12583 + Mcqs in Physics Page 188 McqOptions

9351.	Assertion : It is better to wash the clothes in cold soap solution. Reason : The surface tension of cold solution is more than the surface tension of hot solution.
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

9352.	Assertion : Work done by a gas in isothermal expansion is more than the work done by the gas in the same expansion, adiabatically. Reason : Temperature remains constant in isothermal expansion and not in adiabatic expansion.
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

9353.	A wagon weighing 1000 kg is moving with a velocity 50km/h on smooth horizontal rails. A mass of 250 kg is dropped into it. The velocity with which it moves now is [MP PMT 1994]
A.	2.5 km/hour
B.	20 km/hour
C.	40 km/hour
D.	50 km/hour
Answer» D. 50 km/hour

Discussion

9354.	In an LCR series ac circuit, the voltage across each of the components, L, C and R is 50V. the voltage across the LC combination will be [AIEEE 2004]
A.	50V
B.	\[50\sqrt{2}\,V\]
C.	100V
D.	0 V (zero)
Answer» E.

Discussion

9355.	A source of sound gives five beats per second when sounded with another source of frequency \[100\,{{s}^{-1}}\]. The second harmonic of the source together with a source of frequency \[205\,{{s}^{-1}}\] gives five beats per second. What is the frequency of the source [CBSE PMT 1995]
A.	\[105\,{{s}^{-1}}\]
B.	\[205\,{{s}^{-1}}\]
C.	\[95\,{{s}^{-1}}\]
D.	\[100\,{{s}^{-1}}\]
Answer» B. \[205\,{{s}^{-1}}\]

Discussion

9356.	If in a voltaic cell 5 gm of zinc is consumed, then we get how many ampere hours ? (Given that E.C.E. of Zn is \[3.387\times {{10}^{-7}}\] kg/coulomb)
A.	2.05
B.	8.2
C.	4.1
D.	\[5\times 3.387\times {{10}^{-7}}\]
Answer» D. \[5\times 3.387\times {{10}^{-7}}\]

Discussion

9357.	Assertion : For an oscillating simple pendulum, the tension in the string is maximum at the mean position and minimum at the extreme position. Reason : The velocity of oscillating bob in simple harmonic motion is maximum at the mean position.
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

9358.	Assertion : In a S.H.M., kinetic and potential energies become equal when the displacement is \[1/\sqrt{2}\] times the amplitude. Reason : In SHM, kinetic energy is zero when potential energy is maximum.
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

9359.	Assertion : If the amplitude of a simple harmonic oscillator is doubled, its total energy becomes four times. Reason : The total energy is directly proportional to the square of amplitude of vibration of the harmonic oscillator.
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

9360.	There is a \[5\Omega \] resistance in an ac, circuit. Inductance of 0.1H is connected with it in series. If equation of ac e.m.f. is \[5\sin 50t\] then the phase difference between current and e.m.f. is [RPET 2003]
A.	\[\frac{\pi }{2}\]
B.	\[\frac{\pi }{6}\]
C.	\[\frac{\pi }{4}\]
D.	0
Answer» D. 0

Discussion

9361.	The capacitance of an air filled parallel plate capacitor is \[10\mu \mu F\]. The separation between the plates is doubled and the space between the plates is then filled with wax giving the capacitance a new value of\[40\times {{10}^{-12}}farads\]. The dielectric constant of wax is [AMU 1995]
A.	12.0
B.	10.0
C.	8.0
D.	4.2
Answer» D. 4.2

Discussion

9362.	In simple harmonic motion, the ratio of acceleration of the particle to its displacement at any time is a measure of [UPSEAT 2001]
A.	Spring constant
B.	Angular frequency
C.	(Angular frequency)2
D.	Restoring force
Answer» D. Restoring force

Discussion

9363.	Eight small drops, each of radius \[r\] and having same charge \[q\]are combined to form a big drop. The ratio between the potentials of the bigger drop and the smaller drop is [CPMT 1983, 89; MP PMT 1989, 94]
A.	8 : 1
B.	4 : 1
C.	2 : 1
D.	1 : 8
Answer» C. 2 : 1

Discussion

9364.	The size of an atom is of the order of [CPMT 1990; MP PMT 1984; KCET 1994]
A.	\[{{10}^{-8}}m\]
B.	\[{{10}^{-10}}m\]
C.	\[{{10}^{-12}}m\]
D.	\[{{10}^{-14}}m\]
Answer» C. \[{{10}^{-12}}m\]

Discussion

9365.	The meniscus of mercury in the capillary tube is [MP PET/PMT 1988]
A.	Convex
B.	Concave
C.	Plane
D.	Uncertain
Answer» B. Concave

Discussion

9366.	Assertion : If an earth satellite moves to a lower orbit, there is some dissipation of energy but the satellite speed increases. Reason : The speed of satellite is a constant 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» D. If the assertion and reason both are false.

