12583 + Mcqs in Physics Page 194 McqOptions

9651.	If a slab of insulating material \[4\times {{10}^{-3}}m\] thick is introduced between the plates of a parallel plate capacitor, the separation between plates has to be increased by \[3.5\times {{10}^{-3}}\,m\] to restore the capacity to original value. The dielectric constant of the material will be [AMU (Med.) 1999]
A.	6
B.	8
C.	10
D.	12
Answer» C. 10

Discussion

9652.	If the kinetic energy of a body becomes four times of its initial value, then new momentum will [AIIMS 1998; AIIMS 2002; KCET 2000; J & K CET 2004]
A.	Becomes twice its initial value
B.	Become three times its initial value
C.	Become four times its initial value
D.	Remains constant
Answer» B. Become three times its initial value

Discussion

9653.	The kinetic energy of the electron in an orbit of radius r in hydrogen atom is (e = electronic charge [MP PMT 1987]
A.	\[\frac{{{e}^{2}}}{{{r}^{2}}}\]
B.	\[\frac{{{e}^{2}}}{2r}\]
C.	\[\frac{{{e}^{2}}}{r}\]
D.	\[\frac{{{e}^{2}}}{2{{r}^{2}}}\]
Answer» C. \[\frac{{{e}^{2}}}{r}\]

Discussion

9654.	The core of a transformer is laminated so that [CPMT 1985; MP PMT 1994, 2000, 02, 03; BHU 1999]
A.	Ratio of voltage in the primary and secondary may be increased
B.	Rusting of the core may be stopped
C.	Energy losses due to eddy currents may be reduced
D.	Change in flux is increased
Answer» D. Change in flux is increased

Discussion

9655.	If \[{{E}_{0}}\] represents the peak value of the voltage in an ac circuit, the r.m.s. value of the voltage will be [CPMT 1972; MP PMT 1996]
A.	\[\frac{{{E}_{0}}}{\pi }\]
B.	\[\frac{{{E}_{0}}}{2}\]
C.	\[\frac{{{E}_{0}}}{\sqrt{\pi }}\]
D.	\[\frac{{{E}_{0}}}{\sqrt{2}}\]
Answer» E.

Discussion

9656.	According to Bohr's model, the radius of the second orbit of helium atom is [Bihar MEE 1995]
A.	0.53 Å
B.	1.06 Å
C.	2.12 Å
D.	0.265 Å
Answer» C. 2.12 Å

Discussion

9657.	The two metallic plates of radius \[r\] are placed at a distance \[d\]apart and its capacity is \[C\]. If a plate of radius \[r/2\]and thickness \[d\] of dielectric constant 6 is placed between the plates of the condenser, then its capacity will be
A.	\[7C/2\]
B.	\[3C/7\]
C.	\[7C/3\]
D.	\[9C/4\]
Answer» E.

Discussion

9658.	Assertion : Two electric bulbs of 50 and 100 W are given. When connected in series 50 W bulb glows more but when connected parallel 100 W bulb glows more. Reason : In series combination, power is directly proportional to the resistance of circuit. But in parallel combination, power is inversely proportional to the resistance of the circuit.
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

9659.	The ionisation energy of 10 times ionised sodium atom is [DPMT 1991]
A.	13.6 eV
B.	\[13.6\times 11\ eV\]
C.	\[\frac{13.6}{11}eV\]
D.	\[13.6\times {{(11)}^{2}}eV\]
Answer» E.

Discussion

9660.	To deposit one gm equivalent of an element at an electrode, the quantity of electricity needed is [IIT 1984; DPMT 1982; MP PET 1998; MP PMT 1998; 2003]
A.	One ampere
B.	96000 amperes
C.	96500 farads
D.	96500 coulombs
Answer» E.

