12583 + Mcqs in Physics Page 220 McqOptions

10951.	A person trying to lose weight by burning fat lifts a mass of 10 kg up to a height of 1 m 1000 times. Assume that the potential energy lost each time he lowers the mass is dissipated. How much fat will he use up considering the work done only when the weight is lifted up? Fat supplies \[3.8\times {{10}^{7}}\] J of energy per kg which is converted to mechanical energy with a 20% efficiency rate. Take \[g=9.8m{{s}^{-2}}\].
A.	\[2.45\times {{10}^{-3}}kg\]
B.	\[6.45\times {{10}^{-3}}kg\]
C.	\[9.89\times {{10}^{-3}}kg\]
D.	\[12.89\times {{10}^{-3}}kg\]
Answer» E.

Discussion

10952.	Assertion : Work done by or against gravitational force in moving a body from one point to another is independent of the actual path followed between the two points. Reason : Gravitational forces are conservative forces.
A.	If both assertion and reason are true and the reason is the correct explanation of the assertion.
B.	If both assertion and reason are true but reason is not the correct explanation of the assertion.
C.	If assertion is true but reason is false.
D.	If the assertion and reason both are false.
Answer» B. If both assertion and reason are true but reason is not the correct explanation of the assertion.

Discussion

10953.	A body of mass m having an initial velocity v, makes head on collision with a stationary body of mass M. After the collision, the body of mass m comes to rest and only the body having mass M moves. This will happen only when [MP PMT 1995]
A.	\[m>>M\]
B.	\[m<<M\]
C.	\[m=M\]
D.	\[m=\frac{1}{2}M\]
Answer» D. \[m=\frac{1}{2}M\]

Discussion

10954.	Two identical blocks A and B, each of mass 'm' resting on smooth floor are connected by a light spring of natural length L and spring constant K, with the spring at its natural length. A third identical block 'C' (mass m) moving with a speed v along the line joining A and B collides with A. the maximum compression in the spring is [EAMCET 2003]
A.	\[v\sqrt{\frac{m}{2k}}\]
B.	\[m\sqrt{\frac{v}{2k}}\]
C.	\[\sqrt{\frac{mv}{k}}\]
D.	\[\frac{mv}{2k}\]
Answer» B. \[m\sqrt{\frac{v}{2k}}\]

Discussion

10955.	The ratio of intensities of two waves is 9 : 1. They are producing interference. The ratio of maximum and minimum intensities will be [MNR 1987 MP PET 1999; AMU (Engg.) 1999; AIIMS 2000]
A.	10 : 8
B.	9 : 1
C.	4 : 1
D.	2 : 1
Answer» D. 2 : 1

Discussion

10956.	A wave can transmit ...... from one place to another [CPMT 1984]
A.	Energy
B.	Amplitude
C.	Wavelength
D.	Matter
Answer» B. Amplitude

Discussion

10957.	If the ratio of intensities of two waves is 1 : 25, then the ratio of their amplitudes will be [CPMT 1984]
A.	1 : 25
B.	5 : 1
C.	26 : 24
D.	1 : 5
Answer» E.

Discussion

10958.	Two sources of waves are called coherent if [NCERT 1984; MNR 1995; RPMT 1996, 97; CPMT 1997; UPSEAT 1995, 2000; Orissa JEE 2002; RPET 2003; MP PMT 1996, 2004]
A.	Both have the same amplitude of vibrations
B.	Both produce waves of the same wavelength
C.	Both produce waves of the same wavelength having constant phase difference
D.	Both produce waves having the same velocity
Answer» D. Both produce waves having the same velocity

Discussion

10959.	If L is the coherence length and c the velocity of light, the coherent time is [MP PMT 1996]
A.	cL
B.	\[\frac{L}{c}\]
C.	\[\frac{c}{L}\]
D.	\[\frac{1}{Lc}\]
Answer» C. \[\frac{c}{L}\]

Discussion

10960.	If the amplitude ratio of two sources producing interference is 3 : 5, the ratio of intensities at maxima and minima is [MP PMT 1996]
A.	25 : 16
B.	5 : 3
C.	16 : 1
D.	25 : 9
Answer» D. 25 : 9

