12th standard physics prepared by: r.rajendran,m.a., m.sc.,m.ed., n.ingaran,m.sc.,m.phil.,m.ed.,...

12TH STANDARDPHYSICS

Prepared by:R.RAJENDRAN,M.A., M.Sc.,M.Ed., N.INGARAN,M.Sc.,M.Phil.,M.Ed.,

Electromagnetic waves and wave optics

1. Electromagnetic waves are discovered by

------------------

a) Planck

b) J.C.Maxwell

c) Newton

d) Huygens

CHOOSE THE CORRECT ANSWER

2. An accelerated charge is a source of ----------

a) electromagnetic radiation

b) heat radiation

c) mechanical waves

d) longitudinal waves


3. Electromagnetic waves are ----------------- in

nature.

a) mechanical waves

b) longitudinal waves

c) transverse

d) none of the above


4. The relation between the velocity of light C,

μ0 and ε0 is given by the relation C = ----------

a) 1 / √μ0 ε0

b) √μ0 ε0

c) √μ0 / ε0

d) √ ε0 / √μ0


5. Hertz produced electromagnetic waves of

frequency ---------------

a) 5 × 109 Hz

b) 5 × 107 Hz

c) 5 × 10-7 Hz

d) 5 × 10-9 Hz


6. Electromagnetic waves cover a wide range

of ----------------

a) directions

b) waves

c) frequencies



7. Atoms and molecules in an electric

discharge tube give -------------- rays.

a) infra-red

b) visible light

c) UV

d) X


8. The wavelength , the frequency and velocity

of light are related by ----------------

a) c = γ λ

b) c = γ / λ

c) c = λ / γ

d) c = γ / λ2


9. The frequency range of AM band is -----------

a) 54 MHz to 890 MHz

b) 88 MHz to 108 MHz

c) 530 kHz to 1710 kHz

d) 88 kHz to 108 kHz


10. The frequency range of FM band is from

--------------

a) 54 MHz to 890 MHz

b) 88 MHz to 108 MHz

c) 530 kHz to 1710 kHz

d) 88 kHz to 108 kHz


11. In Physiotherapy, ------------- lamps are

used.

a) infra-red

b) ordinary

c) UVray

d) X ray


12. The wavelengths of the sodium emission

lines are ----------------- .

a) 5986 Ao and 5890 Ao

b) 5896 Ao and 5980 Ao

c) 5869 Ao and 5890 Ao

d) 5896 Ao and 5890 Ao


13. The ----------- spectrum is used to identify

the gas.

a) continuous

b) band

c) line



14. Incandescent solids, carbon arc lamp etc.

give ------------- spectrum.

a) continuous

b) band

c) line



15. Using ------------- spectra, the molecular

structure of the substance can be studied.

a) continuous

b) band

c) line



16. The example of line absorption spectrum is

------------ spectrum.

a) solar

b) band

c) line



17. The sun’s outer layer is called ----------------

a) photosphere

b) ionosphere

c) thermosphere

d) chromosphere.


18. The type of delayed fluorescence is called

-------------

a) Raman effect

b) Tyndal effect

c) Rayleigh scattering

d) phosphorescence


19. According to corpuscular theory, light

energy is the kinetic energy of the -------------

a) waves

b) light source

c) photons

d) corpuscles


20. Huygens assumed that light waves are

-------------- in nature.

a) longitudinal

b) transverse

c) mechanical

d) stationary


21. The energy of each photon is given by the

equation --------------

a) E = mc2

b) E = h γ

c) E = ma

d) E = mv


22. The scattering of sunlight by the molecules

of the earth’s atmosphere is called ---------

scattering.

a) Raman

b) Tyndal

c) Rayleigh

d) Einstein


23. The scattering of light by the colloidal

particles is called --------------- effect.

a) Raman

b) Tyndal

c) Rayleigh

d) Einstein


24. In industry, ---------------- spectroscopy is

applied to study the properties of the

materials.

a) Raman

b) Tyndal

c) Rayleigh

d) Einstein


25. The locus of the particles having the same

state of vibration is called as ---------------

a) wave

b) corpuscle

c) wavefront

d) photon


26. A linear source of light will give rise to

---------------- wavefront.

a) spherical

b) plane

c) cylindrical

d) elliptical


27. -------------- principle helps us to locate the

position and the shape of the wavefront.

a) Raman

b) Tyndal

c) Rayleigh

d) Huygen


28. In reflection of light, the angle of incidence

= the angle of ------------

a) refraction

b) polarisation

c) reflection

d) diffraction


29. For total internal ----------- to take place,

light must travel from denser medium to rarer

medium.

a) refraction

b) polarisation

c) reflection

d) diffraction


30. The equation of bandwidth of interference

fringes is β = ---------------

a) λD / d

b) λD d

c) λ /D d

d) λd / D


31. An important application of interference in

thin films is the formation of -------------- rings.

a) Raman’s

b) Tyndal’s

c) Rayleigh’s

d) Newton’s


32. The radius of the nth dark ring equation is

------------.

a) r n2 = ( n R λ )2

b) r n = n2 R λ

c) r n = ( n R λ ) ½

d) r n = n R2 λ


33. The amount of bending in diffraction

depends on the ----------------

a) size of the obstacle

b) volume of the obstacle

c) size of the obstacle

d) wavelength of the incident wave.


