Home
Class 12
PHYSICS
Statement-1: When light reflects from th...

Statement-1: When light reflects from the air-glass plate interface, the reflected wave suffers a phase change of `pi`.
Statement-2: The centre of the interference pattern is dark

A

Statement-1 is true, statement-2 is true: Statement-2 is a correct explanation for statement-1

B

statement-1 is false, statement-2 is true

C

Statement-1 is true, Statement-2 is false.

D

statement-1 is true, statement-2 is true and statement-2 is not the correct explanation of statement-1

Text Solution

Verified by Experts

The correct Answer is:
A
`I_(max)=(sqrt(I)+sqrt(4I))^(2)=9I=I_(m)impliesI=(I_(m))/(9)`
`I_(P)=I+4I+2sqrt((I)(4I))cosphi`
`=5I+4Icosphi`
`=I+4I(1+cosphi)`
`=I+8Icos^(2)((phi)/(2))`
`=(I_(m))/(9)(1+8cos^(2)((phi)/(2))`
Promotional Banner

Topper's Solved these Questions

  • WAVE OPTICS

    ALLEN |Exercise Exercise 5 B (Previous Years Questions)|19 Videos

  • WAVE OPTICS

    ALLEN |Exercise Exercise 2 (Previous Year Questions)|7 Videos

  • WAVE OPTICS

    ALLEN |Exercise Exercise 4 B (Conceptual subjective Exercise)|8 Videos

  • UNIT & DIMENSIONS, BASIC MATHS AND VECTOR

    ALLEN |Exercise Exercise (J-A)|7 Videos

Similar Questions

Explore conceptually related problems

When a light wave travels from air to glass,

Statement-1: As light travels from one medium to another, thhe frequency of light doesn't change. Statement-2: Frequency is the characteristic of source.

Statement-1: In YDSE central maxima means the maxima formed with zero optical path difference. It may be formed anywhere on the screen. Statement-2: In an interference pattern, whatever energy disappears at the minimum, appear at the maximum.

A green light is incident from the water to the air - water interface at the critical angle (theta) . Select the correct statement.

Statement- 1 : When an electric fan is switched on in a closed room, the air of the room is cooled. Statement- 2 : When fan is switched on, the speed of the air molecules will increase.

Thin films, including soap bubbles and oil slicks, show patterns of alternating dark and bright regions resulting from interference among the reflected light waves. If two waves are in phase their crest and troughs will coincide. The interference will be constructive and the aplitude of the resultant wave will be greater than the amplitude of either constituent wave. if the two waves are out of phase, the crests of one wave will coincide with the troughs of the other wave. The interference will be destructive and the amplitude of the resultant wave will be less than that of either constituent wave. at the interface between two transparent media some light is reflected and some light is refracted. * When incident light, reaches the surface at point a, some of the light is reflected as ray R_(a) and and some is refracted following the path ab to the back of the film. *At point b some of the light is refracted out of the film and part is reflected back refracted out of the fiml as ray R_(c) . R_(a) and R_(c) are parallel. However, R_(c) has travelled the extra distance within the film of abc. if the angle of incidence is small then abc is approximately twice the film's thickness. if R_(a) and R_(c) are in phase they will undergo constructive interference and the region ac will be bright if R_(a) and R_(c) are out of phase, they will undergo destructive interference. * Refraction at an interface never changes the phase of the wave. * For reflection at the interface between two media 1 and 2, if n_(1)ltn_(2) the reflected wave will change phase by pi . if n_(1)gtn_(2) the reflected wave will not undergo a phase change. for reference n_(air)=1.00 * if the waves are in phase after refection at all interfaces, then the effects of path length in the film are Constructive interference occur when (n= refractive index) 2t=mlamda//n" "m=0,1,2,3... .. Destructive interference occurs when 2t=(m+1//2)lamda//n" "m=0,1,2,3... Q. A 600 nm light is perpendicularly incident on a soap film suspended in air. The film is 1.00 mum thick with n=1.35. Which statement most accurately describes the interference of the light reflected by the two surfaces of the film?

