Can the dispersive power $\omega=\frac{\mu_\text{v}-\mu\text{r}}{\mu-1}$ be negative? What is the sign of co if a hollow prism is immersed into water?
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Dispersion and Spectra questions
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Suggest a method to produce a rainbow in your house.
The equation $\omega=\frac{\mu_\text{v}-\mu_\text{r}}{\mu-1}$ asderived for a prism having small refracting angle. Is it also valid for a prism of large refracting angle? Is it also valid for a glass slab or a glass sphere?
View full solution →If three identical prisms are combined, is it possible to pass a beam that emerges undeviated? Undispersed?
The minimum deviations suffered by red, yellow and violet beams passing through an equilateral transparent prism are 38.4°, 38.7° and 39.2° respectively. Calculate the dispersive power of the medium.
A thin prism of crown glass $(\mu_\text{r}=1.515,\mu_\text{v}=1.525)$ and a thin prism of flint glass $(\mu_\text{r}=1.612,\mu_\text{v}=1.632)$ are placed in contact with each other. Their refracting angles are 5.0° each and are similarly directed. Calculate the angular dispersion produced by the combination.
View full solution →The focal lengths of a convex lens for red, yellow and violet rays are 100cm, 98cm and 96cm respectively. Find the dispersive power of the material of the lens.
A thin prism is made of a material having refractive indices 1.61 and 1.65 for red and violet light. The dispersive power of the material is 0.07. It is found that a beam of yellow light passing through the prism suffers a minimum deviation of 4.0° in favourable conditions. Calculate the angle of the prism.
Two prisms of identical geometrical shape are combined with their refracting angles oppositely directed. The materials of the prisms have refractive indices 1.52 and 1.62 for violet light. A violet ray is deviated by 1.0° when passes symmetrically through this combination. What is the angle of the prisms?
A certain material has refractive indices 1.56, 1.60 and 1.68 for red, yellow and violet light respectively.
- Calculate the dispersive power.
- Find the angular dispersion produced by a thin prism of angle 6° made of this material.
prism can produce a minimum deviation $\delta$ in a light beam. If three such prisms are combined, the minimum deviation that can be produced in this beam is:
View full solution →-
$0$
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$\delta$
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$2\delta$
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$3\delta$
Which of the following quantities increase when wavelength is increased? Consider only the magnitudes.
- The power of a converging lens.
- The focal length of a converging lens.
- The power of a diverging lens.
- The focal length of a diverging lens.
Which of the following quantities related to a lens depend on the wavelength or wavelengths of the incident light?
- Power.
- Focal length.
- Chromatic aberration.
- Radii of curvature.
By properly combining two prisms made of different materials, it is possible to:
- Have dispersion without average deviation.
- Have deviation without dispersion.
- Have both dispersion and average deviation.
- Have neither dispersion nor average deviation.
If a glass prism is dipped in water, its dispersive power:
- Increases.
- Decreases.
- Does not change.
- May increase or decrease depending on whether the angle of the prism is less than or greater than 60°.
Three thin prisms are combined as shown in figure. The refractive indices of the crown glass for red, yellow and violet rays are $\mu_\text{r},\mu_\text{y}$ and $\mu_\text{v}$ respectively and those for the flint glass are $\mu'_\text{r},\mu'_\text{y}$ and $\mu'_\text{v}$ respectively. Find the ratio $\frac{\text{A}'}{\text{A}}$ for which.
View full solution →- There is no net angular dispersion.
- There is no net deviation in the yellow ray.
A thin prism of angle $6.0^\circ,\omega=0.07$ and $\mu_\text{y}=1.50$ is combined with another thin prism having $\omega=0.08$ and $\mu_\text{y}=1.60.$ The combination produces no deviation in the mean ray.
View full solution →- Find the angle of the second prism.
- Find the net angular dispersion produced by the combination when a beam of white light passes through it.
- If the prisms are similarly directed, what will be the deviation in the mean ray
- Find the angular dispersion in the situation described in (c).
The refractive index of a material M1 changes by 0.014 and that of another material M2 changes by 0.024 as the colour of the light is changed from red to violet. Two thin prisms one made of M1(A = 5.3°) and other made of M2(A = 3.7°) are combined with their refracting angles oppositely directed.
- Find the angular dispersion produced by the combination.
- The prisms are now combined with their refracting angles similarly directed. Find the angular dispersion produced by the combination.
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