12583 + Mcqs in Physics Page 12 McqOptions

551.	Consider the two following statements A and B and identify the correct choice given in the answers; [A] In photovlotaic cells the photoelectric current produced is not proportional to the, intensity of incident light. [B] In gas filled photoemissive cells, the velocity of photoelectrons depends on the wavelength of the incident radiation.
A.	Both A and B are true
B.	Both A and B are false
C.	A is true but B is false
D.	A is false B is true
Answer» E.

Discussion

552.	Which of the following has negative temperature coefficient of resistance [AFMC 2004]
A.	Copper
B.	Aluminium
C.	Iron
D.	Germanium
Answer» E.

Discussion

553.	A closely wound coil of 100 turns and area of cross-section \[1\ c{{m}^{2}}\] has a coefficient of self-induction 1 mH. The magnetic induction in the centre of the core of the coil when a current of 2A flows in it, will be [MP PET 1992]
A.	\[0.022\ Wb{{m}^{-2}}\]
B.	\[0.4\ Wb\ {{m}^{-2}}\]
C.	\[0.8\ Wb\ {{m}^{-2}}\]
D.	\[1\ Wb\ {{m}^{-2}}\]
Answer» B. \[0.4\ Wb\ {{m}^{-2}}\]

Discussion

554.	The energy required to charge a capacitor of \[5\,\mu \,F\] by connecting a d.c. source of 20 kV is [Pb. PMT 2002]
A.	10 kJ
B.	5 kJ
C.	2 kJ
D.	1 kJ
Answer» E.

Discussion

555.	Acceleration due to gravity 'g' for a body of mass 'm' on earth's surface is proportional to (Radius of earth=R, mass of earth=M) [DCE 2004]
A.	\[GM/{{R}^{2}}\]
B.	\[{{m}^{0}}\]
C.	\[mM\]
D.	\[1/{{R}^{3/2}}\]
Answer» B. \[{{m}^{0}}\]

Discussion

556.	In a Millikan's oil drop experiment the charge on an oil drop is calculated to be \[6.35\times {{10}^{-19}}C\]. The number of excess electrons on the drop is [MNR 1998]
A.	3.9
B.	4
C.	4.2
D.	6
Answer» C. 4.2

Discussion

557.	Assertion : A negative acceleration of a body is associated with a slowing down of a body. Reason : Acceleration is 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

558.	The resistance and inductance of series circuit are \[5\Omega \] and 20H respectively. At the instant of closing the switch, the current is increasing at the rate 4A-s. The supply voltage is [MP PMT 2004]
A.	20 V
B.	80 V
C.	120 V
D.	100 V
Answer» C. 120 V

Discussion

559.	Assertion : Beats can also be observed by two light sources as in sound. Reason : Light sources have constant phase deference.
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

560.	Assertion : It is not possible to have interference between the waves produced by two violins. Reason : For interference of two waves the phase difference between the waves must remain 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

561.	Assertion : Sound produced by an open organ pipe is richer than the sound produced by a closed organ pipe. Reason : Outside air can enter the pipe from both ends, in case of open organ pipe.
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

562.	The angular velocities of three bodies in simple harmonic motion are \[{{\omega }_{1}},\,{{\omega }_{2}},\,{{\omega }_{3}}\] with their respective amplitudes as \[{{A}_{1}},\,{{A}_{2}},\,{{A}_{3}}\]. If all the three bodies have same mass and velocity, then [BHU 2002]
A.	\[{{A}_{1}}{{\omega }_{1}}={{A}_{2}}{{\omega }_{2}}={{A}_{3}}{{\omega }_{3}}\]
B.	\[{{A}_{1}}{{\omega }_{1}}^{2}={{A}_{2}}{{\omega }_{2}}^{2}={{A}_{3}}{{\omega }_{3}}^{2}\]
C.	\[{{A}_{1}}^{2}{{\omega }_{1}}={{A}_{2}}^{2}{{\omega }_{2}}={{A}_{3}}^{2}{{\omega }_{3}}\]
D.	\[{{A}_{1}}^{2}{{\omega }_{1}}^{2}={{A}_{2}}^{2}{{\omega }_{2}}^{2}={{A}^{2}}\]
Answer» B. \[{{A}_{1}}{{\omega }_{1}}^{2}={{A}_{2}}{{\omega }_{2}}^{2}={{A}_{3}}{{\omega }_{3}}^{2}\]

Discussion

563.	One car moving on a straight road covers one third of the distance with 20 km/hr and the rest with 60 km/hr. The average speed is [MP PMT 1999; CPMT 2002]
A.	40 km/hr
B.	80 km/hr
C.	\[46\frac{2}{3}\] km/hr
D.	36 km/hr
Answer» E.