Discussion

9661.	A bullet of mass 5 g is shot from a gun of mass 5 kg. The muzzle velocity of the bullet is 500 m/s. The recoil velocity of the gun is [DCE 2004]
A.	0.5 m/s
B.	0.25 m/s
C.	1 m/s
D.	Data is insufficient
Answer» B. 0.25 m/s

Discussion

9662.	If the distance between the plates of parallel plate capacitor is halved and the dielectric constant of dielectric is doubled, then its capacity will [MH CET 2003]
A.	Increase by 16 times
B.	Increase by 4 times
C.	Increase by 2 times
D.	Remain the same
Answer» C. Increase by 2 times

Discussion

9663.	Assertion : It is difficult to stop bleeding from a cut in the body at high altitudes. Reason : The atmospheric pressure at high altitude is lesser than the blood pressure.
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

9664.	Weight of a body of mass m decreases by 1% when it is raised to height h above the earth?s surface. If the body is taken to a depth h in a mine, change in its weight is [KCET 2003; MP PMT 2003]
A.	2% decrease
B.	0.5% decrease
C.	1% increase
D.	0.5% increase
Answer» C. 1% increase

Discussion

9665.	Three concurrent forces of the same magnitude are in equilibrium. What is the angle between the forces? Also name the triangle formed by the forces as sides [JIPMER 2000]
A.	\[\text{6}0{}^\circ \] equilateral triangle
B.	\[\text{12}0{}^\circ \] equilateral triangle
C.	\[\text{12}0{}^\circ \], \[\text{3}0{}^\circ \], \[\text{3}0{}^\circ \] an isosceles triangle
D.	\[\text{12}0{}^\circ \] an obtuse angled triangle
Answer» B. \[\text{12}0{}^\circ \] equilateral triangle

Discussion

9666.	1 a.m.u. is equivalent to [UPSEAT 2001]
A.	\[1.6\times {{10}^{-12}}Joule\]
B.	\[1.6\times {{10}^{-19}}Joule\]
C.	\[1.5\,\times {{10}^{-10}}Joule\]
D.	\[1.5\times {{10}^{-19}}Joule\]
Answer» D. \[1.5\times {{10}^{-19}}Joule\]

Discussion

9667.	Which of the following is the longitudinal wave [AFMC 1997]
A.	Sound waves
B.	Waves on plucked string
C.	Water waves
D.	Light waves
Answer» B. Waves on plucked string

Discussion

9668.	If the energy of a hydrogen atom in nth orbit is \[{{E}_{n}}\], then energy in the nth orbit of a singley ionized helium atom will be [BHU 2004]
A.	\[4{{E}_{n}}\]
B.	\[{{E}_{n}}/4\]
C.	\[2{{E}_{n}}\]
D.	\[{{E}_{n}}/2\]
Answer» B. \[{{E}_{n}}/4\]

Discussion

9669.	The absorption transitions between the first and the fourth energy states of hydrogen atom are 3. The emission transitions between these states will be [MP PET 1999]
A.	3
B.	4
C.	5
D.	6
Answer» E.

Discussion

9670.	A ball is released from certain height. It loses 50% of its kinetic energy on striking the ground. It will attain a height again equal to [RPMT 2000]
A.	One fourth the initial height
B.	Half the initial height
C.	Three fourth initial height
D.	None of these
Answer» C. Three fourth initial height

Discussion

9671.	The value of contact angle for kerosene with solid surface. [RPMT 2000]
A.	\[{{0}^{o}}\]
B.	\[{{90}^{o}}\]
C.	\[{{45}^{o}}\]
D.	\[{{33}^{o}}\]
Answer» B. \[{{90}^{o}}\]

Discussion

9672.	A particle carrying a charge equal to 100 times the charge on an electron is rotating per second in a circular path of radius 0.8 metre. The value of the magnetic field produced at the centre will be \[({{\mu }_{0}}=\] permeability for vacuum) [CPMT 1986; KCET 2001; BHU 2001]
A.	\[\frac{{{10}^{-7}}}{{{\mu }_{0}}}\]
B.	\[{{10}^{-17}}{{\mu }_{0}}\]
C.	\[{{10}^{-6}}{{\mu }_{0}}\]
D.	\[{{10}^{-7}}{{\mu }_{0}}\]
Answer» C. \[{{10}^{-6}}{{\mu }_{0}}\]

