12583 + Mcqs in Physics Page 17 McqOptions

801.	Image formed by a convex mirror is [MP PET 1993]
A.	Virtual
B.	Real
C.	Enlarged
D.	Inverted
Answer» B. Real

Discussion

802.	A convex mirror is used to form the image of an object. Then which of the following statements is wrong [CPMT 1973]
A.	The image lies between the pole and the focus
B.	The image is diminished in size
C.	The image is erect
D.	The image is real
Answer» E.

Discussion

803.	In a concave mirror experiment, an object is placed at a distance \[{{x}_{1}}\] from the focus and the image is formed at a distance \[{{x}_{2}}\] from the focus. The focal length of the mirror would be [MP PET 1997]
A.	\[{{x}_{1}}{{x}_{2}}\]
B.	\[\sqrt{{{x}_{1}}{{x}_{2}}}\]
C.	\[\frac{{{x}_{1}}+{{x}_{2}}}{2}\]
D.	\[\sqrt{\frac{{{x}_{1}}}{{{x}_{2}}}}\]
Answer» C. \[\frac{{{x}_{1}}+{{x}_{2}}}{2}\]

Discussion

804.	A force of 200 N is applied at one end of a wire of length 2 m and having area of cross-section \[{{10}^{-2}}\,c{{m}^{2}}\]. The other end of the wire is rigidly fixed. If coefficient of linear expansion of the wire \[\alpha =8\times {{10}^{-6}}/{}^\circ C\] and Young's modulus \[Y=2.2\times {{10}^{11}}\,N/{{m}^{2}}\] and its temperature is increased by 5°C, then the increase in the tension of the wire will be
A.	4.2 N
B.	4.4 N
C.	2.4 N
D.	8.8 N
Answer» E.

Discussion

805.	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

806.	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

807.	In double slit experiment, the angular width of the fringes is 0.20o for the sodium light (l =\[5890\,{AA}\]). In order to increase the angular width of the fringes by 10%, the necessary change in the wavelength is [MP PMT 1997]
A.	Increase of\[589\,\,{AA}\]
B.	Decrease of\[589\,\,{AA}\]
C.	Increase of\[6479\,\,{AA}\]
D.	Zero
Answer» B. Decrease of\[589\,\,{AA}\]

Discussion

808.	Interference was observed in interference chamber when air was present, now the chamber is evacuated and if the same light is used, a careful observer will see [CBSE PMT 1993; DPMT 2000; BHU 2002]
A.	No interference
B.	Interference with bright bands
C.	Interference with dark bands
D.	Interference in which width of the fringe will be slightly increased
Answer» E.

Discussion

809.	The addition of antimony atoms to a sample of intrinsic germanium transforms it to a material which is [AMU 1995]
A.	Superconductor
B.	An insulator
C.	N-type semiconductor
D.	P-type semiconductor
Answer» D. P-type semiconductor

Discussion

810.	Assertion : In javelin throw, the athlete throws the projectile at an angle slightly more than 45°. Reason : The maximum range does not depends upon angle of projection.
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.
E.	If assertion is false but reason is true.
Answer» E. If assertion is false but reason is true.

Discussion

811.	An object is located in a fixed position in front of a screen. Sharp image is obtained on the screen for two positions of a thin lens separated by 10 cm. The size of the images in two situations are in the ratio 3 : 3. What is the distance between the screen and the object?
A.	124.5 cm
B.	144.5 cm
C.	65.0 cm
D.	99.0 cm
Answer» E.

