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| Physics 10th Chapter 12 Geometrical Optics Questions Bank |
Physics 10th Chapter 12 Geometrical Optics Solved MCQs, Short and Long Questions
MCQs
Select the right Answer.
1. ? = speed of light in vacuum / speed of light in medium
2. 1D = ?
3. A line joining centre of curvature and pole of the spherical mirror is:
4. Conditions for total internal reflection are:
5. Critical angle is equal to:
6. Endoscope used to diagnose the stomach is;
7. Endoscope which is used to diagnose throat is;
8. If a ray of light in glass is incident on an air, surface at an angle greater than the critical angle, the ray will be:
9. In a lens, number of curved surfaces will be at least:
10. In concave mirror which surface is reflecting?
11. In totally reflecting prism one angle is of 90°, and other two angles are of:
12. In totally reflecting prism one angle is of:
13. It has positive focal length:
14. It is a transparent body (made of optical glass) with at least two polished plane faces inclined towards each other from which light is refracted:
15. It is used to explore the interior organs of the body?
16. Lens formula is
17. Lens thick at the centre but thin at the edges is:
18. Optical fibre works on the principal of:
19. Optical fibres are:
20. SI unit of power of lens is:
21. sin i / sin r = n = n2/n1
22. The angle at which prism deviates the incident ray is called:
23. The distance between the optical centre and the principal focus is:
24. The distance from the pole to the principal focus measured along the principal axis is:
25. The lens which causes incident parallel rays to converge at a point is:
26. The line passing through the two centres of curvatures of the lens is called:
27. The minimum value of angle of deviation is called:
28. The refracted light striking to the side of prims is called:
29. The refractive index of internal coating of optical fibre is:
30. The relationship between object distance p, image distance q from the mirror and focal length of the mirror is called:
31. The speed of light in water is approximately:
32. The speed of light is greater in:
33. The study of behaviour of light is called;
34. The bending of light as it passes from one transparent medium into another is:
35. To see from submarine and the ship at the surface of water, we use:
36. Totally reflecting prism turns the incident ray at an angle of:
37. When a ray of light enters from a denser medium to a rarer medium:
38. Which pipe is a bundle of thousand of optical fibres bounded together?
39. Which statement is correct about convex mirror?
40. Which statement is incorrect about concave mirror?
Short Questions
1. A man raises his left hand in a plane mirror, the image facing him is raising his right hand. Explain why?
2. Define convex lens and concave lens.
3. Define Critical angle.
4. Define lens.
5. Define optical centre and focal length of lens?
6. Define optical fibre.
7. Define refractive index.
8. Define total internal reflection.
9. Define unit of power of lens
10. Describe the passage of light through parallel sided transparent material.
11. Differentiate between concave and convex mirrors.
12. Differentiate between core and cladding of an optical fibre.
13. Differentiate between the focus of a concave &\quad convex mirror?
14. Draw the ray diagram for the virtual image in a plane mirror?
15. Explain the reflection of light by spherical mirrors with the help of diagram.
16. Explain why a fish under water appears to be at a different depth below the surface than it actually is. Does it appear deeper or shallower?
17. How does the thickness of a lens affect its focal length?
18. How does the combination of two triangular prisms resemble a concave or convex lens?
19. How light travels with the use of total internal reflection in optical fibre.
20. In your own words, explain why light waves are refracted at a boundary between two materials.
21. State law of refraction?
22. State Snell’s law?
23. Under what conditions will a converging lens form a virtual image?
24. Under what conditions will a converging lens form a real image that is the same size as the object?
25. What are spherical mirrors?
26. What are the characteristics of focus of a concave and a convex mirror?
27. What are the sign conventions for focal length in lenses?
28. What are the sign conventions for image distance in lenses?
29. What are the sign conventions for object distance in lenses?
30. What do you know about power of lens?
31. What do you know about principal axis and principal focus of lens?
32. What is Lens formula?
33. What is meant by mirror formula?
34. What is meant by refraction of light?
35. What is prism?
36. What is the relation between focal length and radius of a spherical mirror?
37. When an optician's testing room is small, he uses a mirror to help him test the eyesight of his patients. Explain why.
