MCQs for Class 10 Science Book Chapter 10 “Light Reflection and Refraction”

 

Q1- In an astronomical telescope the focal length of objective lens is 100 cm and that of eyepiece is 2 cm. The magnifying power of the telescope for the normal eye is : A) 1/50 B) 100 C) 10 D) 50

Q2- A ray reflected successively from two plane mirrors inclined at a certain angle undergoes a deviation of 3000 . Then the number of images observable is : A) 60 B) 12 C) 11 D) 5

Q3- Light with wavelength of 6000 A0 units has a frequency : A) 5 x 10¹⁷ Hz B) 5 x 10¹⁶ Hz C) 5 x 10¹⁵ Hz D) 5 x 10¹⁴ Hz

Q4- Large aperture objects are used in telescopes because they : A) Have better dispersion B) Have less aberration C) Have better resolution D) Can see larger objects

 

 

 

 

 

Q5- At what distance from a screen will a 27 Cd lamp provide the same illumination as a 75 Cd lamp 15 m from the screen ? A) 9 m B) 6 m C) 3 m D) 1 m

Q6- Monochromatic light of frequency 5 x 10⁴ Hz travelling in vacuum enters a medium of refractive index 1.5. Its wavelength in the medium is : A) 5000 A0 B) 4000 A0 C) 5500 A0 D) 6000 A0

Q7- Two thin lenses, one of focal length +60 cm and the other of focal length -20 cm are kept in contact. Their combined focal length is A) Minus 30 cm B) Plus 30 cm C) Minus 15 cm D) Plus 30 cm

Q8- The focal length of a concave mirror is f and the distance of the object to the principal focus is p . Then the ratio of the size of the image to the size of the object is : A) p/p B) p/f C) fp D) (?pf)

Q9- For which of the given is luminous efficiency maximum ? A) Sodium vapour lamp B) Mercury vapour lamp C) Arc lamp D) Tungsten filament lamp

Q10- When light travels from one medium to other whose refractive index is different, then which of the given will change? A) Wavelength and velocity B) Frequency and wavelength C) Frequency and wavelength D) Frequency, wavelength and velocity

Q11- A blue object on a white background when seen through a blue filter will appear : A) Black on a blue background B) Blue on a white background C) Blue on a red background D) Invisible

Q12- In a photometer two sources of light when placed at 30 and 50 cm respectively produce shadow of equal intervals. Their candles are in the ratio of A) 9/25 B) 16/25 C) 3/5 D) 6/25

Q13- Spherical air bubble in water will act as : A) A concave lens B) A convex lens C) Plane-concave lens D) Plane glass plate

Q14- A ray of light is incident on a plane mirror at an angle of incidence 300 . The ray after reflection is deviated through : A) 30 degree B) 60 degree C) 90 degree D) 120 degree

Q15- The number of images observable between two parallel mirrors is : A) 2 B) 4 C) 6 D) Infinity

Q16- f = r/2 is valid : A) For convex mirrors but not for concave mirrors B) For concave mirrors but not for convex mirrors C) For both convex and concave mirrors D) Neither for convex mirrors nor for concave mirrors

Q17- Laser is : A) Coherent and monochromatic only B) Intense and monochromatic only C) Intense and coherent only D) Intense coherent and monochromatic

Q18- The focal length of a plano-convex lens having a radius of curvature of 10 cm for convex surface and a refractive index of 1.5 will be : A) 20 cm B) 15 cm C) 10 cm D) 5 cm

Q19- If in a plano-convex lens the radius of curvature of the convex surface is 10 cm and the focal length of the lens is 30 cm then the refractive index of the material of lens will be : A) 1.33 B) 3 C) 1.66 D) 1.5

 

 

 

 

Q20- Total internal reflection of light is possible when light enters from : A) Water to air B) Air to water C) Vacuum to air D) Air to glass

Q21- Magnifying power of a compound microscope is the ratio of the angle formed by the final image to the angle formed by the object when : A) Image is at the least distance of distinct vision and object may be anywhere B) Object and image are both at infinity C) Object and image are both at the least distance of distinct vision D) Object is placed at the least distance of distinct vision and image may be at any place

Q22- When white light moves through vacuum : A) Violet has greater speed than red B) Red has greater speed than violet C) All colours have the same speed D) Different colours have different random speeds

Q23- Refractive index of a material for infrared light is : A) Equal to that for red colour of light B) Equal to that for ultraviolet light C) Less than that for ultraviolet light D) Greater than that for ultraviolet light

Q24- A hole is made in a convex lens . Then : A) A hole appears in the image B) Image size decreases C) Image intensity decreases D) No change

Q25- Critical angle of light passing from glass to air is minimum for : A) Red B) Green C) Yellow D) Violet

Q26- Which of the given is not true of an image formed by a plane mirror ? A) It is erect B) It is virtual C) It is diminished D) It is at the same distance as the object