Discussion

9673.	The atomic weight of silver and copper are 108 and 64. A silver voltameter and a copper voltameter are connected in series and when current is passed 10.8 gm of silver is deposited. The mass of copper deposited will be
A.	6.4 gm
B.	12.8 gm
C.	3.2 gm
D.	10.8 gm
Answer» D. 10.8 gm

Discussion

9674.	In which case does the potential energy decrease [MP PET 1996]
A.	On compressing a spring
B.	On stretching a spring
C.	On moving a body against gravitational force
D.	On the rising of an air bubble in water
Answer» E.

Discussion

9675.	Which of the following gives the value of magnetic field according to, Biot-Savart?s law? [BHU 2000]
A.	\[\frac{i\Delta l\sin \theta }{{{r}^{2}}}\]
B.	\[\frac{{{\mu }_{0}}}{4\pi }\frac{i\Delta l\sin \theta }{r}\]
C.	\[\frac{{{\mu }_{0}}}{4\pi }\frac{i\Delta l\sin \theta }{{{r}^{2}}}\]
D.	\[\frac{{{\mu }_{0}}}{4\pi }i\Delta l\sin \theta \]
Answer» D. \[\frac{{{\mu }_{0}}}{4\pi }i\Delta l\sin \theta \]

Discussion

9676.	Rocket engines lift a rocket from the earth surface because hot gas with high velocity [AIIMS 1998; JIPMER 2001, 02]
A.	Push against the earth
B.	Push against the air
C.	React against the rocket and push it up
D.	Heat up the air which lifts the rocket
Answer» D. Heat up the air which lifts the rocket

Discussion

9677.	Assertion : Friction is a self-adjusting force. Reason : Friction does not depend upon mass of the body.
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

9678.	The wave length of light in visible part \[({{\lambda }_{V}})\] and for sound \[({{\lambda }_{S}})\] are related as [RPMT 1999]
A.	\[{{\lambda }_{V}}>{{\lambda }_{S}}\]
B.	\[{{\lambda }_{S}}>{{\lambda }_{V}}\]
C.	\[{{\lambda }_{S}}={{\lambda }_{V}}\]
D.	None of these
Answer» C. \[{{\lambda }_{S}}={{\lambda }_{V}}\]

Discussion

9679.	If the momentum of a body is increased n times, its kinetic energy increases
A.	n times
B.	2n times
C.	\[\sqrt{n}\]times
D.	\[{{n}^{2}}\] times
Answer» E.

Discussion

9680.	4200 J of work is required for [MP PMT 1986]
A.	Increasing the temperature of 10 gm of water through 10°C
B.	Increasing the temperature of 100 gm of water through 10°C
C.	Increasing the temperature of 1 kg of water through 10°C
D.	Increasing the temperature of 10 kg of water through 10°C
Answer» C. Increasing the temperature of 1 kg of water through 10°C

Discussion

9681.	Assertion : The change in kinetic energy of a particle is equal to the work done on it by the net force. Reason : Change in kinetic energy of particle is equal to the work done only in case of a system of one particle.
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» D. If the assertion and reason both are false.

Discussion

9682.	Assertion : When an object is placed between two plane parallel mirrors, then all the images found are of equal intensity. Reason : In case of plane parallel mirrors, only two images are possible.
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

9683.	Assertion : \[_{Z}{{X}^{A}}\] undergoes \[2\alpha -\]decays. \[2\beta -\] decays and \[2\gamma -\]decays and the daughter product is \[_{Z-2}{{Y}^{A-8}}\]. Reason : In a-decay the mass number decreases by 4 and atomic number decreases by 2. In b- decay the mass number remains unchanged, but atomic number increases by 1 only. [AIIMS 2001]
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

9684.	Assertion : Wire through which current flows gets heated. Reason : When current is drawn from a cell, chemical energy is converted into heat energy.
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» D. If the assertion and reason both are false.

