Questions
Three right angied prisms of refractive indices $\mu _1$,$\mu _2$ and $\mu _3$ are joined together so that the faces of the middle prism are each in contact with one the outside prism.If the ray passes through the composite block undeviated,then
- ${\mu _1}^2+{\mu _3}^2-{\mu _2}^2 = 1$
- ${\mu _1}^2-{\mu _3}^2+{\mu _2}^2 = 1$
- ${\mu _1}^2-{\mu _3}^2-{\mu _2}^2 = 1$
- ${\mu _2}^2+{\mu _3}^2-{\mu _1}^2 = 1$
Total reflecting prisms are _____ prism.
- Right angled
- Acute angled isosceles
- Right angled isosceles
- Obtuse angled isosceles.
An equilateral prism deviates a ray through $45^{\circ}$ for the two angles of incidence differing by $20^{\circ}.$ The angle of incidence is
- $62.5^{\circ}$
- $42.5^{\circ}$
- Both are correct
- Both are wrong
A light ray is incident normally on one of the refracting faces of a prism and just emerges out grazing the second surface. The relation between angle of the prism and its critical angle is
- $A=C$
- $A\neq C$
- $A< C$
- $A>C$
A ray of light is incident at an angle of $60^{\circ}$ on one face of a prism of angle $30^{\circ}$. The emergent ray of right makes an angle of $30^{\circ}$ with incident ray. The angle made by the emergent ray with second face of prism will be
- $0^{\circ}$
- $90^{\circ}$
- $45^{\circ}$
- $30^{\circ}$
A right-angled prism is set to deviate a ray of light through $90^o$ . If the same prism is to be used for deviating through $180^o$ , the prism must be turned from the previous set position through the angle :
- $45^o$
- $90^o$
- $135^o$
- $180^o$
Two thin prisms are combined to form an achromatic combination.For prism I, $ A=4^{0}, \mu _{R}=1.35, \mu _{Y}=1.40, \mu _{\nu}=1.42 . $ For prism II $ \mu _{R}=1.7, \mu _{\gamma}=1.8 $ and $ \mu _{R}=1.9 . $ Find the prism angle of prism II and the net mean deviation.
- $ 0.44^{\circ} $
- $ 0.45^{\circ} $
- $ 0.48^{\circ} $
- $ 0.46^{\circ} $
When light rays are incident on a prism at an angle of $45^o$, the minimum deviation is obtained. If the refractive index of the material of the prism is $\sqrt 3$, then the angle of prism will be
- $2 \times {\sin ^{ - 1}}\frac{1}{{\sqrt 6 }}$
- $45^o$
- $60^o$
- $90^o$
The angle of minimum deviation produced by an equilateral prism is $46^0$. The refractive index of material of the prism.
- 1.6
- 1.5
- 1.4
- 1.8
The dispersive powers of flint glass and crown glass are $0.053$ and $0.034 $and respectively and their mean refractive indices are $1.68 $ and $1.53$for white light. Calculate the angle of the flint prism required to form an achromatic combination with a crown glass of refracting angle $4^0$
- $2^0$
- $4^0$
- $5^0$
- $6^0$
The refractive index of a prism is 2. The prism can have a maximum refracting angle of
- $90^o$
- $60^o$
- $45^o$
- $30^o$
A ray of monochromatic light is incident on the refracting face of a prism (angle $75^o$). It passes through the prism and is incident on the other face at the critical angle. If the refractive index of the prism is $\sqrt 2$, then the angle of incidence on the first face of the prism is :
- $15^o$
- $30^o$
- $45^o$
- $60^o$
A beam of light consisting of red, green, and blue colors is incident on a right-angled prism. The refractive indices of the material of the prism for the above red, green, and blue wavelengths are 1.39, 1.44, and 1.47, respectively. The prism will
- separate part of the red color from the green and blue color
- separate part of the blue color from the red and green color
- separate all the three colors from one another
- not separate even partially any color from the other two colors
A thin prism of angle $7^o$ made of glass of refractive index $1.5$ is combined with another prism made of glass of $\mu =1.75$ to produce dispersion without deviation. The angle of second prism is :
- $7^o$
- $4.67^o$
- $9^o$
- $5^o$
A spectrum is obtained by sending a beam of white light through a prism. A second prism exactly similar to the first one is placed in an inverted position with the sides parallel to the first. Now
- A new spectrum will be formed on the screen with double the number of colours present in the previous spectrum
- New spectrum will be obtained on the screen with only half the number of colours present in the previous spectrum
- Previous spectrum will disappear and we will obtain a white light formed by the fusion of the colours
- A spectrum with same number of colours present in the previous spectrum will be formed but their wave lengths will be increased twice
A number of thin prism of prism angle $A$ and refractive index $\mu$ are arranged on periphery of circle such that any light ray entering from one prism move along a regular polygon
- number of prism used will be $\cfrac { 4\pi }{ (\mu -1)A } $
- If $A$ is rational, $\mu$ must be rational
- if $A$ is rational, $\mu$ must be irrational
- If $A$ is irrational, $\mu$ must be irrational
A ray of light is incident on the hypotenuse of a right-angled prism after travelling parallel to the base inside the prism. If $\mu $ is the refractive index of the material of the prism, the maximum value of the base angle for which light is totally reflected from the hypotenuse is :
- $sin^{-1}\left ( \dfrac{1}{\mu } \right )$
- $tan^{-1}\left ( \dfrac{1}{\mu } \right )$
- $sin^{-1}\left ( \dfrac{\mu -1}{\mu } \right )$
- $cos^{-1}\left ( \dfrac{1}{\mu } \right )$
A thin prism of angle $15^{o}$ made of glass of refractive index $\mu _{1} = 1.5$ is combined with another prism of glass of refractive index $\mu _{2} = 1.75$. The combination of the prism produced dispersion without deviation. The angle of the second prism should be :
- $5^{o}$
- $7^{o}$
- $10^{o}$
- $12^{o}$
A glass prism has a right-triangular cross-section ABC, with $\angle$A$=90^o$. A ray of light parallel to the hypotenuse BC and incident on the side AB emerges grazing the side AC. Another ray, again parallel to the hypotenuse BC, incident on the side AC suffers total internal reflection at the side AB. Find the range of the refractive index $\mu$ of the material of the prism?
- $\sqrt{\dfrac{3}{2}} < \mu < \sqrt 2$
- $\mu > \sqrt 3$
- $\mu < \sqrt{\dfrac{3}{2}}$
- $\sqrt 2 < \mu < \sqrt 3$
A thin prism $P _1$ with angle $6^o$ and made from glass of refractive index 1.54 is combined with another thin prism $P _2$ of refractive index 1.72 to produce dispersion without deviation. The angle of prism $P _2$ will be.
- $4^o 30'$
- $8.5^o$
- $6.5^o$
- None of these
The refracting angle of a prism $60^{\mathrm{o}}$.The refractive index of the material of the prism is $\sqrt{\dfrac{7}{3}}$. The limiting angle of incidence of a ray that will be transmitted through the prism in this case will be :
- $30^{0}$
- $45^{\mathrm{o}}$
- $40^{\mathrm{o}}$
- $50^{\mathrm{o}}$