Discussion

812.	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

813.	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

814.	In Young's double slit experiment, the slits are 0.5 mm apart and interference pattern is observed on a screen placed at a distance of 1.0 m from the plane containing the slits. If wavelength of the incident light is 6000 Å, then the separation between the third bright fringe and the central maxima is [AMU 1995]
A.	4.0 mm
B.	3.5 mm
C.	3.0 mm
D.	2.5 mm
Answer» C. 3.0 mm

Discussion

815.	A coil is wound as a transformer of rectangular cross-section. If all the linear dimensions of the transformer are increased by a factor 2 and the number of turns per unit length of the coil remain the same, the self inductance increased by a factor of [AIIMS 1980]
A.	16
B.	12
C.	8
D.	4
Answer» D. 4

Discussion

816.	The tension of a stretched string is increased by 69%. In order to keep its frequency of vibration constant, its length must be increased by [KCET 2002]
A.	20%
B.	30%
C.	\[\sqrt{69}%\]
D.	69%
Answer» C. \[\sqrt{69}%\]

Discussion

817.	Length of a string tied to two rigid supports is 40 cm. Maximum length (wavelength in cm) of a stationary wave produced on it is [AIEEE 2002]
A.	20
B.	80
C.	40
D.	120
Answer» C. 40

Discussion

818.	The length of a sonometer wire tuned to a frequency of 250 Hz is 0.60 metre. The frequency of tuning fork with which the vibrating wire will be in tune when the length is made 0.40 metre is [JIPMER 2002]
A.	250 Hz
B.	375 Hz
C.	256 Hz
D.	384 Hz
Answer» C. 256 Hz

Discussion

819.	Assertion : If earth were a hollow sphere, gravitational field intensity at any point inside the earth would be zero. Reason : Net force on a body inside the sphere is zero.
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.
E.	If assertion is false but reason is true.
Answer» B. If both assertion and reason are true but reason is not the correct explanation of the assertion.

Discussion

820.	Ratio of amplitude of interfering waves is 3 : 4. Now ratio of their intensities will be [RPET 2000]
A.	\[\frac{16}{9}\]
B.	49 : 1
C.	\[\frac{9}{16}\]
D.	None of these
Answer» D. None of these

Discussion

821.	Assertion : Orbital velocity of a satellite is greater than its escape velocity. Reason : Orbit of a satellite is within the gravitational field of earth whereas escaping is beyond the gravitational field of earth.
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.
E.	If assertion is false but reason is true.
Answer» F.

Discussion

822.	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

823.	A straight wire of length \[({{\pi }^{2}})\] metre is carrying a current of 2A and the magnetic field due to it is measured at a point distant 1 cm from it. If the wire is to be bent into a circle and is to carry the same current as before, the ratio of the magnetic field at its centre to that obtained in the first case would be [Haryana CEE 1996]
A.	50 : 1
B.	1 : 50
C.	100 : 1
D.	1 : 100
Answer» C. 100 : 1

Discussion

824.	The energy required to knock out the electron in the third orbit of a hydrogen atom is equal to
A.	\[13.6\ eV\]
B.	\[+\frac{13.6}{9}eV\]
C.	\[-\frac{13.6}{3}eV\]
D.	\[-\frac{3}{13.6}eV\]
Answer» C. \[-\frac{13.6}{3}eV\]

Discussion

825.	In the following atoms and moleculates for the transition from n= 2 to n = 1, the spectral line of minimum wavelength will be produced by
A.	Hydrogen atom
B.	Deuterium atom
C.	Uni-ionized helium
D.	di-ionized lithium
Answer» E.

Discussion

826.	What is the ratio of wavelength of radiations emitted when an electron in hydrogen atom jump from fourth orbit to second orbit and from third orbit to second orbit
A.	1.14236111111111
B.	0.852083333333333
C.	0.850694444444445
D.	1.06041666666667
Answer» C. 0.850694444444445

Discussion

827.	Assertion : A positive acceleration of a body can be associated with a ?slowing down? of the body. Reason : Acceleration is a vector quantity.
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.
E.	If assertion is false but reason is true.
Answer» C. If assertion is true but reason is false.