Discussion

9685.	In a circuit, the current lags behind the voltage by a phase difference of \[\pi /2.\] The circuit contains which of the following [AIIMS 2001]
A.	Only R
B.	Only L
C.	Only C
D.	R and C
Answer» C. Only C

Discussion

9686.	Assertion : Aeroplanes are made to run on the runway before take off, so that they acquire the necessary lift. Reason : According to Bernoulli's theorem, as velocity increases pressure decreases and viceversa.
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

9687.	Assertion : The earth?s magnetic field is due to iron present in its core. Reason : At a high temperature magnet losses its magnetic property or magnetism.
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

9688.	Ultrasonic, Infrasonic and audible waves travel through a medium with speeds \[{{V}_{u}},\,{{V}_{i}}\] and \[{{V}_{a}}\] respectively, then [CPMT 1989]
A.	\[{{V}_{u}},\,{{V}_{i}}\] and \[{{V}_{a}}\] are nearly equal
B.	\[{{V}_{u}}\ge {{V}_{a}}\ge {{V}_{i}}\]
C.	\[{{V}_{u}}\le {{V}_{a}}\le {{V}_{i}}\]
D.	\[{{V}_{a}}\le {{V}_{u}}\] and \[{{V}_{u}}\approx {{V}_{i}}\]
Answer» B. \[{{V}_{u}}\ge {{V}_{a}}\ge {{V}_{i}}\]

Discussion

9689.	Assertion : A paramagnetic sample display greater magnetisation (for the same magnetising field) when cooled. Reason : The magnetisation does not depend on temperature.
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» D. If the assertion and reason both are false.

Discussion

9690.	If a steady current of 4 amp maintained for 40 minutes, deposits 4.5 gm of zinc at the cathode and then the electro chemical equivalent will be [MH CET 2003]
A.	\[51\times {{10}^{-17}}\,gm/C\]
B.	\[28\times {{10}^{-6}}\,gm/C\]
C.	\[32\times {{10}^{-5}}\,gm/C\]
D.	\[47\times {{10}^{-5}}\,gm/C\]
Answer» E.

Discussion

9691.	What is the velocity of the bob of a simple pendulum at its mean position, if it is able to rise to vertical height of \[10cm\] (Take \[g=9.8\,m/{{s}^{2}})\] [BHU 2000]
A.	0.6 m/s
B.	1.4 m/s
C.	1.8 m/s
D.	2.2 m/s
Answer» C. 1.8 m/s

Discussion

9692.	Let g be the acceleration due to gravity at earth's surface and K be the rotational kinetic energy of the earth. Suppose the earth's radius decreases by 2% keeping all other quantities same, then [BHU 1994; JIPMER 2000]
A.	g decreases by 2% and K decreases by 4%
B.	g decreases by 4% and K increases by 2%
C.	g increases by 4% and K increases by 4%
D.	g decreases by 4% and K increases by 4%
Answer» D. g decreases by 4% and K increases by 4%

Discussion

9693.	A parallel plate capacitor has plate area A and separation d. It is charged to a potential difference V0. The charging battery is disconnected and the plates are pulled apart to three times the initial separation. The work required to separate the plates is [Kerala PET 2002]
A.	\[\frac{3{{\varepsilon }_{0}}AV_{0}^{2}}{d}\]
B.	\[\frac{{{\varepsilon }_{0}}AV_{0}^{2}}{2d}\]
C.	\[\frac{{{\varepsilon }_{0}}AV_{0}^{2}}{3d}\]
D.	\[\frac{{{\varepsilon }_{0}}AV_{0}^{2}}{d}\]
Answer» E.

Discussion

9694.	Assertion : The minimum number of non coplanar vectors whose sum can be zero, is four. Reason : The resultant of two vectors of unequal magnitude can be 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» D. If the assertion and reason both are false.

Discussion

9695.	Assertion : A body cannot have energy without having momentum but it can have momentum without having energy. Reason : Momentum and energy have same dimensions.
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

9696.	Assertion : Torque on the coil is the maximum, when coil is suspended in a radial magnetic field. Reason : The torque tends to rotate the coil on its own axis.
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

9697.	Assertion : Power developed in circular motion is always zero. Reason : Work done in case of circular motion 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» F.