Discussion

564.	Two waves are represented by the equations \[{{y}_{1}}=a\sin (\omega t+kx+0.57)m\] and \[{{y}_{2}}=a\cos \]\[(\omega t+kx)m\], where x is in meter and t in sec. The phase difference between them is
A.	1.0 radian
B.	1.25 radian
C.	1.57 radian
D.	0.57 radian
Answer» B. 1.25 radian

Discussion

565.	Atomic weight of boron is 10.81 and it has two isotopes \[_{5}{{B}^{10}}\] and\[_{5}{{B}^{11}}\]. Then ratio of \[_{5}{{B}^{10}}{{:}_{5}}{{B}^{11}}\] in nature would be
A.	19 : 81
B.	10 : 11
C.	15 : 16
D.	81 : 19
Answer» B. 10 : 11

Discussion

566.	Assuming that the mass m of the largest stone that can be moved by a flowing river depends upon the velocity v of the water, its density \[\rho \] and the acceleration due to gravity g. Then m is directly proportional to:
A.	\[{{\nu }^{3}}\]
B.	\[{{\nu }^{4}}\]
C.	\[{{\nu }^{5}}\]
D.	\[{{\nu }^{6}}\]
Answer» E.

Discussion

567.	19 g of water at \[30{}^\circ C\] and 5 g of ice at \[-\,20{}^\circ C\]are mixed together in a calorimeter. What is the final temperature of the mixture? Given specific heat of ice \[=0.5 cal {{g}^{-1}} {{\left( {}^\circ C \right)}^{-1}}\]and latent heat of fusion of ice\[=80cal\,\,{{g}^{-1}}\]
A.	\[0{}^\circ C\]
B.	\[-5{}^\circ C\]
C.	\[5{}^\circ C\]
D.	\[10{}^\circ C\]
Answer» D. \[10{}^\circ C\]

Discussion

568.	When the number of turns and the length of the solenoid are doubled keeping the area of cross-section same, the inductance [CBSE PMT 1993; MH CET 2000]
A.	Remains the same
B.	Is halved
C.	Is doubled
D.	Becomes four times
Answer» D. Becomes four times

Discussion

569.	In a Young?s double slit experiment, the source illuminating the slits is changed from blue to violet. The width of the fringes [KCET 2002]
A.	Increases
B.	Decreases
C.	Becomes unequal
D.	Remains constant
Answer» C. Becomes unequal

Discussion

570.	In Young?s double slit experiment, the wavelength of the light used is doubled and distance between two slits is half of initial distance, the resultant fringe width becomes [AIEEE 2002]
A.	2 times
B.	3 times
C.	4 times
D.	1/2 times
Answer» D. 1/2 times

Discussion

571.	In Young?s double slit experiment, the central bright fringe can be identified [KCET 2002]
A.	By using white light instead of monochromatic light
B.	As it is narrower than other bright fringes
C.	As it is wider than other bright fringes
D.	As it has a greater intensity than the other bright fringes
Answer» B. As it is narrower than other bright fringes

Discussion

572.	If work done in increasing the size of a soap film from \[10\ cm\times 6\ cm\] to \[10\ cm\times 11\ cm\] is \[2\times {{10}^{-4}}J,\] then the surface tension is [AIIMS 2000]
A.	\[2\times {{10}^{-2}}N{{m}^{-1}}\]
B.	\[2\times {{10}^{-4}}N{{m}^{-1}}\]
C.	\[2\times {{10}^{-6}}N{{m}^{-1}}\]
D.	\[2\times {{10}^{-8}}N{{m}^{-1}}\]
Answer» B. \[2\times {{10}^{-4}}N{{m}^{-1}}\]

Discussion

573.	Two particles, each of mass 2 kg are put at (2m, 0) and (0, 2m), as shown in figure. Now 1 kg mass of particle A is put on to the particle B. The change in x-coordinate of centre of mass of the system is
A.	0.5m
B.	1m
C.	1.5m
D.	None of these
Answer» B. 1m

Discussion

574.	A simple pendulum is taken from the equator to the pole. Its period [Kerala (PET/PMT) 2005]
A.	Decreases
B.	Increases
C.	Remains the same
D.	Decreases and then increases
Answer» B. Increases