Q27- Two lenses of power +3 and -1 diopters are placed in contact. The focal length of the combined lens is : A) 100 cm B) 25 cm C) 50 cm D) 30.3 cm

Q28- The focal length of a concave mirror is 50 cm. To obtain an inverted image two times the size of the object the object should be placed at : A) 50 cm B) 63 cm C) 72 cm D) 75 cm

Q29- What is the minimum distance between an object and its virtual image in case of a concave lens ? A) 0 B) f C) 2f D) 4f

Q30- The focal length of lens depends on : A) The radii of curvature of its surfaces B) The refractive index of its material C) The refractive index of the medium surrounding D) All of the these factors

Q31- A parallel beam of light is incident on a converging lens parallel to its principal axis. As we move away from the lens on the other side on its principal axis the intensity of light A) Remains constant B) Continuously increases C) Continuously decreases D) First increases and then decreases

Q32- Using a convex lens, a clear image of candle flame is produced on a screen. How many other clear images can be received on this screen if only the lens is to be shifted ? A) A large number B) Only one more C) Two more D) None of these

Q33- A convex lens of power P is immersed in a water . How will its power change ? A) Increases B) Remain unchanged C) Decreases D) Increases for red colour and decreases for blue colour

Q34- In order to increase the magnifying power of a microscope : A) The objective should have larger focal length and eyepiece should have small focal length B) The focal power of the objective and the eyepiece should be larger C) The objective should have small focal length and the eyepiece should have larger focal length D) The focal length of the objective and the eyepiece should be large

Q35- The focal length of the object of microscope is A) Greater than the focal length of eyepiece B) Less than the focal length of eyepiece C) Equal to the focal length of eyepiece D) Arbitrary

Q36- In which of the given cases do we get very strong reflected rays and very weak refracted rays ? A) Light passing from air to glass B) Light passing from water to glass C) Light passing from glass to diamond D) Light passing from water to air

Q37- Light waves spreading from two sources produce interference only if they are : A) Coherent B) Transverse C) Longitudinal D) None of these

Q38- Which of the given can produce a virtual image larger in size than the object ? A) Convcave lens B) Convex lens C) Convex concave lens D) None of these

Q39- A lens has a power of +0.5D. It is: A) A concave lens of local length 5 m B) A convex lens of focal length 2 m C) A convex lens of focal length 5 m D) A concave lens of focal length 2 m

Q40- On heating a liquid the refractive index generally: A) Increases B) Decreases C) Does not change D) Increases or decreases depending upon rate of heating

Q41- A diverging lens will produce A) Always a virtual image B) Real or virtual image C) Always real image D) None of these

Q42- A hunter wants to shoot a fish whose image can be seen through clear water. It is to be aimed: A) Below the image of fish B) Above the image of fish C) Directly towards the image D) In any direction

Q43- When light enters from a rarer medium to a denser medium: A) Its frequency changes B) Wavelength does not change C) Its wavelength changes D) Both wavelength and frequency change

Q44- Refractive index: A) Depends on the wavelength of light used to measure B) Is actual property of the substance C) Depends on the angle of incidence D) None of these

Q45- An object is approaching a plane mirror at 5 cm/s. A stationary observer sees the image. At what speed will the image appear to approach the stationary observer? A) 20 cm/s B) 10 cm/s C) 15 cm/s D) 5 cm/s

Q46- If a diverging lens is to be used to form an image which is one fourth of the size of the object where must the object be placed? A) 3f B) 4f C) 2f D) F

Q47- Which of the given is NOT paired correctly? A) Solar furnace-concave mirror B) Rear -view mirror-convex mirror C) Magnifying glass -convex lens D) None of these

Q48- A concave lens from the image of an object which is : A) Virtual inverted and diminished B) Virtual upright and diminished C) Virtual inverted and enlarged D) Virtual upright and enlarged

Q49- A man runs towards the plane mirror at 2 m/s. The relative speed of his image with  respect to him will be: A) 4 ms⁻¹ B) 2 ms⁻¹ C) 8 ms⁻¹ D) 10 ms⁻¹

Q50- In order to obtain a magnification of, -0.6 (minus 0.6) with a concave mirror, the object must be placed: A) At the focus B) Between pole and focus C) Between focus and centre of curvature D) Beyond the centre of curvature

 

Q. No.	Ans.	Q. No.	Ans.	Q. No.	Ans.	Q. No.	Ans.	Q. No.	Ans.
1	D	11	D	21	D	31	D	41	B
2	C	12	A	22	C	32	B	42	A
3	D	13	A	23	C	33	C	43	C
4	C	14	D	24	C	34	A	44	A
5	A	15	D	25	D	35	B	45	D
6	B	16	C	26	C	36	D	46	A
7	A	17	D	27	C	37	A	47	D
8	A	18	A	28	D	38	B	48	B
9	A	19	A	29	A	39	B	49	A
10	A	20	A	30	D	40	B	50	D