Discussion

828.	If you set up the ninth harmonic on a string fixed at both ends, its frequency compared to the seventh harmonic [AMU (Engg.) 2000]
A.	Higher
B.	Lower
C.	Equal
D.	None of the above
Answer» B. Lower

Discussion

829.	If you set up the seventh harmonic on a string fixed at both ends, how many nodes and antinodes are set up in it [AMU 2000]
A.	8, 7
B.	7, 7
C.	8, 9
D.	9, 8
Answer» B. 7, 7

Discussion

830.	A stretched string of length \[l,\] fixed at both ends can sustain stationary waves of wavelength \[\lambda ,\] given by [UPSEAT 2000; Pb. PET 2004; CPMT 2005]
A.	\[\lambda =\frac{{{n}^{2}}}{2l}\]
B.	\[\lambda =\frac{{{l}^{2}}}{2n}\]
C.	\[\lambda =\frac{2l}{n}\]
D.	\[\lambda =2l\ n\]
Answer» D. \[\lambda =2l\ n\]

Discussion

831.	Assertion : The frequencies of incident, reflected and refracted beam of monochromatic light incident from one medium to another are same Reason : The incident, reflected and refracted rays are coplanar [EAMCET (Engg.) 2000]
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.
E.	If assertion is false but reason is true.
Answer» C. If assertion is true but reason is false.

Discussion

832.	The mass of \[_{7}{{N}^{15}}\] is 15.00011 amu, mass of \[_{8}{{O}^{16}}\] is 15.99492 amu and \[mp=1.00783\text{ }amu\] Determine binding energy of last proton of\[_{8}{{O}^{16}}\].
A.	2.13 MeV
B.	0.13 MeV
C.	10 MeV
D.	12.13 MeV
Answer» E.

Discussion

833.	In a compound microscope, the focal length of objective lens is 1.2 cm and focal length of eye piece is 3.0 cm. When object is kept at 1.25 cm in front of objective, final image is formed at infinity. Magnifying power of the compound microscope should be:
A.	200
B.	100
C.	400
D.	150
Answer» B. 100

Discussion

834.	Two bodies of masses \[{{m}_{1}}\] and \[{{m}_{2}}\] have equal kinetic energies. If \[{{p}_{1}}\] and \[{{p}_{2}}\] are their respective momentum, then ratio \[{{p}_{1}}:{{p}_{2}}\] is equal to [MP PMT 1985; CPMT 1990]
A.	\[{{m}_{1}}:{{m}_{2}}\]
B.	\[{{m}_{2}}:{{m}_{1}}\]
C.	\[\sqrt{{{m}_{1}}}:\sqrt{{{m}_{2}}}\]
D.	\[m_{1}^{2}:m_{2}^{2}\]
Answer» D. \[m_{1}^{2}:m_{2}^{2}\]

Discussion

835.	A person travels along a straight road for the first half time with a velocity \[{{v}_{1}}\] and the next half time with a velocity \[{{v}_{2}}\] . The mean velocity \[V\] of the man is [RPET 1999; BHU 2002]
A.	\[\frac{2}{V}=\frac{1}{{{v}_{1}}}+\frac{1}{{{v}_{2}}}\]
B.	\[V=\frac{{{v}_{1}}+{{v}_{2}}}{2}\]
C.	\[V=\sqrt{{{v}_{1}}{{v}_{2}}}\]
D.	\[V=\sqrt{\frac{{{v}_{1}}}{{{v}_{2}}}}\]
Answer» C. \[V=\sqrt{{{v}_{1}}{{v}_{2}}}\]

Discussion

836.	The activity of a radioactive sample
A.	Can be increased by heating it
B.	Is independent of physical parameter
C.	Cannot be increased by any method
D.	Both [b] and [c]
Answer» E.