Discussion

10961.	Colours of thin films result from [CPMT 1972, 83, 96; RPMT 1997; DCE 2002; AIIMS 2005] or On a rainy day, a small oil film on water show brilliant colours. This is due to [MP PET 2004]
A.	Dispersion of light
B.	Interference of light
C.	Absorption of light
D.	Scattering of light
Answer» C. Absorption of light

Discussion

10962.	For constructive interference to take place between two monochromatic light waves of wavelength l, the path difference should be [MNR 1992; UPSEAT 2001]
A.	\[(2n-1)\frac{\lambda }{4}\]
B.	\[(2n-1)\frac{\lambda }{2}\]
C.	\[n\lambda \]
D.	\[(2n+1)\frac{\lambda }{2}\]
Answer» D. \[(2n+1)\frac{\lambda }{2}\]

Discussion

10963.	Soap bubble appears coloured due to the phenomenon of [AFMC 1995, 97; RPET 1997; CBSE PMT 1999; Pb PET 2001]
A.	Interference
B.	Diffraction
C.	Dispersion
D.	Reflection
Answer» B. Diffraction

Discussion

10964.	Evidence for the wave nature of light cannot be obtained from [MP PET 1996]
A.	Reflection
B.	Doppler effect
C.	Interference
D.	Diffraction
Answer» B. Doppler effect

Discussion

10965.	Two light sources are said to be coherent if they are obtained from [MP PET 1996]
A.	Two independent point sources emitting light of the same wavelength
B.	A single point source
C.	A wide source
D.	Two ordinary bulbs emitting light of different wavelengths
Answer» C. A wide source

Discussion

10966.	Wavelength of light of frequency 100Hz [CBSE PMT 1999]
A.	\[2\times {{10}^{6}}m\]
B.	\[3\times {{10}^{6}}m\]
C.	\[4\times {{10}^{6}}m\]
D.	\[5\times {{10}^{6}}m\]
Answer» C. \[4\times {{10}^{6}}m\]

Discussion

10967.	The ratio of intensities of two waves are given by 4 : 1. The ratio of the amplitudes of the two waves is [CBSE PMT 1993]
A.	2 : 1
B.	1 : 2
C.	4 : 1
D.	1 : 4
Answer» B. 1 : 2

Discussion

10968.	For the sustained interference of light, the necessary condition is that the two sources should [DPMT 1996; RPMT 1998, 2003]
A.	Have constant phase difference
B.	Be narrow
C.	Be close to each other
D.	Of same amplitude
Answer» B. Be narrow

Discussion

10969.	If the ratio of amplitude of two waves is 4 : 3, then the ratio of maximum and minimum intensity is [AFMC 1997]
A.	16 : 18
B.	18 : 16
C.	49 : 1
D.	94 : 1
Answer» D. 94 : 1

Discussion

10970.	The dual nature of light is exhibited by [KCET 1999; AIIMS 2001; BHU 2001; MH CET 2003; BCECE 2004]
A.	Photoelectric effect
B.	Refraction and interference
C.	Diffraction and reflection
D.	Diffraction and photoelectric effect
Answer» E.

Discussion

10971.	Two beams of light having intensities I and 4I interfere to produce a fringe pattern on a screen. The phase difference between the beams is \[\frac{\pi }{2}\] at point A and p at point B. Then the difference between the resultant intensities at A and B is [IIT JEE (Screening) 2001]
A.	2I
B.	4I
C.	5I
D.	7I
Answer» C. 5I

Discussion

10972.	Coherent sources are those sources for which [RPET 2001]
A.	Phase difference remain constant
B.	Frequency remains constant
C.	Both phase difference and frequency remains constant
D.	None of these
Answer» D. None of these

Discussion

10973.	Two coherent sources of light can be obtained by [MH CET 2001]
A.	Two different lamps
B.	Two different lamps but of the same power
C.	Two different lamps of same power and having the same colour
D.	None of the above
Answer» E.

