InterviewSolution
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InterviewSolution
This section includes InterviewSolutions, each offering curated multiple-choice questions to sharpen your knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
A man standing in a swimming pool looks at a stone lying at the bottom. The depth of the swimming pool is h. At what distance from the surface of water is the image of the stone formed -A. `h/mu`B. `mu/h`C. `h`D. `muh` |
| Answer» Correct Answer - A | |
| 2. |
A fish in water sees an object which is `24cm` above the surface of water. The height of the object above the surface of water that will appear to the flash is `(mu=4//3)`A. `24cm`B. `32cm`C. `18cm`D. `48cm` |
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Answer» Correct Answer - B Apparent height `=muh=4/3xx24=32cm` |
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| 3. |
A ray of light is incident on the surface of a glass plate of thickness `t`. If the angle of incidence `theta` is small, the emerging ray would be displaced side ways by an amount (Take `n` = refractive index of glass)A. `tthetan//(n+1)`B. `ttheta(n-1)//n`C. `tthetan//(n-1)`D. `ttheta//(n+1)//n` |
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Answer» Correct Answer - B Lateral shift `y=(tsin(i-r))/(cosr)=tsini-tcosi(sinr)/(cosr)` `(1xxsini=nsinr)` `=tsini-tcost(sini//n)/(sqrt(1-(sin^2i)/(n^2)))=tsini[1-(cosi)/(sqrt(n^2-sin^2i))]` When i is small, `sin^2 i` is negligible, `cos i=1`, `sin i=sin theta=theta` `=ttheta(1-1/n)=(ttheta(n-1))/(n)` |
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| 4. |
Light passes through a glass slab with parallel sides and thickness t. If i and r the angles of incidence of refraction, the lateral displacement isA. `tsin(i-r)`B. `tcosr`C. `tsin(i-r)//cosr`D. `t tan r` |
| Answer» Correct Answer - C | |
| 5. |
A fish looking up through the water sees the outside world contained in a circular horizon. If the refractive index of water is `4//3` and the fish is `12cm` below the surface, the radius of this circle in cm isA. `36sqrt5`B. `4sqrt5`C. `36sqrt7`D. `36//sqrt7` |
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Answer» Correct Answer - D Consider the above diagram `R/h=tanC=(sinC)/(cosC)=(1//mu)/(sqrt(1-1/mu^2))=(1)/(sqrt(mu^2-1))` `R=(h)/(sqrt(mu^2-1))=(12)/(sqrt((4/3)^2-1))=(12xx3)/(sqrt7)=(36)/(sqrt7)cm` |
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| 6. |
The apparent depth of water in cylindrical water tank of diameter `2R cm` is reducing at the rate of `x cm // min ` when water is being drained out at a constant rate. The amount of water drained in `c.c.` per minute is `(n_(1)=` refractive index of air, `n_(2)=` refractive index of water )A. `xpiR^2n_1/n_2`B. `xpiR^2n_2//n_1`C. `2piR^2n_1//n_2`D. `piR^2x` |
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Answer» Correct Answer - B Apparent depth `h_1=(h)/(._(air)n_(liq))=(h)/(n_2//n_1)` `h=(n_2)/(n_1)h_1` `(dh)/(dt)=n_2/n_1(dh_1)/(dt)=(n_2)/(n_1)x` `(dV)/(dt)=piR^2(dh)/(dt)=(n_2/n_1)piR^2x` |
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| 7. |
The refractive index of water, glass and diamond are `1.33`, `1.50`, `2.40` respectively. The refractive index of diamond relative to water and of glass relative of diamond, respectively are nearlyA. `1.80`, `0.625`B. `0.554`, `0.625`C. `1.80`, `1.6`D. `0.554`, `1.6` |
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Answer» Correct Answer - A `._amu_omega=1.33, ._amu_g=1.5, ._amu_d=2.4` `._omegamu_d=(._amu_d)/(._amu_omega)=(2.4)/(1.33)=1.80` `._dmu_g=(._amu_g)/(._amu_d)=(1.5)/(2.4)=0.625` |
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| 8. |
A ray of light is incident at the glass-water interface at an angle I, it emerges fimally parallel to the surface of water, the the value of `mu_g` would be A. `(4//3)sini`B. `1//sini`C. `4//3`D. `1` |
