InterviewSolution
Saved Bookmarks
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.
| 201. |
Focal length of objective and eyepiece of telescope are 200 cm and 4 cm respectively. What is length of telescope for normal adjustment? (a) 196 cm (b) 204 cm (c) 250 cm (d) 225 cm |
|
Answer» (b) 204 cm Hint L =-f0 + fe = 200 + 4 = 204 cm |
|
| 202. |
In Cassegrainian telescope, objective lens is………by………… . |
| Answer» replaced , large concave mirror. | |
| 203. |
A thin prism `P_(1)` with angle `4degree` and made from glass of refractive index 1.54 is combined with another thin prism `P_(2)` made from glass of refractive index 1.72 to produce dispersion without deviation. The angle of the prism `P_(2)` isA. `5.33^(@)`B. `4^(@)`C. `3^(@)`D. `2.6^(@)` |
|
Answer» Correct Answer - C |
|
| 204. |
A thin prism of angle `15^(@)` 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 produces dispersion without deviation. The angle of the second prism should beA. `7^(@)`B. `10^(@)`C. `12^(@)`D. `5^(@)` |
|
Answer» Correct Answer - B Here, `A_(1) = 15^(@), mu_(1) = 1.5 , mu_(2) = 1.75, A_(2) = ?` There will be no deviation for the combination of two prism if net deviation is zero, i.e., `delta_(1) + delta_(2) = 0` or `(mu_(1) - 1) A_(1) + (mu_(2) - 1)A_(2) = 0` or `A_(2) = -((mu_(1) - 1)A_(1))/((mu_(2) - 1)) = - ((1.5 - 1) 5^(@))/((1.75 - 1)) = - 10^(@)` `-ve` sign shows that the second prism is placed in opposition to first prism. |
|
| 205. |
A beam of light is converging towards a certain point. A parallel sided glass plate is introduced in the path of the converging beam. How will the point of convergence be shifted ? |
| Answer» The point of convergence will be shifted away from the glass plate. | |
| 206. |
A plane mirror is placed at the bottom of a tank containing a liquid of refractive index μ. P is a small object at a height h above the mirror. An observer O—vertically above P, outside the liquid—sees P and its image in the mirror. The apparent distance between these two will be(a) 2μh (b) 2h/μ(c) 2h/μ - 1(d) h(1 + 1/μ) |
|
Answer» Correct Answer is: (b) 2h/μ The image of P will be formed at a distance h below the mirror. If d = depth of the liquid in the tank, apparent depth of P = x1 = d-h/μ, apparent depth of the image of P = x2 = d+h/μ, apparent distance between P and its image = x2 - x1 = 2h/μ. |
|
| 207. |
A plane mirror is placed at the bottom of the tank containing a liquid of refractive index `mu`. P is a small object at a height h above the mirror. An observer O vertically above P, outside the liquid sees P and its image in the mirror. The apparent distance between these two will beA. `2muh`B. `(2h)/(mu)`C. `(2h)/(mu-1)`D. `h(1+1/(mu))` |
|
Answer» Correct Answer - B |
|
| 208. |
Which part of the human eye changes the focal length of the eye lens?(a) pupil (b) retina (c) ciliary muscles (d) cornea |
|
Answer» (c) ciliary muscles |
|
| 209. |
Differentiate the eye defects: Myopia and Hypermetropia. |
||||||||||||||||||
Answer»
|
|||||||||||||||||||
| 210. |
Match the followingColumn - IColumn - II1. Retinaa. path way of light2. Pupilb. Far point comes closer3. Ciliary musclesc. Near point moves away4. Myopiad. Screen of the eye5. Hypemetropiaf. Power of accommodation |
|
Answer» 1. d 2. a 3. e 4. b 5. c |
|
| 211. |
What is the difference between hypermetropia and presbyopia ? |
| Answer» Hypermetropia is long sightedness. It may be due to contraction in size of the eye ball or increase in focal length of eye lens, when fully relaxed. Presbyopia is long sightedness due to old age when eye ball has normal length. Only the focal length of eye lens in fully relaxed position has increased. | |
| 212. |
Match the column I with Column IIColumn IColumn IIA.Myopia(i)Convex lensB.Hypemetropia(ii)Hyperbolic mirrosC.Presbyopia(iii)Concave lensD.Hubble space telescope(iv)Bi - focal lens |