Discussion

10974.	By Huygen's wave theory of light, we cannot explain the phenomenon of [CPMT 1989; AFMC 1993, 99; MP PET 1995, 2003; RPMT 2003; BCECE 2003; Pb PMT 2004]
A.	Interference
B.	Diffraction
C.	Photoelectric effect
D.	Polarisation
Answer» D. Polarisation

Discussion

10975.	The phenomenon of interference is shown by [MNR 1994; MP PMT 1997; AIIMS 1999, 2000; JIPMER 2000; UPSEAT 1994, 2000]
A.	Longitudinal mechanical waves only
B.	Transverse mechanical waves only
C.	Electromagnetic waves only
D.	All the above types of waves
Answer» E.

Discussion

10976.	In the interference pattern, energy is
A.	Created at the position of maxima
B.	Destroyed at the position of minima
C.	Conserved but is redistributed
D.	None of the above
Answer» D. None of the above

Discussion

10977.	Young's experiment establishes that [CPMT 1972; MP PET 1994, 98; MP PMT 1998]
A.	Light consists of waves
B.	Light consists of particles
C.	Light consists of neither particles nor waves
D.	Light consists of both particles and waves
Answer» B. Light consists of particles

Discussion

10978.	The maximum intensity of fringes in Young's experiment is I. If one of the slit is closed, then the intensity at that place becomes Io. Which of the following relation is true? [NCERT 1982; MP PMT 1994, 99; BHU 1998; RPMT 1996; RPET 1999; AMU (Engg.) 1999]
A.	I = Io
B.	I = 2Io
C.	I = 4Io
D.	There is no relation between I and Io
Answer» D. There is no relation between I and Io

Discussion

10979.	In the Young's double slit experiment, the ratio of intensities of bright and dark fringes is 9. This means that [IIT 1982]
A.	The intensities of individual sources are 5 and 4 units respectively
B.	The intensities of individual sources are 4 and 1 units respectively
C.	The ratio of their amplitudes is 3
D.	The ratio of their amplitudes is 2
Answer» C. The ratio of their amplitudes is 3

Discussion

10980.	In Young's double slit experiment, if L is the distance between the slits and the screen upon which interference pattern is observed, x is the average distance between the adjacent fringes and d being the slit separation. The wavelength of light is given by [MP PET 1993]
A.	\[\frac{xd}{L}\]
B.	\[\frac{xL}{d}\]
C.	\[\frac{Ld}{x}\]
D.	\[\frac{1}{Ldx}\]
Answer» B. \[\frac{xL}{d}\]

Discussion

10981.	An oil flowing on water seems coloured due to interference. For observing this effect, the approximate thickness of the oil film should be [DPET 1987; JIPMER 1997; RPMT 2002, 04]
A.	\[100\,\,{AA}\]
B.	\[10000\,\,{AA}\]
C.	1 mm
D.	1 cm
Answer» C. 1 mm

Discussion

10982.	In a Young's double slit experiment, the central point on the screen is [MP PMT 1996]
A.	Bright
B.	Dark
C.	First bright and then dark
D.	First dark and then bright
Answer» B. Dark

Discussion

10983.	In a Young's double slit experiment, the fringe width is found to be 0.4 mm. If the whole apparatus is immersed in water of refractive index 4/3 without disturbing the geometrical arrangement, the new fringe width will be [CBSE PMT 1990]
A.	0.30 mm
B.	0.40 mm
C.	0.53 mm
D.	450 micron
Answer» B. 0.40 mm

Discussion

10984.	Young's experiment is performed in air and then performed in water, the fringe width [CPMT 1990; MP PMT 1994; RPMT 1997; Kerala PMT 2004]
A.	Will remain same
B.	Will decrease
C.	Will increase
D.	Will be infinite
Answer» C. Will increase

Discussion

10985.	In double slits experiment, for light of which colour the fringe width will be minimum [MP PMT 1994]
A.	Violet
B.	Red
C.	Green
D.	Yellow
Answer» B. Red

Discussion

10986.	In Young's experiment, light of wavelength 4000 Å is used to produce bright fringes of width 0.6 mm, at a distance of 2 meters. If the whole apparatus is dipped in a liquid of refractive index 1.5, then fringe width will be [MP PMT 1994]
A.	0.2 mm
B.	0.3 mm
C.	0.4 mm
D.	1.2 mm
Answer» D. 1.2 mm

Discussion

10987.	In Young's double slit experiment when wavelength used is 6000 Å and the screen is 40 cm from the slits, the fringes are 0.012 cm wide. What is the distance between the slits [MP PMT 1995; Pb PET 2002]
A.	0.024 cm
B.	2.4 cm
C.	0.24 cm
D.	0.2 cm
Answer» E.