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Answer» Correct Answer - B Glass-water: `mu_gsini=mu_omegasinr` Water-air: `mu_omegasinr=mu_asin90^@` `mu_gsini=mu_asin90^@=1` `mu_g=1//sini` |
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| 9. |
If `._imu_j` represnts the refractive index when a ray of light goes from medium i to j, then the product `._2mu_1xx._1mu_3xx._3mu_4` is equal toA. `._3mu_1`B. `._3mu_2`C. `._2mu_3`D. `._2mu_4` |
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Answer» Correct Answer - D `._2mu_1xx._1mu_3xx._3mu_4=(mu_1)/(mu_2)xx(mu_3)/(mu_1)xx(mu_4)/(mu_3)=(mu_4)/(mu_2)=._2mu_4` |
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| 10. |
A prism of a certain angle deviates the red and blue rays by `8^@` and `12^@` respectively. Another prism of the same angle deviates the red and blue rays by `10^@` and `14^@` respectively. The prisms are small angled and made of different materials. The dispersive powers of the materials of the prisms are in the ratioA. `5:6`B. `9:11`C. `6:5`D. `11:9` |
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Answer» Correct Answer - C Prism (1), `omega_1=(delta_B-delta_R)/(delta)=(12-8)/(10)` (Since `delta=(delta_B+delta_R)/(2)`) `=4//10=2//5` Prism (2), `omega_2=(delta_B-delta_R)/(delta)=(14-10)/(12)=1/3` `omega_1//omega_2=(2//5)/(1//3)=6/5` |
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| 11. |
When a glass prism of refracting angle `60^(@)` is immersed in a liquid its angle of minimum deviation is `30^(@)`. The critical angle of glass with respect to the liquid medium isA. `42^@`B. `45^@`C. `50^@`D. `52^@` |
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Answer» Correct Answer - B `._lmu_g=(sin((A+delta_m)/(2)))/(sin(A/2))=(sin((60+30)/(2)))/(sin(60/2))=(sin45^@)/(sin30^@)` `=(1//sqrt2)/(1//2)=sqrt2` `._amu_gsinC=._amu_lsin90^@` `sinC=(._amu_l)/(._amu_g)=(1)/(._lmu_g)=1/sqrt2impliesC=45^@` |
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| 12. |
A graph is plotted between angle of deviation `(delta)` and angle of incidence (i) for a prism. The nearly correct graph isA. B. C. D. |
| Answer» Correct Answer - A | |
| 13. |
For a small angled prism, angle of prism `A` of minimum deviation`(delta)` varies with the refractive index of the prism as shown in the graph A. Point P corresponds to `mu=1//2`B. Slope of the line `PQ=A//2`C. Slope=AD. None of the above statements is true |
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Answer» Correct Answer - C `delta=(mu-1)Aimpliesy=(x-1)A=xA-A` Comparing with `y=mx+C` Slope: `m=A` |
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| 14. |
When a ray of light is refracted by a prism such that the angle of deviation is minimum, thenA. the angle of emergence is equal to the angle of incidenceB. the angle of emergence is greater than the angle of incidenceC. the angle of emergence is smaller than the angle of incidenceD. the sum of the angle of incidence and angle of emergence is equal to `90^@` |
| Answer» Correct Answer - A | |
| 15. |
Which of the following is not due to total internal reflection ?A. Brilliance of diamondB. Working of optical fibreC. Difference between apparent and real depth of a pondD. Mirage on hot summer days |
| Answer» Correct Answer - C | |
| 16. |
The angular dispersion produced by a prismA. increases if the average refractive index increasesB. increases if the average refractive index decreasesC. remains constant whether the average refractive index increases or decreasesD. has no relation with average refractive index |
| Answer» Correct Answer - A | |
| 17. |
By properly combining two prisms made of different materials, it is possible to (choose the incorrect option)A. have dispersion without average deviationB. have deviation without dispersionC. have both dispersion and average deviationD. have neither dispersion nor a average deviation |
