InterviewSolution

Explore topic-wise InterviewSolutions in .

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.

51.	A man stands in front of a mirror of special shape. He finds that his image has a very small head, a fat body, and legs of normal size. What can we say about the shapes of the three parts of the mirror?(a) Convex, Concave, Plane(b) The plane, Concave, Convex(c) Concave, Convex, Plane(d) Convex, Plane, ConcaveI have been asked this question by my school teacher while I was bunking the class.My question is taken from Reflection of Light by Spherical Mirrors in chapter Ray Optics and Optical Instruments of Physics – Class 12
Answer» RIGHT answer is (a) Convex, Concave, Plane To ELABORATE: The UPPER part of the mirror is convex. The middle part of the mirror is concave. The LOWER part of the mirror is plane. The image formed by a plane mirror will not have any changes, whereas that will not be the CASE for concave and convex mirrors.

52.	If the radius of curvature of each face of the biconcave lens, made of glass of refractive index 1.25 is 50 cm, then what is the focal length of the lens in air?(a) 30 cm(b) -30 cm(c) 5 cm(d) -5 cmI have been asked this question in an interview.I would like to ask this question from Reflection of Light by Spherical Mirrors topic in portion Ray Optics and Optical Instruments of Physics – Class 12
Answer» CORRECT choice is (b) -30 cm The best EXPLANATION: \(\FRAC {1}{f}\) = (μ-1)\( [ \frac {1}{R_1} – \frac {1}{R_2} ] \) \(\frac {1}{f}\) = (1.25 – 1)\( [ \frac {1}{-50} – \frac {1}{50} ] \) \(\frac {1}{f} = \frac {-1}{100}\) f = -100 cm Therefore, the focal LENGTH of the lens in AIR is -100 cm.

53.	A lens immersed in a transparent liquid is not visible. Under what condition can this happen?(a) Less refractive index(b) Higher refractive index(c) Same refractive index(d) Total internal reflection is zeroThe question was posed to me in examination.Question is from Ray Optics in portion Ray Optics and Optical Instruments of Physics – Class 12
Answer» Right answer is (c) Same refractive INDEX The explanation is: When the refractive index of the liquid is the same as the LENS material, no light will be REFLECTED by the lens and hence it will not be visible. So, the lens immersed in a TRANSPARENT liquid will not be visible.

54.	X is thicker in the middle than at the edges, whereas, Y is thicker at the edges than in the middle. Identify ‘X’ and ‘Y’.(a) X = concave lens; Y = convex lens(b) X = convex lens; Y = concave lens(c) X = plane lens; Y = convex lens(d) X = concave lens; Y = plane lensThis question was posed to me in semester exam.Origin of the question is Ray Optics topic in division Ray Optics and Optical Instruments of Physics – Class 12
Answer» The CORRECT answer is (B) X = CONVEX lens; Y = CONCAVE lens Best EXPLANATION: When the lens is thicker in the middle than at the edges, then it is convex lens. When the lens is thicker at the edges than in the middle, then it is concave lens. Therefore, X = convex lens, and Y = concave lens.

55.	On what factor does the normal shift through a refracting medium depend?(a) The thickness of the refracting medium(b) Angle of Prism(c) Angle of deviation(d) ConvectionThis question was posed to me in unit test.I need to ask this question from Ray Optics topic in chapter Ray Optics and Optical Instruments of Physics – Class 12
Answer» The correct choice is (a) The thickness of the refracting medium The explanation: The NORMAL shift DEPENDS on the thickness of the refracting medium and the REFRACTIVE INDEX of the material. The normal shift does not depend on the ANGLE of the prism, angle of deviation, and convection.

56.	Calculate the refractive index of the material of an equilateral prism for which the angle of minimum deviation is 60°.(a) \(\frac {\sqrt {3}}{2}\)(b) √3(c) \(\frac {1}{2}\)(d) \(\frac {1}{\sqrt {2}}\)This question was addressed to me in an interview for internship.I need to ask this question from Ray Optics in section Ray Optics and Optical Instruments of Physics – Class 12
Answer» CORRECT CHOICE is (b) √3 The explanation: Refractive index of the prism material is μ = \( \frac { \{ SIN \frac {(A+\delta_m)}{2} \} }{ \{sin \frac {A}{2} \} }\) μ = \( \frac { \{ sin \frac {(60^o+60^o)}{2} \} }{ \{ sin \frac {60^o}{2} \} } \) μ = √3.

