Description : In a Young's double-slit experiment the center of a bright fringe occurs wherever waves from the slits differ in the distance they travel by a multiple of: A. a fourth of a wavelength B. a half a wavelength C. a wavelength D. three-fourths of a wavelength
Last Answer : C. a wavelength
Description : as the order increases, the width of a dark band in diffraction Patterns __________. A. Increases B. Decreases C. Does not change D. becomes infinity
Last Answer : Increases
Description : Fraunhofer diffraction at a Plane Grating What is the meaning of grating element for a diffraction grating? A It is the width of a single slit B. It is the width of the opaque space C. It is the distance between two slits D. It is the width of diffraction grating
Last Answer : C. It is the distance between two slits
Description : .Fringe spacing is defined as the distance between two Consecutive __________. A. Crests B. Bright fringes only C. Dark fringes only D. Bright or dark fringes
Last Answer : A. Crests
Description : Extended source is needed in A. Young's double slit experiment B. Bi prism Experiment C. Newton’s Ring Experiment D. None of them
Last Answer : C. Newton’s Ring Experiment
Description : Coherent light of a single frequency passes through a double slit with a separation d, to produce a pattern on a screen as distance D from the slits. What would cause the separation between adjacent ... d between the slits C. increase the distance D. increase the frequency of the incident light
Last Answer : B. increase the separation d between the slits
Description : When light passes from air into water, the frequency of the light remains the same. What happens to the speed? And the wavelength of light as it crosses the boundary in going from air into ... same Decreases C. Remains the same remains the same D. Decreases Increases E. Decreases Decreases
Last Answer : E. Decreases Decreases
Description : In reflected light the central fringes of Newton's ring is A. dark B. Bright C. Uniform D. Non uniform
Last Answer : A. dark
Description : In Michelson ‘s interferometer 100 fringes cross the field view when the movable mirror is displaced through 0.0248 mm. Calculate the wavelength of monochromatic light used A. 5896 A 0 B.5890 A 0 C.4000 A 0 D. 4890 A 0
Last Answer : B.5890
Description : How the intensity of secondary maxima varies in case of Fraunhofer diffraction pattern for single slit? A. Intensity of secondary maxima decreases on either sides B. Intensity of ... C. Intensity increases and decreases alternately D. Intensity of secondary maxima increases on either sides
Last Answer : A. Intensity of secondary maxima decreases on either sides
Description : Interference pattern is observed in wedge-shaped film and bandwidth is noted. Now the angle of wedge is reduced to zero. What will be the effect on Bandwidth? (a) Bandwidth increases (b) Bandwidth decreases (c) Bands will disappear (d) There will not any effect
Last Answer : (c) Bands will disappear
Description : What is the effect of increasing the number of slits on the intensity of Central maxima of diffraction pattern of a diffraction grating? A. Intensity of central maxima will decrease B. Intensity ... maxima will increase C. There will not be any effect D. Diffraction pattern will disappear
Last Answer : B. Intensity of central maxima will increase
Description : In Newton’s rings experiment, if we reduce the radius of curvature of Plano Convex lens to zero, what will be effect on Newton’s rings? (a)They will become more bright (b)They will become more dark ( c)They will disappear (d) They will be more dense
Last Answer : ( c)They will disappear
Description : In Newton’s rings experiment, if we reduce the radius of curvature of Plano convex lens to zero, what will be effect on Newton’s rings? A. They will become brighter B. They will become darker C. They will disappear D. They will be more dense
Last Answer : C. They will disappear
Description : Whose principle or law states that each point on a wave front may be considered a new wave source? Is it: A. Snell's Law B. Huygens’s Principle C. Young's Law D. Hertz's Law.