Discussion

837.	In the given nuclear reaction A, B, C, D, E represents \[_{92}{{U}^{238}}{{\xrightarrow{\alpha }}_{B}}T{{h}^{A}}{{\xrightarrow{\beta }}_{D}}P{{a}^{C}}{{\xrightarrow{E}}_{92}}{{U}^{234}}\]
A.	A = 234, B = 90, C = 234, D = 91, E = \[\beta \]
B.	A = 234, B = 90, C = 238, D = 94, E = \[\alpha \]
C.	A = 238, B = 93, C = 234, D = 91, E = \[\beta \]
D.	A = 234, B = 90, C = 234, D = 93, E = \[\alpha \]
Answer» B. A = 234, B = 90, C = 238, D = 94, E = \[\alpha \]

Discussion

838.	If the total binding energies of \[_{1}^{2}H\], \[_{2}^{4}He\], \[_{26}^{56}Fe\] & \[_{92}^{235}U\] nuclei are 2.22, 28.3, 492 and 1786 MeV respectively, identify the most stable nucleus of the following
A.	\[_{26}^{56}Fe\]
B.	\[_{1}^{2}H\]
C.	\[_{92}^{235}U\]
D.	\[_{2}^{4}He\]
Answer» B. \[_{1}^{2}H\]

Discussion

839.	The minimum wavelength of the X-rays produced by electrons accelerated through a potential difference of V volts is directly proportional to [CBSE PMT 1996]
A.	\[\sqrt{V}\]
B.	\[{{V}^{2}}\]
C.	\[1/\sqrt{V}\]
D.	\[1/V\]
Answer» E.

Discussion

840.	An X-ray machine has an accelerating potential difference of 25,000 volts. By calculation the shortest wavelength will be obtained as (\[h=6.62\times {{10}^{-34}}\] J?sec; e = \[1.6\times {{10}^{-19}}\]coulomb) [MP PET 1994]
A.	0.25 Å
B.	0.50 Å
C.	1.00 Å
D.	2.50 Å
Answer» C. 1.00 Å

Discussion

841.	Surface tension of a liquid is found to be influenced by [ISM Dhanbad 1994]
A.	It increases with the increase of temperature
B.	Nature of the liquid in contact
C.	Presence of soap that increases it
D.	Its variation with the concentration of the liquid
Answer» E.

Discussion

842.	A varying current in a coil changes from 10 amp to zero in 0.5 sec. If average EMF is induced in the coil is 220 volts, the self-inductance of coil is [EAMCET 1994; MH CET (Med.) 1999]
A.	5 H
B.	10 H
C.	11 H
D.	12 H
Answer» D. 12 H

Discussion

843.	Assertion : The velocity of flow of a liquid is smaller when pressure is larger and viceversa. Reason : According to Bernoulli's theorem, for the stream line flow of an ideal liquid, the total energy per unit mass remains constant.
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.
E.	If assertion is false but reason is true.
Answer» B. If both assertion and reason are true but reason is not the correct explanation of the assertion.

Discussion

844.	Coating of strontium oxide on Tungsten cathode in a valve is good for thermionic emission because [RPMT 1998]
A.	Work function decreases
B.	Work function increases
C.	Conductivity of cathode increases
D.	Cathode can be heated to high temperature
Answer» B. Work function increases

Discussion

845.	Which of the following statements is correct [MP PET 1992]
A.	Hooke's law is applicable only within elastic limit
B.	The adiabatic and isothermal elastic constants of a gas are equal
C.	Young's modulus is dimensionless
D.	Stress multiplied by strain is equal to the stored energy
Answer» B. The adiabatic and isothermal elastic constants of a gas are equal

Discussion

846.	A cut diamond sparkles because of its [NCERT 1974; RPET 1996; AFMC 2005]
A.	Hardness
B.	High refractive index
C.	Emission of light by the diamond
D.	Absorption of light by the diamond
Answer» C. Emission of light by the diamond

Discussion

847.	Finger prints on a piece of paper may be detected by sprinkling fluorescent powder on the paper and then looking it into [MP PET/PMT 1988]
A.	Mercury light
B.	Sunlight
C.	Infrared light
D.	Ultraviolet light
Answer» E.