|
Answer» A. (iii) B. (i) C. (iv) D. (ii) |
|
| 213. |
Two this lenses, when in contact, produce a combination of power `+10` diopters. When they are 0.25 m apart, the power reduces to `+6` diopters. The focal length of the lenses are…. `m` and …`m`. |
|
Answer» Here, `P_(I) = + 10 D, d = 0.25 m, P_(II) + 6 D` `f_(1) = ? F_(2) = ?` When the two lenses are in contact `P_(1) = P_(1) + P_(2) = 10` …(i) When the lenses are separated by `d = 0.5 m` `P_(II) = P_(1) + P_(2) - d P_(1) P_(2) = 6` `P_(1) + P_(2) - 0.25 P_(1) P_(2) = 6` ...(ii) Subtract (ii) from (i) `0.25 P_(1) P_(2) = 10 - 6 = 4` `P_(1) P_(2) = 16` Now, `P_(1) - P_(2) = sqrt((P_(1) + P_(2))^(2) - 4 P_(1)P_(2))` `= sqrt(10^(2) - 4 xx 16) = sqrt(36) = 6` ...(iii) Add (i) and (ii), `2 P_(1) = 16, P_(1) = 8 D` `P_(2) = 10 - P_(1) = 10 - 8 = 2 D` `f_(1) = (1)/(P_(1)) = (1)/(8)m = 0.125 m` `f_(2) = (1)/(P_(2)) = (1)/(2) = 0.5 m` |
|
| 214. |
Mie scattering is responsible for the _____ appearance of the clouds.(a) red (b) blue (c) colourless (d) white. |
|
Answer» Correct answer is (d) white |
|
| 215. |
Does the phenomenon of interference violate the energy conservation principle ? |
| Answer» No. In intereference, energy is only redistributed from regions of destructive interference. Energy is neither created nor destroyed. | |
| 216. |
Three immiscible liquids of densities `d_1 gt d_2 gt d_3` and refractive indices `mu_1 gt mu_2 gt mu_3` are put in a beaker. The height of each liquid column is `(h)/(3)`. A dot is made at the bottom of the beaker. For near normal vision, find the apparent depth of the dot. |
|
Answer» Here, real depth of the dot under liquid of density `d_(1)` is `h//3`. If `x_(1)` is its apparent depth, when seen from air, then from `mu_(1) = (h//3)/(x_(1)) or x_(1) = (h)/(3 mu_(1))` Similarly, apparent depths of the dot when seen from air through two other liquids are `x_(2) = (h)/(3 mu_(2)) and x_(3) = (h)/(3 mu_(3))` `:.` Apparent depth of the dot seen from air through the three liquids is `x = x_(1) + x_(2) + x_(3) = (h)/(3mu_(1)) + (h)/(3 mu_(2)) + (h)/(3 mu_(3)) = (h)/(3)[(1)/(mu_(1)) + (1)/(mu_(2)) + (1)/(mu_(3))]` |
|
| 217. |
A ray of light is incident normally on one of the faces of a prism of apex angle 30° and refractive index √2. The angle of deviation of the ray is (a) 0° (b) 12.5° (c) 15°(d) 22.5° |
|
Answer» Correct Answer is: (c) 15° |
|
| 218. |
The refractive indices of a prism for red, violet and yellow lights are `1.52, 1.62 and 1.59` recp.What is the dispersive power of the prism ? If mean deviation is `40^(@)`. What is angular dispersion produced by the prism ? |
|
Answer» Correct Answer - `0.169`; `6.76^(@)` Here, `mu_(r ) = 1.52, mu_(v) = 162` and `mu_(y) = 1.59` Dispersive power `(omega)` `= (mu_(v) - mu_(r ))/(mu_(y) - 1) = (1.62 - 1.52)/(1.59 - 1) = (0.10)/(0.59) = 0.169` Angular dispersion : `delta_(v) - delta_(r ) = omega xx delta` `= 0.169 xx 40^(@) = 6.76^(@)` |
|
| 219. |
An astronomical telescope often fold angular magnification has a length of 44 cm. The focal length of the object is(a) 4 cm (b) 40 cm (c) 44 cm(d) 440 cm |
|
Answer» (b) 40 cm Here, f0 + fe = 44 cm m =\(\frac{f_0}{f_e}\) (or) f0 = 10 fe ∴ 10 fe + 10 fe = 44 cm (or) fe = 4 cm Hence, f0 = 10 x 4 (or) f0 = 40 cm |
|
| 220. |
Brilliance of a diamond is due to (a) shape (b) cutting (c) reflection (d) total internal reflection |
|
Answer» (d) total internal reflection Brilliance of a diamond is due to total internal reflection of light. |
|
| 221. |
The blue colour of the sky is due to the phenomenon of (a) scattering (b) dispersion (c) reflection (d) refraction |
|
Answer» (a) scattering The blue colour of the sky is due to the scattering of sunlight by atmospheric molecules. |
|
| 222. |