38. Why is the driver's side mirror in many cars convex rather than plane or concave?
39. Why do we use refracting telescope with large objective lens of large focal length?
40. Why or why not concave mirrors are suitable for makeup?
41. Why the focal length of a convex mirror is taken as negative?
42. Why the term magnification does is different from the term enlargement in optics?
43. Write conditions of total internal reflection.
44. Write down the sign conventions for concave and convex mirror.
45. Write down the uses of lens.
Long Questions
1. What do you understand by reflection of light? Draw a diagram to illustrate reflection at a plane surface.
"2. Describe the following terms used in reflection:
(i) normal (ii) angle of incidence (iii) angle of reflection"
3. State laws of reflection. Describe how they can be verified graphically.
4. Define refraction of light. Describe the passage of light through parallel-sided transparent material.
"5. Define the following terms used in refraction:
(i) angle of incidence (ii) angle of refraction "
6. What is meant by refractive index of a material? How would you determine the refractive index of a rectangular glass slab?
7. State the laws of refraction of light and show how they may be verified using rectangular glass slab and pins.
8. What is meant by the term total internal reflection. State the conditions for total internal reflection.
9. What is critical angle? Derive a relationship between the critical angle and the refractive index of a substance.
10. What are optical fibres? Describe how total internal reflection is used in light propagating through optical fibres.
"11. Define the following terms applied to a lens:
(i) principal axis (ii) optical centre (iii) focal length"
"12. What is meant by the principal focus of a (a) convex lens (b) concave lens?
Illustrate your answer with ray diagrams."
13. Describe how light is refracted through convex lens.
14. With the help of a ray diagram, how you can show the use of thin converging lens as a magnifying glass.
15. An object 10.0 cm in front of a convex mirror forms an image 5.0 cm behind the mirror . What is the focal length of the mirror?
16. An object 30 cm tall is located 10.5 cm from a concave mirror with focal length 16 cm. (a) Where is the image located? (b) How high is it?
17. An object and its image in a concave mirror are of the same height, yet inverted, when the object is 20 cm from the mirror . What is the focal length of the mirror?
18. Find the focal length of a mirror that forms an image 5.66 cm behind the mirror of an object placed at 34.4 cm in front of the mirror . Is the mirror concave or convex?
19. An image of a statue appears to be 11.5 cm behind a concave mirror with focal length 13.5 cm. Find the distance from the statue to the mirror .
20. An image is produced by a concave mirror of focal length 8.7 cm. The object is 13.2 cm tall and at a distance 19.3 cm from the mirror . (a) Find the location and of the image. (b) Find the height of the image produced by the height mirror if the object is twice as far from the mirror .
21. Nabeela uses a concave mirror when applying makeup. The mirror has a radius of curvature of 38 cm. (a) What is the focal length of the mirror? (b) Nabeela is located 50 cm from the mirror . Where will her image appear? (c) Will the image be upright or inverted?
22. An object 4 cm high is placed at a distance of 12 cm from a convex lens of focal length 8 cm. Calculate the position and size of the image. Also state the nature of the image.
23. An object 10 cm high is placed at a distance of 20 cm from a concave lens of focal length 15 cm. Calculate the position and size of the image. Also, state the nature of the image.
24. A convex lens of focal length 6 cm is to be used to form a virtual image three times the size of the object. Where must the lens be placed?
25. A ray of light from air is incident on a liquid surface at an angle of incidence 35 . Calculate the angle of refraction if the refractive index of the liquid is 1.25. Also calculate the critical angle between the liquid air inter-face.
26. The power of a convex lens is 5 D. At what distance the object should be placed from the lens so that its real and 2 times larger image is formed.