Practice Test


1) When a ray of monochromatic light is incident normally on glass surface then refracted ray


2) In periscopes, totally reflecting prisms are used which turns the ray through


3) When a light is incident at one end of the fibre at a small angle, then refracted light falls on the wall of the fibre at an angle


4) When a monochromatic ray of light travels from an optically denser medium to optically rarer medium then critical angle is the angle of incidence for which angle of refraction is


5) The refractivity of the material of the prism is given by


6) To observe any rainbow the altitude of sun or the angle made by the sun with the horizontal should be


7) Angular width of primary rainbow is


8) The average angle of inclination of the primary rainbow with the axis is


9) The average angle of inclination of the secondary rainbow with the axis is


10) A yellow light travels from rarer medium to denser medium. At the value of critical angle, the ray will


11) The distance travelled by a ray of light in two media, in the same time are in the ratio 2:3. The ratio of refractive index of the first medium to second medium is


12) The refractive index of air with respect to glass is 2/3. The refractive index of diamond with respect to air is 12/5. Then, the refraction index of glass with respect to diamond will be


13) Light consists of


14) If medium changes


15) The colour of light is determined by


16) LASER is a


17) A wave of light of ___ wave length is called monochromatic light.


18) When a ray of monochromatic light is incident obliquely on the interface of two media,


19) When a monochromatic light passes from one transparent medium into another, its direction changes ( except for normal incidence). This phenomenon is known as


20) The angle made by the incident ray with the reflecting surface or interface is called as


21) The relation between angle of incidence and angle of refraction was discovered by


22) The absolute refractive index of any medium is always


23) When a ray of monochromatic light enters from rarer medium to denser medium obliquely, the angle of incidence i and angle of refraction r is related as


24) The value of refractive index of ________ is highest.


25) The velocity of light is different in different media. This is the cause of refraction according to


26) The velocity of light is maximum in


27) If the ray of light travels from medium 1 to medium 2 and ultimately reverses its path then the phenomenon is


28) The bottom of a swimming pool appears to be less deep than actual because of


29) When light travels from one medium to another, which are separated by sharp boundary, the quantity which does NOT change is


30) The ray of light travelling from an optically denser medium to optically rarer medium bends


31) Which of the following is NOT a property of light ?


32) 'Mirage' is a phenomenon due to


33) Brilliance of diamond is due to


34) Which of the following is a CORRECT statement ?


35) As ' i ' increases, intensity of


36) Critical angle of light passing from glass to air is minimum for


37) The angle of incidence corresponding to which angle of refraction is a right angle is called as


38) An endoscope is used by a physician to view the internal parts of a body organ. It is based on the principle of


39) The separation of white light into its constituent colours after passing through a prism is called as ______ of light.


40) In telecommunications ___________ is used to carry sound signals coded in light signals, over large distance.


41) The light entering into the fibre suffers


42) The optical fibre acts as a


43) Optical fibre consists of large number of


44) When white light passes through prism then constituent colours are obtained because


45) When white light passes through prism, the angle of deviation is


46) As the refractive index of the material of prism for different colours increases their corresponding wavelengths


47) A prism splits a beam of white light into its constituent colours. This is so because


48) A ______ shaped triangular transparent block having three rectangular planes and two traingular planes is called a prism.


49) The angle between the two planes rectangular refracting surface is called


50) The rectangular face opposite to the refracting edge is called


51) The angle between incident ray and ______ ray is called angle of deviation.


52) A prism is placed in water. The angle of minimum deviation


53) While deriving prism formula, angle of deviation is minimum if


54) Thin prism has small


55) A glass prism placed in a homogenous transparent medium will deviate an incident ray


56) Angular dispersion depends upon


57) The refractive index of the prism for violet colour is 1.7 and that for red is 1.65. Then dispersive power of the material of prism is


58) Dispersive power of prism depends on


59) A beam of light compose of red and green ray is incident obliquely at a point on the face of rectangular glass slab. When coming out on the opposite parallel face, the red and green ray emerge from


60) A narrow beam of white light passes through glass slab having parallel faces. Then,


61) When a glass prism is placed inside water, its dispersive power


62) In optical instruments, to minimise the effect of dispersion and obtain clear and well defined images,


63) The arrangement of dispersion without deviation is used in


64) The complete circle of rainbow can be seen when


65) The rainbow is formed due to


66) The primary rainbow is due to _______ total internal reflection inside droplet and two refractions.


67) The secondary rainbow is due to ________ total internal reflection inside droplet.


68) In case of secondary rainbow, ______ colour is at the top.


69) The straight line joining the sun and the observer along which centre of both the primary and secondary rainbow lies is called


70) The first explanation of rainbow was given by


71) One cannot see through fog, because


72) The intensity of scattered light, according to Rayleigh's law is


73) Rayleigh's law of scattering assumes


74) The sky will appear red instead of blue if


75) Beyond earth's atmosphere, the sky will look


76) The sky appears blue because


77) Just after the sunrise, the sun is very close to horizon, so the sunlight has to travel


78) The sun appears reddish or orange reddish at the


79) Our eyes are more sensitive to blue as compared to


80) The angle between incident ray and reflected ray or refracted ray is called


81) Blue colour of sky is due to phenomenon of


82) Just after the sunrise, the sky appears reddish because


83) When a ray of light passes from air to denser medium, its speed is reduced by 30%. What is the refractive index of the medium ?


84) An object immersed in a fluid becomes invisible, if it


85) Sir C.V. Raman was awarded nobel prize for his work concerned with which of the following phenomenon of radiation ?


86) A person swimming at the bottom of swimming pool looks upto the diving board. The board


87) Which of the following is the CORRECT statement.


88) For visible light the wave length ranges from


89) Dispersion of light is shown in the following diagram, select the CORRECT one.


90) The principle used in optical fibre is


91) The net angular dispersion without deviation is equal to