Discussion

848.	A diver in a swimming pool wants to signal his distress to a person lying on the edge of the pool by flashing his water proof flash light [NCERT 1972]
A.	He must direct the beam vertically upwards
B.	He has to direct the beam horizontally
C.	He has to direct the beam at an angle to the vertical which is slightly less than the critical angle of incidence for total internal reflection
D.	He has to direct the beam at an angle to the vertical which is slightly more than the critical angle of incidence for the total internal reflection
Answer» D. He has to direct the beam at an angle to the vertical which is slightly more than the critical angle of incidence for the total internal reflection

Discussion

849.	The temperature-entropy diagram of a reversible engine cycle is given in the figure. Its efficiency is
A.	\[\frac{1}{4}\]
B.	\[\frac{1}{2}\]
C.	\[\frac{2}{3}\]
D.	\[\frac{1}{3}\]
Answer» E.

Discussion

850.	If \[\vec{a}\times \vec{b}\,+\vec{c}=0,\] then \[\vec{a}\times \vec{b}\,\] is
A.	\[\vec{a}\times \vec{b}\]
B.	\[\vec{c}\times \vec{b}\,\]
C.	\[\vec{a}\times \vec{c}\]
D.	None of these
Answer» B. \[\vec{c}\times \vec{b}\,\]

Discussion

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

Image formed by a convex mirror is [MP PET 1993]

A convex mirror is used to form the image of an object. Then which of the following statements is wrong [CPMT 1973]

In a concave mirror experiment, an object is placed at a distance \[{{x}_{1}}\] from the focus and the image is formed at a distance \[{{x}_{2}}\] from the focus. The focal length of the mirror would be [MP PET 1997]

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]

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]

In double slit experiment, the angular width of the fringes is 0.20o for the sodium light (l =\[5890\,{AA}\]). In order to increase the angular width of the fringes by 10%, the necessary change in the wavelength is [MP PMT 1997]

Interference was observed in interference chamber when air was present, now the chamber is evacuated and if the same light is used, a careful observer will see [CBSE PMT 1993; DPMT 2000; BHU 2002]

The addition of antimony atoms to a sample of intrinsic germanium transforms it to a material which is [AMU 1995]

Assertion : In javelin throw, the athlete throws the projectile at an angle slightly more than 45°. Reason : The maximum range does not depends upon angle of projection.

An object is located in a fixed position in front of a screen. Sharp image is obtained on the screen for two positions of a thin lens separated by 10 cm. The size of the images in two situations are in the ratio 3 : 3. What is the distance between the screen and the object?

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]

A coil is wound as a transformer of rectangular cross-section. If all the linear dimensions of the transformer are increased by a factor 2 and the number of turns per unit length of the coil remain the same, the self inductance increased by a factor of [AIIMS 1980]

The tension of a stretched string is increased by 69%. In order to keep its frequency of vibration constant, its length must be increased by [KCET 2002]

Length of a string tied to two rigid supports is 40 cm. Maximum length (wavelength in cm) of a stationary wave produced on it is [AIEEE 2002]

The length of a sonometer wire tuned to a frequency of 250 Hz is 0.60 metre. The frequency of tuning fork with which the vibrating wire will be in tune when the length is made 0.40 metre is [JIPMER 2002]

Assertion : If earth were a hollow sphere, gravitational field intensity at any point inside the earth would be zero. Reason : Net force on a body inside the sphere is zero.

Ratio of amplitude of interfering waves is 3 : 4. Now ratio of their intensities will be [RPET 2000]

Assertion : Orbital velocity of a satellite is greater than its escape velocity. Reason : Orbit of a satellite is within the gravitational field of earth whereas escaping is beyond the gravitational field of earth.

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

The energy required to knock out the electron in the third orbit of a hydrogen atom is equal to

In the following atoms and moleculates for the transition from n= 2 to n = 1, the spectral line of minimum wavelength will be produced by

What is the ratio of wavelength of radiations emitted when an electron in hydrogen atom jump from fourth orbit to second orbit and from third orbit to second orbit

Assertion : A positive acceleration of a body can be associated with a ?slowing down? of the body. Reason : Acceleration is a vector quantity.