Discussion

575.	A pendulum of length 2m lift at P. When it reaches Q, it losses 10% of its total energy due to air resistance. The velocity at Q is [DCE 1998]
A.	6 m/sec
B.	1 m/sec
C.	2 m/sec
D.	8 m/sec
Answer» B. 1 m/sec

Discussion

576.	A pulley fixed to the ceiling carries a string with blocks of mass m and 3 m attached to its ends. The masses of string and pulley are negligible. When the system is released, its centre of mass moves with what acceleration?
A.	0
B.	\[-g/4\]
C.	\[g/2\]
D.	\[-g/2\]
Answer» D. \[-g/2\]

Discussion

577.	Starting with the same initial conditions, an ideal gas expands from volume \[{{V}_{1}}\] to \[{{V}_{2}}\] in three different ways. The work done by the gas is \[{{W}_{1}}\] if the process is purely isothermal, \[{{W}_{2}}\] if purely isobaric and \[{{W}_{3}}\] if purely adiabatic. Then
A.	\[{{W}_{2}}>{{W}_{1}}>{{W}_{3}}\]
B.	\[{{W}_{2}}>{{W}_{3}}>{{W}_{1}}\]
C.	\[{{W}_{1}}>{{W}_{2}}>{{W}_{3}}\]
D.	\[{{W}_{1}}>{{W}_{3}}>{{W}_{2}}\]
Answer» B. \[{{W}_{2}}>{{W}_{3}}>{{W}_{1}}\]

Discussion

578.	Assertion : A capacitor of suitable capacitance can be used in an ac circuit in place of the choke coil. Reason : A capacitor blocks dc and allows ac only.
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

579.	The current in a coil of inductance 5 H decreases at the rate of 2 A/s. The induced e.m.f. is [MH CET 2002]
A.	2 V
B.	5 V
C.	10 V
D.	- 10 V
Answer» D. - 10 V

Discussion

580.	A mixture consists of two radioactive materials \[{{A}_{1}}\] and \[{{A}_{2}}\] with half-lives of 20 s and 10 s respectively. Initially the mixture has 40 g of \[{{A}_{1}}\] and 160 g of \[{{A}_{2}}\]. The amount of the two in the mixture will become equal after
A.	60s
B.	80s
C.	20s
D.	40s
Answer» E.

Discussion

581.	Which of the following phenomena can explain quantum nature of light [RPMT 2001]
A.	Photoelectric effect
B.	Interference
C.	Diffraction
D.	Polarisation
Answer» B. Interference

Discussion

582.	The phase difference between incident wave and reflected wave is 180° when light ray [RPMT 1998, 2001]
A.	Enters into glass from air
B.	Enters into air from glass
C.	Enters into glass from diamond
D.	Enters into water from glass
Answer» B. Enters into air from glass

Discussion

583.	Which of the following is not a property of light [AFMC 2005]
A.	It requires a material medium for propagation
B.	It can travel through vacuum
C.	It involves transportation of energy
D.	It has finite speed
Answer» B. It can travel through vacuum

Discussion

584.	Three charges \[4q,\,Q\] and \[q\] are in a straight line in the position of 0, \[l/2\] and \[l\] respectively. The resultant force on \[q\] will be zero, if \[Q=\] [CPMT 1980]
A.	? q
B.	\[-\,2q\]
C.	\[-\frac{q}{2}\]
D.	\[4q\]
Answer» B. \[-\,2q\]

Discussion

585.	A force \[(\vec{F})=3\hat{i}+c\hat{j}+2\hat{k}\] acting on a particle causes a displacement: \[(\vec{s})\,=-4\hat{i}+2\hat{j}+3\hat{k}\] in its own direction. If the work done is \[6\,J,\] then the value of \['c'\]is [CBSE PMT 2002]
A.	0
B.	1
C.	6
D.	12
Answer» D. 12

Discussion

586.	Minimum number of prisms required to make a combination which is ?Achromatic? as well as ?Direct Vision? is:
A.	2
B.	3
C.	4
D.	11
Answer» B. 3

Discussion

587.	A current of 10A is passing through a long wire which has semicircular loop of the radius 20cm as shown in the figure. Magnetic field produced at the centre of the loop is [Orissa JEE 2003]
A.	\[10\,\pi \mu T\]
B.	\[5\,\pi \mu T\]
C.	\[4\,\pi \mu T\]
D.	\[2\,\pi \mu T\]
Answer» C. \[4\,\pi \mu T\]

Discussion

588.	Two coherent sources have intensity in the ratio of \[\frac{100}{1}\]. Ratio of (intensity) max/(intensity) min is [RPET 2000]
A.	\[\frac{1}{100}\]
B.	\[\frac{1}{10}\]
C.	\[\frac{10}{1}\]
D.	\[\frac{3}{2}\]
Answer» E.