Discussion

10988.	In two separate set - ups of the Young's double slit experiment, fringes of equal width are observed when lights of wavelengths in the ratio 1 : 2 are used. If the ratio of the slit separation in the two cases is 2 : 1, the ratio of the distances between the plane of the slits and the screen in the two set - ups is [KCET 1996]
A.	4 : 1
B.	1 : 1
C.	1 : 4
D.	2 : 1
Answer» B. 1 : 1

Discussion

10989.	In an interference experiment, the spacing between successive maxima or minima is [MP PET 1996]
A.	\[\frac{\lambda d}{D}\]
B.	\[\frac{\lambda D}{d}\]
C.	\[\frac{dD}{\lambda }\]
D.	\[\frac{\lambda d}{4D}\] (Where the symbols have their usual meanings)
Answer» C. \[\frac{dD}{\lambda }\]

Discussion

10990.	In a biprism experiment, by using light of wavelength 5000 Å, 5 mm wide fringes are obtained on a screen 1.0 m away from the coherent sources. The separation between the two coherent sources is [MP PMT/PET 1998]
A.	1.0 mm
B.	0.1 mm
C.	0.05 mm
D.	0.01 mm
Answer» C. 0.05 mm

Discussion

10991.	The slits in a Young's double slit experiment have equal widths and the source is placed symmetrically relative to the slits. The intensity at the central fringes is I0. If one of the slits is closed, the intensity at this point will be [MP PMT 1999; Orissa JEE 2004; Kerala PET 2005]
A.	I0
B.	I0 / 4
C.	I0 / 2
D.	4I0
Answer» C. I0 / 2

Discussion

10992.	A thin mica sheet of thickness \[2\times {{10}^{-6}}m\]and refractive index \[(\mu =1.5)\] is introduced in the path of the first wave. The wavelength of the wave used is 5000 Å. The central bright maximum will shift [CPMT 1999]
A.	2 fringes upward
B.	2 fringes downward
C.	10 fringes upward
D.	None of these
Answer» B. 2 fringes downward

Discussion

10993.	In Young's double slit experiment, angular width of fringes is 0.20o for sodium light of wavelength 5890 Å. If complete system is dipped in water, then angular width of fringes becomes [RPET 1997]
A.	0.11o
B.	0.15o
C.	0.22o
D.	0.30o
Answer» C. 0.22o

Discussion

10994.	In Young's double slit experiment, 62 fringes are seen in visible region for sodium light of wavelength 5893 Å. If violet light of wavelength 4358 Å is used in place of sodium light, then number of fringes seen will be [RPET 1997]
A.	54
B.	64
C.	74
D.	84
Answer» E.

Discussion

10995.	In Young's double slit experiment, the distance between the slits is 1 mm and that between slit and screen is 1 meter and 10th fringe is 5 mm away from the central bright fringe, then wavelength of light used will be [RPMT 1997]
A.	\[5000\,\,{AA}\]
B.	\[6000\,\,{AA}\]
C.	\[7000\,\,{AA}\]
D.	\[8000\,\,{AA}\]
Answer» B. \[6000\,\,{AA}\]

Discussion

10996.	In Young's double slit experiment using sodium light\[(l=5898\,\,{AA})\], 92 fringes are seen. If given colour\[(l=5461\,\,{AA})\]is used, how many fringes will be seen [CPMT 1989; RPET 1996; JIPMER 2001, 02]
A.	62
B.	67
C.	85
D.	99
Answer» E.

Discussion

10997.	If a torch is used in place of monochromatic light in Young?s experiment what will happens [MH CET 1999; KCET 1999]
A.	Fringe will appear for a moment then it will disappear
B.	Fringes will occur as from monochromatic light
C.	Only bright fringes will appear
D.	No fringes will appear
Answer» E.