Sparkling of diamond is due to (a) reflection (b) dispersion (c) total internal reflection d) high refractive index of diamond |
|
Answer» (c) total internal reflection |
|
| 223. |
Refractive index of red and violet light are 1.52 and 1.54 respectively. If the angle of prism is 10° , the angular dispersion will be(a) 0.02° (b) 0.20° (c) 3.06°(d) 30.6° |
|
Answer» (b) 0.20° Angular dispersion = δV – δR = A(μV – μV ) = 10° (1.54 – 1.52) = 0.20° |
|
| 224. |
Discuss the experiment to determine the wavelength of different colours using diffraction grating. |
|
Answer» Determination of wavelength of different colours: When white light is used, the diffraction pattern consists of a white central maximum and on both sides continuous coloured diffraction patterns are formed. The central maximum is white as all the colours meet here constructively with no path difference. As θ increases, the path difference, (a + b) sin θ, passes through condition for maxima of diffraction of different orders for all colours from violet to red. It produces a spectrum of diffraction pattern from violet to red on either side of central maximum. By measuring the angle at which these colours appear for various orders of diffraction, the wavelength of different colours could be calculated using the formula λ= \(\frac{sinθ}{Nm}\) Here, N is the number of rulings per metre in the grating and m is the order of the diffraction image. |
|
| 225. |
Is there any difference between colored light obtained from prism and colours of soap bubble? |
|
Answer» Yes. there is a difference between colored light obtained from the prism is the phenomenon of‘dispersion of light’ and colored light obtained from the soap bubble is the phenomenon of ‘interference of light’. |
|
| 226. |
For a double convex lens `R_(1)` is………….. And `R_(2)` is…………… . Therefore, its focal length is………… . |
| Answer» positive , negative , positive. | |
| 227. |
Does the value of polarizing angle depend on colour of light ? |
| Answer» Correct Answer - Yes, it depends. | |
| 228. |
To which wavelength of lights is our eye most sensitive ? In which region does this wavelength lie ? |
| Answer» Our eye is must sensitive to light of wavelength `5500 Å`. This wavelength lies in the yellow green region of visible spectrum. | |
| 229. |
In a Young’s double-slit experiment, let S1 and S2 be the two slits, and C be the centre of the screen. If ∠S1CS2 = θ and λ is the wavelength, the fringe width will be(a) λ/θ(b) λθ(c) 2λ/θ(d) λ/2θ |
|
Answer» Correct Answer is: (a) λ/θ β = λD/d and θ = d/D ∴ β = λ/θ. |
|
| 230. |
The angle of minimum deviation for a glass prism with `mu=sqrt3` equals the refracting angle of the prism. What is the angle of the prism? |
|
Answer» Here, `mu = sqrt(3), delta_(m) = A` From prism formula `mu = (sin (A + delta_(m))//2)/(sin A//2)` `sqrt(3) = (sin A)/(sin A//2) = (2 sin A//2 cos A//2)/(sin A//2) = 2 cos A//2` `cos A//2 = (sqrt(3))/(2) = cos 30^(@)` `A//2 = 30^(@) or A = 60^(@)` |
|
| 231. |
In a Young’s double-slit experiment, if the slits are of unequal width, (a) fringes will not be formed (b) the positions of minimum intensity will not be completely dark(c) bright fringe will not be formed at the centre of the screen (d) distance between two consecutive bright fringes will not be equal to the distance between two consecutive dark fringes |
|
Answer» Correct Answer is: (b) |
|
| 232. |
Assertion : A ray of light entering from glass to air suffers change in frequency. Reason : Velocity of light in glass is more than that ni air.A. If both, Assertion and Reason are true and the Reason is the correct explaination of the Assertion.B. If both, Assertion and Reason are true but Reason is not a correct explaination of the Assertion.C. If Assertion is true but the Reason is false.D. If both, Assertion and Reason are false. |
|