Discussion

589.	The two waves represented by y1 = a sin(wt) and \[{{y}_{2}}=b\cos (\omega t)\] have a phase difference of [MP PMT 2000]
A.	0
B.	\[\frac{\pi }{2}\]
C.	p
D.	\[\frac{\pi }{4}\]
Answer» C. p

Discussion

590.	If two waves represented by \[{{y}_{1}}=4\sin \omega t\] and \[{{y}_{2}}=3\sin \left( \omega t+\frac{\pi }{3} \right)\] interfere at a point, the amplitude of the resulting wave will be about [MP PMT 2000]
A.	7
B.	6
C.	5
D.	3.5
Answer» C. 5

Discussion

591.	In a Young's experiment, two coherent sources are placed 0.90 mm apart and the fringes are observed one metre away. If it produces the second dark fringe at a distance of 1 mm from the central fringe, the wavelength of monochromatic light used would be [CBSE PMT 1992; KCET 2004]
A.	\[60\times {{10}^{-4}}cm\]
B.	\[10\times {{10}^{-4}}cm\]
C.	\[10\times {{10}^{-5}}cm\]
D.	\[6\times {{10}^{-5}}cm\]
Answer» E.

Discussion

592.	A LC circuit is in the state of resonance. If \[C=0.1\mu F\] and \[L=0.25\]henry. Neglecting ohmic resistance of circuit what is the frequency of oscillations [BHU 2003; MP PMT 2005]
A.	1007 Hz
B.	100 Hz
C.	109 Hz
D.	500 Hz
Answer» B. 100 Hz

Discussion

593.	In Young's double slit experiment, carried out with light of wavelength l = 5000 Å, the distance between the slits is 0.2 mm and the screen is at 200 cm from the slits. The central maximum is at x =0. The third maximum (taking the central maximum as zeroth maximum) will be at x equal to [CBSE PMT 1992; MH CET 2002]
A.	1.67 cm
B.	1.5 cm
C.	0.5 cm
D.	5.0 cm
Answer» C. 0.5 cm

Discussion

594.	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

595.	A mango tree is at the bank of river and one of the branch of tree extends over the river. A tortoise lives in river. A mango falls just above the tortoise. The acceleration of the mango falling from tree appearing to the tortoise is (Refractive index of water is 4/3 and the tortoise is stationary)
A.	g
B.	3g/4
C.	4g/3
D.	None of these
Answer» D. None of these

Discussion

596.	Assertion : A beaker is completely filled with water at 4°C. It will overflow, both when heated or cooled. Reason : There is expansion of water below and above 4°C.
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

597.	Equal charges \[q\] are placed at the four corners \[A,\,B,\,C,\,D\] of a square of length \[a\]. The magnitude of the force on the charge at B will be [MP PMT 1994; DPMT 2001]
A.	\[\frac{3{{q}^{2}}}{4\pi {{\varepsilon }_{0}}{{a}^{2}}}\]
B.	\[\frac{4{{q}^{2}}}{4\pi {{\varepsilon }_{0}}{{a}^{2}}}\]
C.	\[\left( \frac{1+2\sqrt{2}}{2} \right)\frac{{{q}^{2}}}{4\pi {{\varepsilon }_{0}}{{a}^{2}}}\]
D.	\[\left( 2+\frac{1}{\sqrt{2}} \right)\frac{{{q}^{2}}}{4\pi {{\varepsilon }_{0}}{{a}^{2}}}\]
Answer» E.

Discussion

598.	A uniform metal chain is placed on a rough table such that one end of chain hangs down over the edge of the table. When one-third of its length hangs over the edge, the chain starts sliding. Then, the coefficient of static friction is [Kerala PET 2005]
A.	\[\frac{3}{4}\]
B.	\[\frac{1}{4}\]
C.	\[\frac{2}{3}\]
D.	\[\frac{1}{2}\]
Answer» E.