Discussion

10998.	When a thin metal plate is placed in the path of one of the interfering beams of light [KCET 1999]
A.	Fringe width increases
B.	Fringes disappear
C.	Fringes become brighter
D.	Fringes becomes blurred
Answer» C. Fringes become brighter

Discussion

10999.	In Young's double slit interference experiment, the slit separation is made 3 fold. The fringe width becomes [CPMT 1982, 89]
A.	1/3 times
B.	1/9 times
C.	3 times
D.	9 times
Answer» B. 1/9 times

Discussion

11000.	In a certain double slit experimental arrangement interference fringes of width 1.0 mm each are observed when light of wavelength 5000 Å is used. Keeping the set up unaltered, if the source is replaced by another source of wavelength 6000 Å, the fringe width will be [CPMT 1988]
A.	0.5 mm
B.	1.0 mm
C.	1.2 mm
D.	1.5 mm
Answer» D. 1.5 mm

Discussion

Explore topic-wise MCQs in Joint Entrance Exam - Main (JEE Main).

Assertion : Work done by or against gravitational force in moving a body from one point to another is independent of the actual path followed between the two points. Reason : Gravitational forces are conservative forces.

A body of mass m having an initial velocity v, makes head on collision with a stationary body of mass M. After the collision, the body of mass m comes to rest and only the body having mass M moves. This will happen only when [MP PMT 1995]

The ratio of intensities of two waves is 9 : 1. They are producing interference. The ratio of maximum and minimum intensities will be [MNR 1987 MP PET 1999; AMU (Engg.) 1999; AIIMS 2000]

A wave can transmit ...... from one place to another [CPMT 1984]

If the ratio of intensities of two waves is 1 : 25, then the ratio of their amplitudes will be [CPMT 1984]

Two sources of waves are called coherent if [NCERT 1984; MNR 1995; RPMT 1996, 97; CPMT 1997; UPSEAT 1995, 2000; Orissa JEE 2002; RPET 2003; MP PMT 1996, 2004]

If L is the coherence length and c the velocity of light, the coherent time is [MP PMT 1996]

If the amplitude ratio of two sources producing interference is 3 : 5, the ratio of intensities at maxima and minima is [MP PMT 1996]

Colours of thin films result from [CPMT 1972, 83, 96; RPMT 1997; DCE 2002; AIIMS 2005] or On a rainy day, a small oil film on water show brilliant colours. This is due to [MP PET 2004]

For constructive interference to take place between two monochromatic light waves of wavelength l, the path difference should be [MNR 1992; UPSEAT 2001]

Soap bubble appears coloured due to the phenomenon of [AFMC 1995, 97; RPET 1997; CBSE PMT 1999; Pb PET 2001]

Evidence for the wave nature of light cannot be obtained from [MP PET 1996]

Two light sources are said to be coherent if they are obtained from [MP PET 1996]

Wavelength of light of frequency 100Hz [CBSE PMT 1999]

The ratio of intensities of two waves are given by 4 : 1. The ratio of the amplitudes of the two waves is [CBSE PMT 1993]

For the sustained interference of light, the necessary condition is that the two sources should [DPMT 1996; RPMT 1998, 2003]

If the ratio of amplitude of two waves is 4 : 3, then the ratio of maximum and minimum intensity is [AFMC 1997]

The dual nature of light is exhibited by [KCET 1999; AIIMS 2001; BHU 2001; MH CET 2003; BCECE 2004]

Two beams of light having intensities I and 4I interfere to produce a fringe pattern on a screen. The phase difference between the beams is \[\frac{\pi }{2}\] at point A and p at point B. Then the difference between the resultant intensities at A and B is [IIT JEE (Screening) 2001]

Coherent sources are those sources for which [RPET 2001]

Two coherent sources of light can be obtained by [MH CET 2001]

By Huygen's wave theory of light, we cannot explain the phenomenon of [CPMT 1989; AFMC 1993, 99; MP PET 1995, 2003; RPMT 2003; BCECE 2003; Pb PMT 2004]

The phenomenon of interference is shown by [MNR 1994; MP PMT 1997; AIIMS 1999, 2000; JIPMER 2000; UPSEAT 1994, 2000]