Thin films, including soap bubbles and oil slicks, show patterns of alternating dark and bright regions resulting from interference among the reflected light waves. If two waves are in phase their crest and troughs will coincide. The interference will be constructive and the aplitude of the resultant wave will be greater than the amplitude of either constituent wave. if the two waves are out of phase, the crests of one wave will coincide with the troughs of the other wave. The interference will be destructive and the amplitude of the resultant wave will be less than that of either constituent wave. at the interface between two transparent media some light is reflected and some light is refracted. * When incident light, reaches the surface at point a, some of the light is reflected as ray R_(a) and and some is refracted following the path ab to the back of the film. *At point b some of the light is refracted out of the film and part is reflected back refracted out of the fiml as ray R_(c) . R_(a) and R_(c) are parallel. However, R_(c) has travelled the extra distance within the film of abc. if the angle of incidence is small then abc is approximately twice the film's thickness. if R_(a) and R_(c) are in phase they will undergo constructive interference and the region ac will be bright if R_(a) and R_(c) are out of phase, they will undergo destructive interference. * Refraction at an interface never changes the phase of the wave. * For reflection at the interface between two media 1 and 2, if n_(1)ltn_(2) the reflected wave will change phase by pi . if n_(1)gtn_(2) the reflected wave will not undergo a phase change. for reference n_(air)=1.00 * if the waves are in phase after refection at all interfaces, then the effects of path length in the film are Constructive interference occur when (n= refractive index) 2t=mlamda//n" "m=0,1,2,3... .. Destructive interference occurs when 2t=(m+1//2)lamda//n" "m=0,1,2,3... Q. The average human eye sees colors with wavelengths between 430 nm to 680 nm. For what visible wavelength will a 350 nm thick n=1.35 soap film produce maximum destructive interference?

A green light is incident from the water to the air-water interface at the critical angle ( theta ). Select the correct statement.

In the figure shown S is a point monochromatic light source of frequency 6xx10^(14)Hz .M is a concave mirror of radius of curvature 20 cm and L is a thin converging lens of focal length 3.75 cm AB is the principal axis of M and L. Light reflected from the mirror and refracted from the lens in succession reaches the screen. An interference pattern is obtained on the screen by this arrangement. Q. Distance between two coherent sources whichmakes interference pattern on the screen is

In the figure shown S is a point monochromatic light source of frequency 6xx10^(14)Hz .M is a concave mirror of radius of curvature 20 cm and L is a thin converging lens of focal length 3.75 cm AB is the principal axis of M and L. Light reflected from the mirror and refracted from the lens in succession reaches the screen. An interference pattern is obtained on the screen by this arrangement. Q. Fringe width is

ALLEN -WAVE OPTICS-Exercise 5 A (Previous Years Questions)
  1. To demonstrate the phenomenon of interference, we require two sources ...

    Text Solution

    |

  2. The maximum number of possible interference maxima for slit-separation...

    Text Solution

    |

  3. A Young's double slit experiment uses a monochromatic source. The shap...

    Text Solution

    |

  4. In a Young's double slit experiment the intensity at a point where tha...

    Text Solution

    |

  5. A micture of light, consisting of wavelength 600nm and an unknown wave...

    Text Solution

    |

  6. An intially parallel cyclindrical beam travels in a medium of refracti...

    Text Solution

    |

  7. An intially parallel cyclindrical beam travels in a medium of refracti...

    Text Solution

    |

  8. An intially parallel cyclindrical beam travels in a medium of refracti...

    Text Solution

    |

  9. At two point P and Q on screen in Young's double slit experiment, wave...

    Text Solution

    |

  10. In Young's double slit experiment, the two slits act as coherent sourc...

    Text Solution

    |

  11. Statement-1: When light reflects from the air-glass plate interface, t...

    Text Solution

    |

  12. In Young's double slit experiment, one of the slit is wider than other...

    Text Solution

    |

  13. Two coherent point sources S1 and S2 are separated by a small distance...

    Text Solution

    |

  14. Two beams A and B, of plane polarized light with mutually perpendicula...

    Text Solution

    |

  15. On a hot summer night, the refractive index of air is smallest near th...

    Text Solution

    |

  16. In a Young's double slit experiment with light of wavelength lamda the...

    Text Solution

    |

  17. In Young's double slit experiment, the distance between slits and the ...

    Text Solution

    |