Discussion

599.	A ball of mass m moving with a constant velocity strikes against a ball of same mass at rest. If e= coefficient of restitution, then what will be the ratio of velocity of two balls after collision?
A.	\[\frac{1-e}{1+e}\]
B.	\[\frac{e-1}{e+1}\]
C.	\[\frac{1+e}{1-e}\]
D.	\[\frac{2+e}{e-1}\]
Answer» B. \[\frac{e-1}{e+1}\]

Discussion

600.	Which of the following is not the unit of time [CPMT 1991; NCERT 1990; DPMT 1987; AFMC 1996]
A.	Micro second
B.	Leap year
C.	Lunar months
D.	Parallactic second
E.	(e) Solar day
Answer» E. (e) Solar day

Discussion

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

Which of the following has negative temperature coefficient of resistance [AFMC 2004]

A closely wound coil of 100 turns and area of cross-section \[1\ c{{m}^{2}}\] has a coefficient of self-induction 1 mH. The magnetic induction in the centre of the core of the coil when a current of 2A flows in it, will be [MP PET 1992]

The energy required to charge a capacitor of \[5\,\mu \,F\] by connecting a d.c. source of 20 kV is [Pb. PMT 2002]

Acceleration due to gravity 'g' for a body of mass 'm' on earth's surface is proportional to (Radius of earth=R, mass of earth=M) [DCE 2004]

In a Millikan's oil drop experiment the charge on an oil drop is calculated to be \[6.35\times {{10}^{-19}}C\]. The number of excess electrons on the drop is [MNR 1998]

Assertion : A negative acceleration of a body is associated with a slowing down of a body. Reason : Acceleration is vector quantity.

The resistance and inductance of series circuit are \[5\Omega \] and 20H respectively. At the instant of closing the switch, the current is increasing at the rate 4A-s. The supply voltage is [MP PMT 2004]

Assertion : Beats can also be observed by two light sources as in sound. Reason : Light sources have constant phase deference.

Assertion : It is not possible to have interference between the waves produced by two violins. Reason : For interference of two waves the phase difference between the waves must remain constant.

Assertion : Sound produced by an open organ pipe is richer than the sound produced by a closed organ pipe. Reason : Outside air can enter the pipe from both ends, in case of open organ pipe.

The angular velocities of three bodies in simple harmonic motion are \[{{\omega }_{1}},\,{{\omega }_{2}},\,{{\omega }_{3}}\] with their respective amplitudes as \[{{A}_{1}},\,{{A}_{2}},\,{{A}_{3}}\]. If all the three bodies have same mass and velocity, then [BHU 2002]

One car moving on a straight road covers one third of the distance with 20 km/hr and the rest with 60 km/hr. The average speed is [MP PMT 1999; CPMT 2002]

Two waves are represented by the equations \[{{y}_{1}}=a\sin (\omega t+kx+0.57)m\] and \[{{y}_{2}}=a\cos \]\[(\omega t+kx)m\], where x is in meter and t in sec. The phase difference between them is

Atomic weight of boron is 10.81 and it has two isotopes \[_{5}{{B}^{10}}\] and\[_{5}{{B}^{11}}\]. Then ratio of \[_{5}{{B}^{10}}{{:}_{5}}{{B}^{11}}\] in nature would be

Assuming that the mass m of the largest stone that can be moved by a flowing river depends upon the velocity v of the water, its density \[\rho \] and the acceleration due to gravity g. Then m is directly proportional to:

19 g of water at \[30{}^\circ C\] and 5 g of ice at \[-\,20{}^\circ C\]are mixed together in a calorimeter. What is the final temperature of the mixture? Given specific heat of ice \[=0.5 cal {{g}^{-1}} {{\left( {}^\circ C \right)}^{-1}}\]and latent heat of fusion of ice\[=80cal\,\,{{g}^{-1}}\]

When the number of turns and the length of the solenoid are doubled keeping the area of cross-section same, the inductance [CBSE PMT 1993; MH CET 2000]

In a Young?s double slit experiment, the source illuminating the slits is changed from blue to violet. The width of the fringes [KCET 2002]

In Young?s double slit experiment, the wavelength of the light used is doubled and distance between two slits is half of initial distance, the resultant fringe width becomes [AIEEE 2002]

In Young?s double slit experiment, the central bright fringe can be identified [KCET 2002]

If work done in increasing the size of a soap film from \[10\ cm\times 6\ cm\] to \[10\ cm\times 11\ cm\] is \[2\times {{10}^{-4}}J,\] then the surface tension is [AIIMS 2000]

Two particles, each of mass 2 kg are put at (2m, 0) and (0, 2m), as shown in figure. Now 1 kg mass of particle A is put on to the particle B. The change in x-coordinate of centre of mass of the system is

A simple pendulum is taken from the equator to the pole. Its period [Kerala (PET/PMT) 2005]

A pendulum of length 2m lift at P. When it reaches Q, it losses 10% of its total energy due to air resistance. The velocity at Q is [DCE 1998]

A pulley fixed to the ceiling carries a string with blocks of mass m and 3 m attached to its ends. The masses of string and pulley are negligible. When the system is released, its centre of mass moves with what acceleration?

