudinal chromatic aberration occurs if a lens can not focus different colors in the same focal plane. It is caused by straight incident light. The foci of the different colors lie at different points in the longitudinal direction along the optical axis.
The longitudinal chromatic aberration is defined as the product of the dispersion power and the mean focal length.
Hence, $c = ω f$

Answer 2

Longitudinal chromatic aberration occurs if a lens can not focus different colors in the same focal plane. It is caused by straight incident light. The foci of the different colors lie at different points in the longitudinal direction along the optical axis.

The longitudinal chromatic aberration is defined as the product of the dispersion power and the mean focal length.
Hence,

c = ω f

If $ω$ is the dispersive power and $f$ is the mean focal length, then the longitudinal chromatic aberration is :

$\frac{ω}{f}$

$ω f$

$\frac{ω f}{2}$

$2 ω$ f

A convex lens of focal length 63 cm and dispersive power 0.21 is kept in contact with another lens of dispersive power 0.50 in order to make an achromatic doublet. The focal length of second lens is

The magnitude of longitudinal chromatic aberration produced by a convex lens for the pair of violet and red colours is 0.353 cm. If the focal length of the lens with respect to violet colour is 15.295 cm, the focal length of lens for red coloured rays is :

Assertion (A) : An achromatic combination of lens is needed for the minimisation of chromatic aberration.
Reason (R) : A single lens alone cannot satisfy the condition of minimisation of chromatic aberration

A convex lens of focal length 10 cm is combined with a concave lens of focal length 20 cm to form an achromatic combination. The convex lens is made of a material of dispersive power 0.016. The dispersive power of the material used for concave lens is

Two lenses of focal lengths $+ 10$ cm and $- 15$ cm when put in contact behave like a convex lens. They will have zero longitudinal chromatic aberration if their dispersive powers are in the ratio

If ω is the dispersive power and f is the mean focal length, then the longitudinal chromatic aberration is :

fω​

ωf

2ωf​

2ωf

A convex lens of focal length 63 cm and dispersive power 0.21 is kept in contact with another lens of dispersive power 0.50 in order to make an achromatic doublet. The focal length of second lens is

The magnitude of longitudinal chromatic aberration produced by a convex lens for the pair of violet and red colours is 0.353 cm. If the focal length of the lens with respect to violet colour is 15.295 cm, the focal length of lens for red coloured rays is :

Assertion (A) : An achromatic combination of lens is needed for the minimisation of chromatic aberration. Reason (R) : A single lens alone cannot satisfy the condition of minimisation of chromatic aberration

A convex lens of focal length 10 cm is combined with a concave lens of focal length 20 cm to form an achromatic combination. The convex lens is made of a material of dispersive power 0.016. The dispersive power of the material used for concave lens is

Two lenses of focal lengths +10 cm and −15cm when put in contact behave like a convex lens. They will have zero longitudinal chromatic aberration if their dispersive powers are in the ratio

If $ω$ is the dispersive power and $f$ is the mean focal length, then the longitudinal chromatic aberration is :

$\frac{ω}{f}$

$ω f$

$\frac{ω f}{2}$

$2 ω$ f

Assertion (A) : An achromatic combination of lens is needed for the minimisation of chromatic aberration.
Reason (R) : A single lens alone cannot satisfy the condition of minimisation of chromatic aberration

Two lenses of focal lengths $+ 10$ cm and $- 15$ cm when put in contact behave like a convex lens. They will have zero longitudinal chromatic aberration if their dispersive powers are in the ratio