Discussion

9698.	In an ac circuit, V and I are given by V = 100 sin (100 t) volts, \[I=100\sin \,\left( 100t+\frac{\pi }{3} \right)\,mA\]. The power dissipated in circuit is [MP PET 1989; RPET 1999; MP PMT 1999, 2002]
A.	104 watt
B.	10 watt
C.	2.5 watt
D.	5 watt
Answer» D. 5 watt

Discussion

9699.	In the Bohr model of a hydrogen atom, the centripetal force is furnished by the coulomb attraction between the proton and the electron. If \[{{a}_{0}}\]is the radius of the ground state orbit, m is the mass, e is the charge on the electron and \[{{\varepsilon }_{0}}\]is the vacuum permittivity, the speed of the electron is [CBSE PMT 1998]
A.	0
B.	\[_{7}{{N}^{14}}\]
C.	\[\frac{1}{4}\]
D.	\[\frac{\sqrt{4\pi {{\varepsilon }_{0}}{{a}_{0}}m}}{e}\]
Answer» D. \[\frac{\sqrt{4\pi {{\varepsilon }_{0}}{{a}_{0}}m}}{e}\]

Discussion

9700.	Assertion : When a beetle moves along the sand with in a few tens of centimeters of a sand scorpion the scorpion immediately turn towards the beetle and dashes to it Reason : When a beetle disturbs the sand, it sends pulses along the sands surface one set of pulses is longitudinal while other set is transverse. [AIIMS 2003]
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

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

If the kinetic energy of a body becomes four times of its initial value, then new momentum will [AIIMS 1998; AIIMS 2002; KCET 2000; J & K CET 2004]

The kinetic energy of the electron in an orbit of radius r in hydrogen atom is (e = electronic charge [MP PMT 1987]

The core of a transformer is laminated so that [CPMT 1985; MP PMT 1994, 2000, 02, 03; BHU 1999]

If \[{{E}_{0}}\] represents the peak value of the voltage in an ac circuit, the r.m.s. value of the voltage will be [CPMT 1972; MP PMT 1996]

According to Bohr's model, the radius of the second orbit of helium atom is [Bihar MEE 1995]

The two metallic plates of radius \[r\] are placed at a distance \[d\]apart and its capacity is \[C\]. If a plate of radius \[r/2\]and thickness \[d\] of dielectric constant 6 is placed between the plates of the condenser, then its capacity will be

The ionisation energy of 10 times ionised sodium atom is [DPMT 1991]

To deposit one gm equivalent of an element at an electrode, the quantity of electricity needed is [IIT 1984; DPMT 1982; MP PET 1998; MP PMT 1998; 2003]

A bullet of mass 5 g is shot from a gun of mass 5 kg. The muzzle velocity of the bullet is 500 m/s. The recoil velocity of the gun is [DCE 2004]

If the distance between the plates of parallel plate capacitor is halved and the dielectric constant of dielectric is doubled, then its capacity will [MH CET 2003]

Assertion : It is difficult to stop bleeding from a cut in the body at high altitudes. Reason : The atmospheric pressure at high altitude is lesser than the blood pressure.

Weight of a body of mass m decreases by 1% when it is raised to height h above the earth?s surface. If the body is taken to a depth h in a mine, change in its weight is [KCET 2003; MP PMT 2003]

Three concurrent forces of the same magnitude are in equilibrium. What is the angle between the forces? Also name the triangle formed by the forces as sides [JIPMER 2000]

1 a.m.u. is equivalent to [UPSEAT 2001]

Which of the following is the longitudinal wave [AFMC 1997]

If the energy of a hydrogen atom in nth orbit is \[{{E}_{n}}\], then energy in the nth orbit of a singley ionized helium atom will be [BHU 2004]

The absorption transitions between the first and the fourth energy states of hydrogen atom are 3. The emission transitions between these states will be [MP PET 1999]

A ball is released from certain height. It loses 50% of its kinetic energy on striking the ground. It will attain a height again equal to [RPMT 2000]