Last Answer : B. Huygens’s Principle
Description : A thin film is observed in white light. The color of the film seen at a particular point depends upon (a)Location of observer (b)Width of the source (c) Distance of the source (d) Brightness of the source
Last Answer : (a)Location of observer
Description : In Fresnel diffraction A. source of light is kept at infinite distance from the aperture B. source of light is kept at finite distance from the aperture C. Convex lens used D. aperture width is selected so that it can acts as a point source
Last Answer : B. source of light is kept at finite distance from the aperture
Description : In Fraunhofer diffraction wave front used is __________. A. Spherical B. Circular C. Plane D. Conical 71.In diffraction pattern of monochromatic light the bright bands formed are __________. A. of uniform intensity B. of non-uniform intensity C. of uniform width D. is of different colors
Last Answer : A. of uniform intensity
Description : Interference pattern is observed in wedge-shaped film and bandwidth is noted. Now the angle of wedge is reduced. What will be the effect on bandwidth? (a) Bandwidth increases (b) Bandwidth decreases (c) Bands will disappear (d) There will not any effect
Last Answer : B) BANDWIDTH DECREASES
Description : Interference pattern is observed in wedge-shaped film and bandwidth is noted. Now the thin film is replaced by the film of higher refractive index. What will be the effect on bandwidth? (a) Bandwidth increases (b) Bandwidth decreases (c) Bands will merge (d) There will not any effect
Last Answer : (b) Bandwidth decreases
Description : In interference experiment, monochromatic light is replaced by white light, we will see (a) Uniform illumination of screen (b) Uniform darkness on the screen (c) Equally spaced dark and white bands (d) Few colored bands and then general illumination
Last Answer : (d) Few colored bands and then general illumination
Description : With the increase of pressure, the boiling point of any substance - (1) Increases (2) Decreases (3) Remains Same (4) Becomes zero
Last Answer : (1) Increases Explanation: The temperature stays the same until all the liquid has vaporized. As the temperature of a liquid rises, the pressure of escaping vapor also rises, and at the boiling point ... vapor is equal to that exerted on the liquid by the surrounding air, causing bubbles to form.
Description : With the increase of pressure, the boiling point of any substance – (1) Increases (2) Decreases (3) Remains Same (4) Becomes zero
Description : Newton's rings experiment is performed and radius (or diameter) is calculated. Now Plano-convex lens is replaced with another Plano-convex lens of greater Radius of curvature. What will be effect on radius ( ... ) will increase (c) Radius (or diameter) will decrease (d) There will be no effect
Last Answer : (b) Radius (or diameter) will increase
Description : Newton's rings experiment is performed with air gap between lens and plate. Now that gap is filled with water. What will be effect on radius (or diameter)? (a) Radius (or diameter) will remain ... or diameter) will increase (c) Radius (or diameter) will decrease (d) There will be no effect
Last Answer : (c) Radius (or diameter) will decrease
Description : In Newton's rings experiment, if monochromatic source of light is replaced by another monochromatic source of higher wavelength. What will be the effect on radius (or diameter)? (a) Radius (or ... be no effect (d) Radius (or diameter) will remain constant but there will be more brightness
Description : In interference experiment, by keeping all other parameters constant, if you see the thin film interference from different angles, you will observe (a)Uniform illumination of screen (b) Uniform ... c) Equally spaced dark and white bands (d) Few colored bands and then general illumination
Description : In Newton's ring experiment, the diameter of the 15 th ring was found to be 0.590 and that of the 5 th ring was 0.336 cm. If the radius of Plano convex lens is 100 cm, compute the wavelength of light used. A. 5885 A 0 B. 5880 A o C. 5890 A o D.5850 A
Last Answer : B. 5880 A o
Description : In forward bias, the width of potential barrier __________ (a) Increases (b) decreases (c) remains same (d) no effect
Last Answer : (b) decreases
Description : When two gases are mixed, the entroру (a) Remains constant (b) Decreases (c) Increases (d) Becomes zero
Last Answer : Ans:(c)
Description : When water freezes its density – (1) Decreases (2) Becomes Zero (3) Remains constant (4) Increases
Last Answer : (1) Decreases Explanation: Water at ordinary temperatures contracts and in-creases in density as it is cooled, like most substances. But at about 4°C it reaches a maximum density and then decreases in density as it approaches the freezing point. This is referred to as anomalous property of water.
Description : By increasing the current, the drift velocity A. decreases B. increases C. remains constant D. becomes zero
Last Answer : remains constant
Description : In an oil-lubricated journal bearing, coefficient of friction between the journal and the bearing. [IES-1995] (a) Remains constant at all speeds. (b) is minimum at zero speed and increases ... speed. (d) becomes minimum at an optimum speed and then increases with further increase in speed.
Last Answer : (d) becomes minimum at an optimum speed and then increases with further increase in speed.