| Answer» Correct Answer - D | |
| 18. |
The refractive index of glass with respect to water is `(9//8)`. Refractive index of water with respect to air is `(4//3)`. Find refractive index of glass with air. |
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Answer» Given `._omega mu_(s) = (9)/(8),_(a)mu_(omega) = (4)/(3)` `._(a)mu_(g)=_(a) mu_(omega) xx _(omega)mu_(g) = (4)/(3) xx (9)/(8) = (3)/(2)` |
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| 19. |
When light moves from one medium to another (i) the frequency of light remains same and wavelength changes (ii) refractive index of a medium is the ratio of speed of light in vacuum and speed of light in medium (iii) refractive index of a medium is the ratio of wavelength of light in vacuum and wavelength in medium (iv) for denser medium, the value of refractive index is largerA. (i), (ii)B. (ii), (iii)C. (ii), (iii), (iv)D. all options are correct |
| Answer» Correct Answer - D | |
| 20. |
If speed of light in a medium is `2xx10^8m//sec`. Find refractive index of medium. |
| Answer» `mu=c/v=(3xx10^8)/(2xx10^8)=3/2` | |
| 21. |
Find the speed of light of wavelength `lambda=600nm` (in air) in a medium of refractive index `5//3` and also wavelength of this light in medium. |
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Answer» `mu = (c)/(v) rArr v = (c)/(mu) = (3 xx 10^(8))/((5)/(3)) = (9)/(5) xx 10^(s) = 1.8 xx 10^(8) m//sec` `lambda = (lambda_(0))/(mu) = (600)/(5//3) = (1800)/(5) = 360 n m` |
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| 22. |
The speed of light in medium A is `2.0xx10^8m//sec` and that in medium B is `2.4xx10^8m//sec`. The critical angle of incidence for light tending to go from medium A to medium B isA. `sin^-1.(5)/(12)`B. `sin^-1.(5)/(6)`C. `sin^(-1).(2)/(3)`D. `sin^(-1).(3)/(4)` |
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Answer» Correct Answer - B `mu_Asini=mu_Bsinr` `mu_AsinC=mu_Bsin90^@` `(sinC)/(v_A)=1/v_B` (Since `muprop1/v`) `sinC=v_A/v_B=(2)/(2.4)=5/6impliesC=sin^-1(5/6)` |
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| 23. |
Light of wavelength `500nm` in medium A enters into medium B through a plane surface. If frequency of light is `4xx10^(14)Hz` and `v_A//v_B=4//5`, find absolute refractive indices of media A and B. |
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Answer» `v_A=upsilonlambda_A=4xx10^(14)xx500xx10^-9=2xx10^8 m//sec` `mu_A=(c)/(v_A)=(3xx10^8)/(2xx10^8)=3/2` `muprop1/v` `(mu_A)/(mu_B)=(v_B)/(v_A)implies(3//2)/(mu_B)=5/4` `mu_B=0.8xx1.5=1.2` |
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| 24. |
Absolute refractive indices of glass and water are `3//2` and `4//3`. The ratio of velocity of light in glass and water will beA. `4:3`B. `8:7`C. `8:9`D. `3:4` |
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Answer» Correct Answer - C `vprop1//mu` `(v_g)/(v_omega)=(._amu_omega)/(._amu_g)=(4//3)/(3//2)=8/9` |
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| 25. |
Critical angle is minimum when a light ray passes fromA. air to glassB. glass to airC. glass to waterD. water to glass |
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Answer» Correct Answer - B Glass to air, `mu_gsinC_1=1xxsin90^@` `sinC_1=(1)/(mu_g)` Glass to water, `mu_gsinC_2=mu_omegasin90^@` `sinC_2=(mu_omega)/(mu_g)` `mu_omegagt1`, `sinC_2gtsinC_1impliesC_2gtC_1` |
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| 26. |
Critical angle of light passing from glass to water is minimum forA. red colourB. green colourC. yellow colourD. violet colour |
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Answer» Correct Answer - D `mu_gsinC=mu_omegasin90^@` `sinC=(mu_omega)/(mu_g)=(1)/(._omegamu_g)` `mu` is maximum for violet colour, hence critical angle is minimum for violet colour. |
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| 27. |