Answer» Correct Answer - D Both, the Asssertion and Reason are false. Frequency is that chracteristic property of light which does not change when light goes from one medium to another. So assertion is false. As glass is a denser medium in comparison ti air, velocity of light in glass is less than that in air. |
|
| 233. |
Is it possible to see primary and secondary rainbow simultaneously? Under what conditions? |
|
Answer» Yes, it is possible to see primary and secondary rainbows simultaneously. This can occur when the centres of both the rainbows coincide. |
|
| 234. |
what is a rainbow ? What is the essential condition for observing it ? |
| Answer» The observer must stand with his/her back towards the sun. | |
| 235. |
If an object moves towards a plane mirror with a speed v at an angle `theta` to the perpendicular to the plane of the mirror, find the relative velocity between the object and the image.A. `2v`B. `2v costheta`C. `2v sintheta`D. `2v//cos` |
|
Answer» Correct Answer - B |
|
| 236. |
A solid, transparent sphere has a small, opaque dot at its centre. When observed from outside, the apparent position of the dot will be (a) closer to the eye than its actual position (b) farther away from the eye than its actual position (c) the same as its actual position (d) independent of the refractive index of the sphere |
|
Answer» Correct Answer is: (c, d) μ2/v - μ1/u = μ2 - μ1 / r. Here, μ1 = μ refractive index of glass, μ2 = 1, u = -R = radius of sphere, r = -R. 1/v - μ/-R = 1 - μ / -R or 1/v = 1/-R or v =v- R. |
|
| 237. |
A watch glass has uniform thickness, and the average radius of curvature of its two surfaces is much larger than its thickness. It is placed in the path of a beam of parallel lilght. The beam willA. converge slightlyB. diverge slightlyC. be completely unaffectedD. converge or diverge slightly depending on whether the beam is incident from the concave or the convex side |
|
Answer» Correct Answer - B |
|
| 238. |
Where does a myopic eye focus the parallel rays falling in it ? |
| Answer» These rays are focusses in front of the retina. | |
| 239. |
In YDSE, two wavelengths of `500 nm and 700 nm` are used. What is the minimum their maxima coincide ? Take `D//d = 10^(3)`, symbols have standard meaning. |
|
Answer» Here, `lambda_(1) = 500 nm, lambda_(2) = 700 nm` Let `n_(1)th` maximum of `lambda_(1)` coincide with `n_(2)th` maximum of `lambda_(2)` `:. n_(1)(lambda_(1) D)/(d) = n_(2)(lambda_(2)D)/(d)` `(n_(1))/(n_(2)) = (lambda_(2))/(lambda_(1)) = (700)/(500) = (7)/(5)` `:.` `7th` maximum corresponding to `500 nm` coincides with `5th` maximum corresponding to`700nm`. After this, `14th` max. of `lambda_(1)` will coincide with `10th` max. of `lambda_(2)`. Hence the minimum distance from the central maximum, where the maxima due to two wavelengths coincide is `y_(1) = n_(1)(lambda_(1)D)/(d) = 7 xx (500 xx 10^(-9)) xx 10^(3)` `= 3.5 xx 10^(-3)m y = 3.5 mm`. |
|
| 240. |
The light reflected by a plane mirrorr may form a real imageA. if the rays incident on the mirror are convergingB. if the rays incident on the mirror are divergingC. if the object is placed very close to the mirrorD. under no circumstances |
|
Answer» Correct Answer - A |
|
| 241. |
A diverging lens of focal length `15 cm` forms an image `10 cm` from the lens. Calculate the distance of the object from the lens, given `mu = 1.5`. What is the linear magnification of the image ? |
|
Answer» Here, `f = - 15cm, v = -10 cm, u = ?, mu = 1.5` As `(1)/(v) - (1)/(u) = (1)/(f) :. (1)/(u) = (1)/(v) - (1)/(f) = (1)/(-10) + (1)/(15) = (-3 + 2)/(30) = (-1)/(30) :. u = -30 cm` Now, `m = (v)/(u) = (-10)/(-30) = (1)/(3)` |
|
| 242. |
Two lenses are placed in contact with each other and the focal length of combination is `80 cm`. If the focal length of one is `20 cm`, then the power of the other will be |