The value of contact angle for kerosene with solid surface. [RPMT 2000]

A particle carrying a charge equal to 100 times the charge on an electron is rotating per second in a circular path of radius 0.8 metre. The value of the magnetic field produced at the centre will be \[({{\mu }_{0}}=\] permeability for vacuum) [CPMT 1986; KCET 2001; BHU 2001]

The atomic weight of silver and copper are 108 and 64. A silver voltameter and a copper voltameter are connected in series and when current is passed 10.8 gm of silver is deposited. The mass of copper deposited will be

In which case does the potential energy decrease [MP PET 1996]

Which of the following gives the value of magnetic field according to, Biot-Savart?s law? [BHU 2000]

Rocket engines lift a rocket from the earth surface because hot gas with high velocity [AIIMS 1998; JIPMER 2001, 02]

Assertion : Friction is a self-adjusting force. Reason : Friction does not depend upon mass of the body.

The wave length of light in visible part \[({{\lambda }_{V}})\] and for sound \[({{\lambda }_{S}})\] are related as [RPMT 1999]

If the momentum of a body is increased n times, its kinetic energy increases

4200 J of work is required for [MP PMT 1986]

Assertion : The change in kinetic energy of a particle is equal to the work done on it by the net force. Reason : Change in kinetic energy of particle is equal to the work done only in case of a system of one particle.

Assertion : When an object is placed between two plane parallel mirrors, then all the images found are of equal intensity. Reason : In case of plane parallel mirrors, only two images are possible.

Assertion : Wire through which current flows gets heated. Reason : When current is drawn from a cell, chemical energy is converted into heat energy.

In a circuit, the current lags behind the voltage by a phase difference of \[\pi /2.\] The circuit contains which of the following [AIIMS 2001]

Assertion : Aeroplanes are made to run on the runway before take off, so that they acquire the necessary lift. Reason : According to Bernoulli's theorem, as velocity increases pressure decreases and viceversa.

Assertion : The earth?s magnetic field is due to iron present in its core. Reason : At a high temperature magnet losses its magnetic property or magnetism.

Ultrasonic, Infrasonic and audible waves travel through a medium with speeds \[{{V}_{u}},\,{{V}_{i}}\] and \[{{V}_{a}}\] respectively, then [CPMT 1989]

Assertion : A paramagnetic sample display greater magnetisation (for the same magnetising field) when cooled. Reason : The magnetisation does not depend on temperature.

If a steady current of 4 amp maintained for 40 minutes, deposits 4.5 gm of zinc at the cathode and then the electro chemical equivalent will be [MH CET 2003]

What is the velocity of the bob of a simple pendulum at its mean position, if it is able to rise to vertical height of \[10cm\] (Take \[g=9.8\,m/{{s}^{2}})\] [BHU 2000]

Let g be the acceleration due to gravity at earth's surface and K be the rotational kinetic energy of the earth. Suppose the earth's radius decreases by 2% keeping all other quantities same, then [BHU 1994; JIPMER 2000]

A parallel plate capacitor has plate area A and separation d. It is charged to a potential difference V0. The charging battery is disconnected and the plates are pulled apart to three times the initial separation. The work required to separate the plates is [Kerala PET 2002]

Assertion : The minimum number of non coplanar vectors whose sum can be zero, is four. Reason : The resultant of two vectors of unequal magnitude can be zero.

Assertion : A body cannot have energy without having momentum but it can have momentum without having energy. Reason : Momentum and energy have same dimensions.

Assertion : Torque on the coil is the maximum, when coil is suspended in a radial magnetic field. Reason : The torque tends to rotate the coil on its own axis.

Assertion : Power developed in circular motion is always zero. Reason : Work done in case of circular motion is zero.

In an ac circuit, V and I are given by V = 100 sin (100 t) volts, \[I=100\sin \,\left( 100t+\frac{\pi }{3} \right)\,mA\]. The power dissipated in circuit is [MP PET 1989; RPET 1999; MP PMT 1999, 2002]