Dispersion can take place forA. transverse wave only but not for longitudinal wavesB. longitudinal waves only but not for transverse wavesC. both transverse and longitudinal wavesD. neither transverse nor longitudinal waves |
| Answer» Correct Answer - C | |
| 28. |
A medium is said to be dispersive ifA. light of different wavelenghts propagate at different speedsB. light of different wavelengths propagate at same speed but has different frequenciesC. light is gradually bent rather than sharply refracted at an interface between the medium and airD. light is never totally internally reflected |
| Answer» Correct Answer - A | |
| 29. |
If a glass prism is dipped in water, its dispersive powerA. increasesB. decreasesC. does not changeD. may increase or decrease depending on whether the angle of prism is less than or greater than `60^@` |
| Answer» Correct Answer - B | |
| 30. |
Dispersive power depends uponA. the shape of prismB. material of prismC. angle of prismD. height of the prism |
| Answer» Correct Answer - B | |
| 31. |
If D is the deviation of a normally falling light beam on a thin prism of anlge A and `omega` is the dispersive power of the same prism thenA. D is independent of AB. D is independent of refractive indexC. `omega` is independent of refractive indexD. `omega` is independent of A |
| Answer» Correct Answer - D | |
| 32. |
A, B and C are three optical media of respective critical angles `C_1`, `C_2` and `C_3`. Total internal reflection of light can occur from A and B and also from B to C but not from C to A. Then the correct relation between critical angles isA. `C_1 gt C_2 gt C_3`B. `C_1=C_2=C_3`C. `C_3 gt C_1 gt C_2`D. `C_1 lt C_2 lt C_3` |
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Answer» Correct Answer - D T.I.R. can occur from A to B i.e. `mu_Agtmu_B`. B to C i.e. `mu_Bgtmu_C` `mu_Agtmu_Bgtmu_C` `sinC=1/muimpliesmu=(1)/(sinC)` `(1)/(sin C_1)gt(1)/(sinC_2)gt(1)/(sinC_3)` `sinC_1 lt sinC_2 lt sinC_3` `C_1 lt C_2 lt C_3` |
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| 33. |
Consider telecommunication through optical fibres. Which of the following statements is not true?A. Optical fibres may have homogenous core with a suitable claddingB. Optical fibres can be of graded refractive indexC. Optical fibres are subject to electromagnetic interference from outsideD. Optical fibres have extremely low transmission loss |
| Answer» Correct Answer - C | |
| 34. |
A concave mirror with its optic axis vertical and mirror facinig upward is placed at the bottom of the water tank. The radius of curvature of the mirror is 40 cm and refractive index for water `mu=4//3` . The tank is 20 cm deep and if a bird is flying over the tank at a height of 60 cm above the surface of water, find the position of image of the bird.A. `30cm`B. `10cm`C. `7.5cm` belowD. `7.5cm` above |
| Answer» Correct Answer - D | |
| 35. |
The mean distance of sun from the earth is `1.5xx10^8km`. The time taken by light to reach earth from the sun isA. `0.12min`B. `8.33min`C. `12.5min`D. `6.25min` |
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Answer» Correct Answer - B `t=d/c=(1.5xx10^8xx10^3)/(3xx10^8)=500sec` `=(500)/(60)=(50)/(6)=8.3min` |
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| 36. |
White light is incident on the interface of glass and air as shown in figure. If green ligth is just totally internally reflected then the emerging ray in air contains A. yellow, orange, redB. violet, indigo, blueC. all coloursD. all colours except green |
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Answer» Correct Answer - A `underset("V I B G Y O R")rarrmu` decreases `sinC=1/mu` As `mu` increases, C decreases. If green ligth is just totally reflected, violet, indigo, blue will be totally reflected because critical angles for them would be smaller than critical angle for green. |
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