|
Answer» Here, `f = 80 cm, f_(1) = 20 cm, P_(2) = ?` `P = (100)/(F) = (100)/(80) = 1.25 D`, `P_(1) = (100)/(f_(1)) = (100)/(20) = 5 D` As `P_(1) + P_(2) = P :. P-(2) = P - P_(1) = P_(1) = 1.25 - 5 = -3.75 D` |
|
| 243. |
What colour do you observe when white light passes through a blue and yellow filter ? |
| Answer» When white light passes through a blue and yellow filter, we get green colour with a tinge of blue and yellow. This is because blue and yellow colours transmitted from these filters mix to produce green colour. | |
| 244. |
You are given four sources of light each one providing a light of a single colour-red, blue,green and yellow. Suppose the angle of refraction for a beam of yellow light corresponding to a particular angle of incidence at the interface of two media is `90^@`. Which of the folowing statements is correct it the source of yellow light is replaced with that of other lights without changing the angle of incidence ?A. The beam of red light would undergo total internal reflectionB. The beam of red light would bend towards normal white it gets refracted through the second mediumC. The beam of blue light would undergo total internal reflectionD. The beam of green light would bend away from the normal as it gets refracted through the second medium |
|
Answer» Correct Answer - C Here, for yellow light, `r = 90^(@)` when `I = C`. As `i` is kept same, `C` must be smaller for total internal reflection. From `mu = (1)/(sin C), C` will be smaller, when `mu` is larger. Out of given colours, `mu` is largest for blue colour. Critical angle will be smallest for the blue colour. Therefore, blue light would undergo total internal reflection. Chioce ( c) is correct. |
|
| 245. |
Assertion : Light shows the phenomena of interference, diffrection and polarisation. Reason : Because light behaves as corpuscles.A. If both, Assertion and Reason are true and the Reason is the correct explaination of the Assertion.B. If both, Assertion and Reason are true but Reason is not a correct explaination of the Assertion.C. If Assertion is true but the Reason is false.D. If both, Assertion and Reason are false. |
|
Answer» Correct Answer - C The phenomenon of interference, diffraction and polarisation are explained on the basis of wave nature of light. The assertion is true, but the reason is false. |
|
| 246. |
What is interference of light? |
|
Answer» The phenomenon of addition or superposition of two light waves which produces increase in intensity at some points and decrease in intensity at some other points is called interference of light. |
|
| 247. |
What is meant by one shift ? |
| Answer» When source of light and/or observer approach eachother, the apparent frequency of light increases or apparent wavelength decreases. This is called blue shift as wavelngth of blue colour is smaller. | |
| 248. |
What is phase of a wave? |
|
Answer» Phase is a particular point in time on the cycle of a waveform, measured as an angle in degrees. |
|
| 249. |
What is intensity division? |
|
Answer» Intensity’ or amplitude division: If we allow light to pass through a partially silvered mirror (beam splitter), both reflection and refraction take place simultaneously. As the two light beams are obtained from the same light source, the two divided light beams will be coherent beams. They will be either in-phase or at constant phase difference. |
|
| 250. |
Obtain the relation between phase difference and path difference |
|
Answer» Phase difference (Φ): It is the difference expressed in degrees or radians between two waves having same frequency and referenced to same point in time. Path difference (δ): It is the difference between the lengths of two paths of the two different having same frequency and travelling at same velocity. δ = \(\frac{λ}{2π}\)Φ |
|