Starting with the same initial conditions, an ideal gas expands from volume \[{{V}_{1}}\] to \[{{V}_{2}}\] in three different ways. The work done by the gas is \[{{W}_{1}}\] if the process is purely isothermal, \[{{W}_{2}}\] if purely isobaric and \[{{W}_{3}}\] if purely adiabatic. Then

Assertion : A capacitor of suitable capacitance can be used in an ac circuit in place of the choke coil. Reason : A capacitor blocks dc and allows ac only.

The current in a coil of inductance 5 H decreases at the rate of 2 A/s. The induced e.m.f. is [MH CET 2002]

A mixture consists of two radioactive materials \[{{A}_{1}}\] and \[{{A}_{2}}\] with half-lives of 20 s and 10 s respectively. Initially the mixture has 40 g of \[{{A}_{1}}\] and 160 g of \[{{A}_{2}}\]. The amount of the two in the mixture will become equal after

Which of the following phenomena can explain quantum nature of light [RPMT 2001]

The phase difference between incident wave and reflected wave is 180° when light ray [RPMT 1998, 2001]

Which of the following is not a property of light [AFMC 2005]

Three charges \[4q,\,Q\] and \[q\] are in a straight line in the position of 0, \[l/2\] and \[l\] respectively. The resultant force on \[q\] will be zero, if \[Q=\] [CPMT 1980]

A force \[(\vec{F})=3\hat{i}+c\hat{j}+2\hat{k}\] acting on a particle causes a displacement: \[(\vec{s})\,=-4\hat{i}+2\hat{j}+3\hat{k}\] in its own direction. If the work done is \[6\,J,\] then the value of \['c'\]is [CBSE PMT 2002]

Minimum number of prisms required to make a combination which is ?Achromatic? as well as ?Direct Vision? is:

A current of 10A is passing through a long wire which has semicircular loop of the radius 20cm as shown in the figure. Magnetic field produced at the centre of the loop is [Orissa JEE 2003]

Two coherent sources have intensity in the ratio of \[\frac{100}{1}\]. Ratio of (intensity) max/(intensity) min is [RPET 2000]

The two waves represented by y1 = a sin(wt) and \[{{y}_{2}}=b\cos (\omega t)\] have a phase difference of [MP PMT 2000]

If two waves represented by \[{{y}_{1}}=4\sin \omega t\] and \[{{y}_{2}}=3\sin \left( \omega t+\frac{\pi }{3} \right)\] interfere at a point, the amplitude of the resulting wave will be about [MP PMT 2000]

In a Young's experiment, two coherent sources are placed 0.90 mm apart and the fringes are observed one metre away. If it produces the second dark fringe at a distance of 1 mm from the central fringe, the wavelength of monochromatic light used would be [CBSE PMT 1992; KCET 2004]

A LC circuit is in the state of resonance. If \[C=0.1\mu F\] and \[L=0.25\]henry. Neglecting ohmic resistance of circuit what is the frequency of oscillations [BHU 2003; MP PMT 2005]

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 mango tree is at the bank of river and one of the branch of tree extends over the river. A tortoise lives in river. A mango falls just above the tortoise. The acceleration of the mango falling from tree appearing to the tortoise is (Refractive index of water is 4/3 and the tortoise is stationary)

Assertion : A beaker is completely filled with water at 4°C. It will overflow, both when heated or cooled. Reason : There is expansion of water below and above 4°C.

Equal charges \[q\] are placed at the four corners \[A,\,B,\,C,\,D\] of a square of length \[a\]. The magnitude of the force on the charge at B will be [MP PMT 1994; DPMT 2001]

A uniform metal chain is placed on a rough table such that one end of chain hangs down over the edge of the table. When one-third of its length hangs over the edge, the chain starts sliding. Then, the coefficient of static friction is [Kerala PET 2005]

A ball of mass m moving with a constant velocity strikes against a ball of same mass at rest. If e= coefficient of restitution, then what will be the ratio of velocity of two balls after collision?

Which of the following is not the unit of time [CPMT 1991; NCERT 1990; DPMT 1987; AFMC 1996]