34. In Fresnel diffraction, the incident

wavefront is either -------------------

a) spherical or ellipse

b) plane or ellipsoid

c) spherical or cylindrical

d) elliptical


35. Using spectrometer, ------------------

diffraction can be observed.

a) Fraunhofer

b) Raman

c) Tyndal

d) Rayleigh


36. The combined width of a slit and a ruling is

called -----------------

a) grating element

b) prism element

c) polaroid element

d) element


37. In a plane diffraction grating, λ = -------------

a) nm / Sin θ

b) Sin θ / nm

c) nm / Sin θ

d) ( nm Sin θ )1/2


38. The phenomenon of ---------------- proves

that light waves are transverse.

a) refraction

b) polarisation

c) reflection

d) diffraction


39. The plane perpendicular to the plane of

vibration is called plane of ------------------

a) refraction

b) polarisation

c) reflection

d) diffraction


40. A device that produces a plane -------------

light is called polariser.

a) polarized

b) reflected

c) refracted

d) diffracted


41. The angle of incidence at which the

reflected beam is completely plane polarised

is called angle of -----------------

a) refraction

b) diffraction

c) reflection

d) polarisation


42. The equation for Brewster’s law is μ = ------

a) sin i p

b) cot i p

c) tan i p

d) cos i p


43. The polarising angle for glass is

-------------------

a) 57. 5

b) 56. 5

c) 32. 5

d) 50. 7


44. The pile of plates uses the polarisation by

---------------------- phenomenon.

a) refraction

b) polarisation

c) reflection

d) diffraction


45. The double refraction phenomenon was

discovered by ------------------

a) Bartholinus

b) Malus

c) Nicol

d) Young


46. Crystals like mica, topaz etc. having two

optic axes are called ------------------

a) uni-axial crystals

b) multi-axial crystals

c) biaxial crystals



47. The refractive index for Canada balsam

cement is -------------- for both the rays.

a) 1.486

b) 1.658

c) 1.550

d) 1.333


48. H polaroids use a thin film of -------------------

a) herapathite crystals

b) polyvinyl alcohol

c) Canada balsam

d) Na Cl


49. Polaroids are used as -----------------------

glasses.

a) moon

b) star

c) planet

d) sun


50. In an EM wave, the electric and the

magnetic field vectors are at ----------- to each

other and to the direction of propagation.

a) 45

b) 90

c) 180

d) 145


51. In an electromagnetic wave

(a) power is equally transferred along the

electric and magnetic fields

(b) power is transmitted in a direction

perpendicular to both the fields

(c) power is transmitted along electric field

(d) power is transmitted along magnetic field


52. Electromagnetic waves are

(a) transverse

(b) longitudinal

(c) may be longitudinal or transverse

(d) neither longitudinal nor transverse


53. Refractive index of glass is 1.5. Time taken

for light to pass through a glass plate of

thickness 10 cm is

(a) 2 × 10–8 s (b) 2 × 10–10 s

(c) 5 × 10–8 s (d) 5 × 10–10 s


54. In an electromagnetic wave the phase

difference between electric field and

magnetic field is

(a) π/4

(b) π/2

(c) π

(d) zero


E

B

55. Atomic spectrum should be

(a) pure line spectrum

(b) emission band spectrum

(c) absorption line spectrum

(d) absorption band spectrum.


56. When a drop of water is introduced between

the glass plate and plano convex lens in

Newton’s rings system, the ring system

(a) contracts

(b) expands

(c) remains same

(d) first expands, then contracts


57. A beam of monochromatic light enters from vacuum into a medium of refractive index μ. The ratio of the wavelengths of the incident and refracted waves is

(a) μ : 1 (b) 1 : μ

(c) μ2 : 1 (d) 1 : μ2


58. If the wavelength of the light is reduced to

one fourth, then the amount of scattering is

(a) increased by 16 times

(b) decreased by 16 times

(c) increased by 256 times

(d) decreased by 256 times


59. In Newton’s ring experiment the radii of the mth and (m + 4)th dark rings are respectively 5 mm and 7 mm. What is the value of m?

(a) 2 (b) 4

(c) 8 (d) 10


60. The path difference between two monochromatic light waves of wavelength 4000 Å is 2 × 10−7 m. The phase difference between them is

(a) π (b) 2π

(c) 3/2π (d) π/2


61. In Young’s experiment, the third bright band for wavelength of light 6000 Å coincides with the fourth bright band for another source in the same arrangement. The wave length of the another source is

(a) 4500 Å (b) 6000 Å

(c) 5000 Å (d) 4000 Å


62. A light of wavelength 6000 Å is incident normally on a grating 0.005 m wide with 2500 lines. Then the maximum order is

(a) 3 (b) 2

(c) 1 (d) 4


63. A diffraction pattern is obtained using a beam of red light. What happens if the red light is replaced by blue light?(a) bands disappear(b) no change(c) diffraction pattern becomes narrower and crowded together(d) diffraction pattern becomes broader and farther apart


64. The refractive index of the medium, for the

polarising angle 60 is

(a) 1.732 (b) 1.414

(c) 1.5 (d) 1.468


THE END

12th standard physics prepared by: r.rajendran,m.a., m.sc.,m.ed., n.ingaran,m.sc.,m.phil.,m.ed.,...

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