If you set up the ninth harmonic on a string fixed at both ends, its frequency compared to the seventh harmonic [AMU (Engg.) 2000]

If you set up the seventh harmonic on a string fixed at both ends, how many nodes and antinodes are set up in it [AMU 2000]

A stretched string of length \[l,\] fixed at both ends can sustain stationary waves of wavelength \[\lambda ,\] given by [UPSEAT 2000; Pb. PET 2004; CPMT 2005]

Assertion : The frequencies of incident, reflected and refracted beam of monochromatic light incident from one medium to another are same Reason : The incident, reflected and refracted rays are coplanar [EAMCET (Engg.) 2000]

The mass of \[_{7}{{N}^{15}}\] is 15.00011 amu, mass of \[_{8}{{O}^{16}}\] is 15.99492 amu and \[mp=1.00783\text{ }amu\] Determine binding energy of last proton of\[_{8}{{O}^{16}}\].

In a compound microscope, the focal length of objective lens is 1.2 cm and focal length of eye piece is 3.0 cm. When object is kept at 1.25 cm in front of objective, final image is formed at infinity. Magnifying power of the compound microscope should be:

Two bodies of masses \[{{m}_{1}}\] and \[{{m}_{2}}\] have equal kinetic energies. If \[{{p}_{1}}\] and \[{{p}_{2}}\] are their respective momentum, then ratio \[{{p}_{1}}:{{p}_{2}}\] is equal to [MP PMT 1985; CPMT 1990]

A person travels along a straight road for the first half time with a velocity \[{{v}_{1}}\] and the next half time with a velocity \[{{v}_{2}}\] . The mean velocity \[V\] of the man is [RPET 1999; BHU 2002]

The activity of a radioactive sample

In the given nuclear reaction A, B, C, D, E represents \[_{92}{{U}^{238}}{{\xrightarrow{\alpha }}_{B}}T{{h}^{A}}{{\xrightarrow{\beta }}_{D}}P{{a}^{C}}{{\xrightarrow{E}}_{92}}{{U}^{234}}\]

If the total binding energies of \[_{1}^{2}H\], \[_{2}^{4}He\], \[_{26}^{56}Fe\] & \[_{92}^{235}U\] nuclei are 2.22, 28.3, 492 and 1786 MeV respectively, identify the most stable nucleus of the following

The minimum wavelength of the X-rays produced by electrons accelerated through a potential difference of V volts is directly proportional to [CBSE PMT 1996]

An X-ray machine has an accelerating potential difference of 25,000 volts. By calculation the shortest wavelength will be obtained as (\[h=6.62\times {{10}^{-34}}\] J?sec; e = \[1.6\times {{10}^{-19}}\]coulomb) [MP PET 1994]

Surface tension of a liquid is found to be influenced by [ISM Dhanbad 1994]

A varying current in a coil changes from 10 amp to zero in 0.5 sec. If average EMF is induced in the coil is 220 volts, the self-inductance of coil is [EAMCET 1994; MH CET (Med.) 1999]

Assertion : The velocity of flow of a liquid is smaller when pressure is larger and viceversa. Reason : According to Bernoulli's theorem, for the stream line flow of an ideal liquid, the total energy per unit mass remains constant.

Coating of strontium oxide on Tungsten cathode in a valve is good for thermionic emission because [RPMT 1998]

Which of the following statements is correct [MP PET 1992]

A cut diamond sparkles because of its [NCERT 1974; RPET 1996; AFMC 2005]

Finger prints on a piece of paper may be detected by sprinkling fluorescent powder on the paper and then looking it into [MP PET/PMT 1988]

A diver in a swimming pool wants to signal his distress to a person lying on the edge of the pool by flashing his water proof flash light [NCERT 1972]

The temperature-entropy diagram of a reversible engine cycle is given in the figure. Its efficiency is

If \[\vec{a}\times \vec{b}\,+\vec{c}=0,\] then \[\vec{a}\times \vec{b}\,\] is