In the interference pattern, energy is

Young's experiment establishes that [CPMT 1972; MP PET 1994, 98; MP PMT 1998]

The maximum intensity of fringes in Young's experiment is I. If one of the slit is closed, then the intensity at that place becomes Io. Which of the following relation is true? [NCERT 1982; MP PMT 1994, 99; BHU 1998; RPMT 1996; RPET 1999; AMU (Engg.) 1999]

In the Young's double slit experiment, the ratio of intensities of bright and dark fringes is 9. This means that [IIT 1982]

In Young's double slit experiment, if L is the distance between the slits and the screen upon which interference pattern is observed, x is the average distance between the adjacent fringes and d being the slit separation. The wavelength of light is given by [MP PET 1993]

An oil flowing on water seems coloured due to interference. For observing this effect, the approximate thickness of the oil film should be [DPET 1987; JIPMER 1997; RPMT 2002, 04]

In a Young's double slit experiment, the central point on the screen is [MP PMT 1996]

In a Young's double slit experiment, the fringe width is found to be 0.4 mm. If the whole apparatus is immersed in water of refractive index 4/3 without disturbing the geometrical arrangement, the new fringe width will be [CBSE PMT 1990]

Young's experiment is performed in air and then performed in water, the fringe width [CPMT 1990; MP PMT 1994; RPMT 1997; Kerala PMT 2004]

In double slits experiment, for light of which colour the fringe width will be minimum [MP PMT 1994]

In Young's experiment, light of wavelength 4000 Å is used to produce bright fringes of width 0.6 mm, at a distance of 2 meters. If the whole apparatus is dipped in a liquid of refractive index 1.5, then fringe width will be [MP PMT 1994]

In Young's double slit experiment when wavelength used is 6000 Å and the screen is 40 cm from the slits, the fringes are 0.012 cm wide. What is the distance between the slits [MP PMT 1995; Pb PET 2002]

In an interference experiment, the spacing between successive maxima or minima is [MP PET 1996]

In a biprism experiment, by using light of wavelength 5000 Å, 5 mm wide fringes are obtained on a screen 1.0 m away from the coherent sources. The separation between the two coherent sources is [MP PMT/PET 1998]

The slits in a Young's double slit experiment have equal widths and the source is placed symmetrically relative to the slits. The intensity at the central fringes is I0. If one of the slits is closed, the intensity at this point will be [MP PMT 1999; Orissa JEE 2004; Kerala PET 2005]

A thin mica sheet of thickness \[2\times {{10}^{-6}}m\]and refractive index \[(\mu =1.5)\] is introduced in the path of the first wave. The wavelength of the wave used is 5000 Å. The central bright maximum will shift [CPMT 1999]

In Young's double slit experiment, angular width of fringes is 0.20o for sodium light of wavelength 5890 Å. If complete system is dipped in water, then angular width of fringes becomes [RPET 1997]

In Young's double slit experiment, 62 fringes are seen in visible region for sodium light of wavelength 5893 Å. If violet light of wavelength 4358 Å is used in place of sodium light, then number of fringes seen will be [RPET 1997]

In Young's double slit experiment, the distance between the slits is 1 mm and that between slit and screen is 1 meter and 10th fringe is 5 mm away from the central bright fringe, then wavelength of light used will be [RPMT 1997]

In Young's double slit experiment using sodium light\[(l=5898\,\,{AA})\], 92 fringes are seen. If given colour\[(l=5461\,\,{AA})\]is used, how many fringes will be seen [CPMT 1989; RPET 1996; JIPMER 2001, 02]

If a torch is used in place of monochromatic light in Young?s experiment what will happens [MH CET 1999; KCET 1999]

When a thin metal plate is placed in the path of one of the interfering beams of light [KCET 1999]

In Young's double slit interference experiment, the slit separation is made 3 fold. The fringe width becomes [CPMT 1982, 89]

In a certain double slit experimental arrangement interference fringes of width 1.0 mm each are observed when light of wavelength 5000 Å is used. Keeping the set up unaltered, if the source is replaced by another source of wavelength 6000 Å, the fringe width will be [CPMT 1988]