Description : As the ball falls towards the ground, its velocity A. increases B. decreases C. remains constant D. becomes zero
Last Answer : increases
Description : When water freezes its density (1) Decreases (2) Becomes Zero (3) Remains constant (4) Increases
Last Answer : Decreases
Description : Fraunhofer diffraction is observed when __________. A. Only screen is placed at finite distance B. source is placed at finite distance C. neither source nor screen is at finite distance D. None of these
Last Answer : D. None of these
Description : Fresnel’s type diffraction is observed when __________. A. Only screen is placed at finite distance B. Only source is placed at finite distance C. Both source and screen are at finite distance D. Neither source nor screen is at finite distance
Last Answer : C. Both source and screen are at finite distance
Description : Diffraction due to circular aperture If a light passes through a small pinhole, and incident on a screen. What will be observed on the screen? A.A sharp bright point of the width equal to ... A bright ring at the centre surrounded by alternate dark and bright rings D. A diffused bright point
Last Answer : C. A bright ring at the centre surrounded by alternate dark and bright rings
Description : The fringe width and the angle of wedge are related to A. β=λ/2θ B. θ =λ/2 β C. β=λ/θ D. λ= β/2θ
Last Answer : A. β=λ/2θ
Description : A slit of width ‘a’ is illuminated by white light. For what value of ‘a’ will the first minimum for red light fall at an angle of 300 wavelength of red light is 6500 A0 A. 1.1 x 10 -3 cm B. 1.4 X 10 -4 cm C. 1.3 X 10 -4 cm D. 1.6 X 10 -4 cm
Last Answer : C. 1.3 X 10 -4 cm
Description : If you look perpendicular at thin film and move yourself away from the film (staying perpendicular to the film), you will notice (a) Reflected light becomes brighter and brighter (b) Reflected ... and darker (c) Reflected light alternates between darker and brighter (d) None of the Above
Last Answer : (c) Reflected light alternates between darker and brighter
Description : .As a wave travels down a spring, the amplitude slowly decreases. Why does this occur? A. The law of conservation of energy does not apply to waves. B. The energy is spread out along the entire ... due to friction as the particles in the spring rub against each other. E. all of the above
Last Answer : D. Some energy is lost due to friction as the particles in the spring rub against each other.
Description : Two sources of light are said to be coherent if __________. A. they produce waves of the same wave length B. they have the same amplitude of vibration C. they produce waves in the medium simultaneously D. they produce waves of the same amplitude
Last Answer : D. they produce waves of the same amplitude
Description : In wedge shaped film the interference pattern has nature (a) Parallel to the end where thickness is non-zero (b) Perpendicular to contact edge (c) Parallel to contact edge (d) Perpendicular to the end where thickness is non-zero
Last Answer : (c) Parallel to contact edge
Description : A wedge shaped thin has (a) Non-uniform thickness (b) Zero thickness at one end and it increasing towards other end (c) Zero thickness at both ends (d) Thickness increase and decrease alternately
Last Answer : b) Zero thickness at one end and it increasing towards other end
Description : In Fraunhofer diffraction pattern for single slit, a central maximum is obtained when angle of diffraction q is equal to zero. What it actually indicates? A. All the diffracted rays are parallel and focused ... are diffracted by the slit in all the directions D. The rays are reflected by the slit
Last Answer : A. All the diffracted rays are parallel and focused by slit at a single point on screen
Description : Why in Newton’s rings the center spot is always dark? A. The thickness of the film is zero at center B. The path difference between incident ray and reflected ray is ½wavelength C. The incident ray and reflected ray undergo destructive interference D. All of above
Last Answer : D. All of above
Description : A wedge shaped thin has A. Non-uniform thickness B. Zero thickness at one end and it increasing towards other end C. Zero thickness at both ends D. Thickness increase and decrease alternately
Last Answer : B. Zero thickness at one end and it increasing towards other end
Description : Which of the following condition is essential for observing Fraunhofer diffraction? A. Source must be close to slit and screen should be at infinite distance B. Both source and screen must be close to ... infinity and screen should be close to the slit D. Both source and screen must be at infinity
Last Answer : D. Both source and screen must be at infinity
Description : here are two types of diffraction Fresnel and __________. A. Michelson B. De Broglie C. Fraunhofer D. Huygens
Last Answer : C. Fraunhofer