57.	Identify the Lens Maker’s Formula.(a) f=(μ-1)\( ( \frac {1}{R_1} – \frac {1}{R_2} ) \)(b) \(\frac {1}{f}\)=(μ-1)\( ( \frac {1}{R_1} – \frac {1}{R_2} ) \)(c) \(\frac {1}{f}\)=(μ+1)\( ( \frac {1}{R_1} – \frac {1}{R_2} ) \)(d) \(\frac {1}{f}\)=(μ-1)\( ( \frac {1}{R_1} + \frac {1}{R_2} ) \)The question was posed to me in an interview.This is a very interesting question from Ray Optics in portion Ray Optics and Optical Instruments of Physics – Class 12
Answer» The CORRECT choice is (b) \(\frac {1}{f}\)=(μ-1)\( ( \frac {1}{R_1} – \frac {1}{R_2} ) \) The explanation is: The lens maker formula may be defined as the formula which gives the relationship for calculating the focal length in terms of the radii of the two curvatures of the lens. It is GIVEN as: \(\frac {1}{f}\)=(μ-1)\( ( \frac {1}{R_1} – \frac {1}{R_2} ) \) Where R1 and R2 are radii of CURVATURE of the two surfaces of the lens and μ is the refractive INDEX of the material of the lens w.r.t. medium in which the lens is PLACED.

58.	Which among the following is a portion of a transparent refracting medium bound by one spherical surface and the other plane surface?(a) Concave mirror(b) Plane mirror(c) Lens(d) PrismThe question was asked in a job interview.I would like to ask this question from Ray Optics topic in chapter Ray Optics and Optical Instruments of Physics – Class 12
Answer» Correct choice is (c) Lens Best explanation: Lens is a portion of a transparent refracting medium bound by two spherical surfaces or one spherical surface and the other plane surface. LENSES are DIVIDED into two classes, namely, CONVEX lens or converging lens, and CONCAVE lens or diverging lens.

59.	‘X’ is an optical illusion observed in deserts or over hot extended surfaces like a coal-tarred road, due to which a traveler sees a shimmering pond of water some distance ahead of him and in which the surrounding objects like trees appear inverted. Identify X.(a) Mileage(b) Mirage(c) Optical activity(d) Total internal reflectionThe question was asked in an international level competition.This intriguing question comes from Ray Optics topic in chapter Ray Optics and Optical Instruments of Physics – Class 12
Answer» The correct ANSWER is (b) Mirage The explanation: Mirage is an optical illusion observed in deserts or over hot EXTENDED surfaces like a coal-tarred road, DUE to which a traveler sees a shimmering pond of water some distance ahead of him and in which the surrounding objects like trees appear INVERTED.

60.	Which of the following causes refraction of light?(a) Change in the density of light from one medium to another(b) Change in viscosity of light from one medium to another(c) Change in the speed of light from one medium to another(d) Change in direction of light from one medium to anotherThis question was addressed to me in a job interview.This interesting question is from Reflection of Light by Spherical Mirrors topic in portion Ray Optics and Optical Instruments of Physics – Class 12
Answer» Right OPTION is (c) Change in the speed of LIGHT from ONE medium to another For explanation I would say: Light travels at different speeds in a different medium. The BENDING or refraction of light occurs due to the change in the speed of light as it passes from one medium to another. Other statements are not TRUE regarding the refraction of light.

61.	Two concave mirrors have the same focal length but the aperture of one is larger than that of the other. Which mirror forms the sharper image and why?(a) Plane(b) Concave(c) Convex(d) PrismI had been asked this question by my school principal while I was bunking the class.My query is from Reflection of Light by Spherical Mirrors in chapter Ray Optics and Optical Instruments of Physics – Class 12
Answer» The correct answer is (b) Concave Easiest EXPLANATION: The concave mirror with a smaller aperture FORMS the SHARPER image because it is FREE from spherical ABERRATION. So, even though both have the same focal length, the change of aperture affects the formation of the image.

62.	What will be the color of the sky in the absence of the atmosphere?(a) White(b) Dark(c) Blue(d) PinkThe question was posed to me in examination.My question is from Ray Optics in portion Ray Optics and Optical Instruments of Physics – Class 12
Answer» Correct answer is (b) DARK For EXPLANATION: The SUNLIGHT will not be scattered in the absence of the atmosphere. So the sky will appear dark. So, the sky will no longer be BLUE in the absence of an atmosphere.

63.	A concave mirror is held in water. What should be the change in the focal length of the mirror?(a) Halved(b) Doubled(c) Remains the same(d) Increases exponentiallyThe question was posed to me in an online interview.I'm obligated to ask this question of Reflection of Light by Spherical Mirrors in division Ray Optics and Optical Instruments of Physics – Class 12
Answer» Correct option is (c) Remains the same For explanation I WOULD say: No change. The focal LENGTH of a concave mirror does not depend on the nature of the MEDIUM. Therefore, the focal length of the mirror, even after holding it in water, will remain the same.

64.	Why is the sequence of colors in the secondary rainbow reverse of that in the primary rainbow?(a) Refraction of light(b) Two internal reflection(c) Reflection of light(d) DispersionThis question was addressed to me by my school principal while I was bunking the class.The doubt is from Ray Optics in portion Ray Optics and Optical Instruments of Physics – Class 12
Answer» The correct choice is (b) TWO INTERNAL reflection To EXPLAIN: The sequence of colors in the secondary rainbow is the reverse of that in the primary rainbow because a secondary rainbow is formed by two internal REFLECTIONS of light in WATER droplets while a primary rainbow is formed by just one total internal reflection.