Discussion

9367.	When the current flowing in a circular coil is doubled and the number of turns of the coil in it is halved, the magnetic field at its centre will become [DPMT 2003]
A.	Four times
B.	Same
C.	Half
D.	Double
Answer» C. Half

Discussion

9368.	The decrease in the potential energy of a ball of mass 20 kg which falls from a height of 50 cm is [AIIMS 1997]
A.	968 J
B.	98 J
C.	1980 J
D.	None of these
Answer» C. 1980 J

Discussion

9369.	The potential gradient at which the dielectric of a condenser just gets punctured is called
A.	Dielectric constant
B.	Dielectric strength
C.	Dielectric resistance
D.	Dielectric number
Answer» C. Dielectric resistance

Discussion

9370.	A parallel plate capacitor has an electric field of \[{{10}^{5}}\,V/m\] between the plates. If the charge on the capacitor plate is \[1\mu \,C\], the force on each capacitor plate is [Orissa JEE 2002]
A.	\[0.5\,N\]
B.	\[0.05\,N\]
C.	\[0.005\,N\]
D.	None of these
Answer» C. \[0.005\,N\]

Discussion

9371.	Assertion : In S.H.M., the motion is ?to and fro? and periodic. Reason : Velocity of the particle \[(v)=\omega \sqrt{{{k}^{2}}-{{x}^{2}}}\] (where x is the displacement and k is amplitude) [AIIMS 2002]
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

9372.	The current flowing in a copper voltameter is 3.2 A. The number of copper ions \[(C{{u}^{2+}})\] deposited at the cathode per minute is [Pb. PET 2001]
A.	\[0.5\times {{10}^{20}}\]
B.	\[1.5\times {{10}^{20}}\]
C.	\[3\times {{10}^{20}}\]
D.	\[6\times {{10}^{20}}\]
Answer» E.

Discussion

9373.	A metal plate gets heated, when cathode rays strike against, it due to [CPMT 2000; Pb. PET 2000]
A.	Kinetic energy of cathode rays
B.	Potential energy of cathode rays
C.	Linear velocity of cathode rays
D.	Angular velocity of cathode rays
Answer» B. Potential energy of cathode rays

Discussion

9374.	The kinetic energy of electron in the first Bohr orbit of the hydrogen atom is [Pb. PET 2000]
A.	? 6.5 eV
B.	? 27.2 eV
C.	13.6 eV
D.	? 13.6 eV
Answer» D. ? 13.6 eV

Discussion

9375.	Assertion : Fahrenheit is the smallest unit measuring temperature. Reason : Fahrenheit was the first temperature scale used for measuring temperature. [AIIMS 1999]
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

9376.	Assertion : The absorbance of a perfect black body is unity. Reason : A perfect black body when heated emits radiations of all possible wavelengths at that 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» C. If assertion is true but reason is false.

Discussion

9377.	Assertion : Animals curl into a ball, when they feel very cold. Reason : Animals by curling their body reduces the surface area.
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

9378.	The Bohr model of atoms [CBSE PMT 2004]
A.	Assumes that the angular momentum of electrons is quantized
B.	Uses Einstein?s photo-electric equation
C.	Predicts continuous emission spectra for atoms
D.	Predicts the same emission spectra for all types of atoms
Answer» B. Uses Einstein?s photo-electric equation

Discussion

9379.	Assertion : For the planets orbiting around the sun, angular speed, linear speed, K.E. changes with time, but angular momentum remains constant. Reason : No torque is acting on the rotating planet. So its angular momentum is 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

9380.	Which is not true with respect to the cathode rays [Kerala PET 2001]
A.	A stream of electrons
B.	Charged particles
C.	Move with speed same as that of light
D.	Can be deflected by magnetic fields
Answer» D. Can be deflected by magnetic fields

Discussion

9381.	A gas in an airtight container is heated from 25°C to 90°C. The density of the gas will [BCECE 1997]
A.	Increase slightly
B.	Increase considerably
C.	Remain the same
D.	Decrease slightly
Answer» D. Decrease slightly

Discussion

9382.	Assertion : Compression and rarefaction involve changes in density and pressure. Reason : When particles are compressed, density of medium increases and when they are rarefied, density of medium decreases.
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

9383.	Assertion : Transverse waves travel through air in an organ pipe. Reason : Air possesses only volume elasticity.
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

9384.	Assertion : Ocean waves hitting a beach are always found to be nearly normal to the shore. Reason : Ocean waves are longitudinal waves.
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

9385.	Water waves are [EAMCET 1979; AIIMS 2004]
A.	Longitudinal
B.	Transverse
C.	Both longitudinal and transverse
D.	Neither longitudinal nor transverse
Answer» D. Neither longitudinal nor transverse

Discussion

9386.	Assertion : A hollow metallic closed container maintained at a uniform temperature can act as a source of black body radiation. Reason : All metals acts as a black body [AIIMS 1996]
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

9387.	The velocity of an electron in the second orbit of sodium atom (atomic number = 11) is v. The velocity of an electron in its fifth orbit will be [MP PET 1999]
A.	v
B.	\[\frac{22}{5}v\]
C.	\[\frac{5}{2}v\]
D.	\[\frac{2}{5}v\]
Answer» E.

Discussion

9388.	A solenoid of 1.5 metre length and 4.0 cm diameter posses 10 turn per cm. A current of 5 ampere is flowing through it. The magnetic induction at axis inside the solenoid is [CPMT 1990]
A.	\[2\pi \times {{10}^{-3}}\,tesla\]
B.	\[2\pi \times {{10}^{-5}}\,Tesla\]
C.	\[4\pi \times {{10}^{-2}}\,Gauss\]
D.	\[2\pi \times {{10}^{-5}}\,gauss\]
Answer» B. \[2\pi \times {{10}^{-5}}\,Tesla\]

Discussion

9389.	Assertion : A person sitting in an artificial satellite revolving around the earth feels weightless. Reason : There is no gravitational force on the satellite.
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

9390.	The quantity of heat which crosses unit area of a metal plate during conduction depends upon [MP PMT 1992; JIPMER 1997]
A.	The density of the metal
B.	The temperature gradient perpendicular to the area
C.	The temperature to which the metal is heated
D.	The area of the metal plate
Answer» C. The temperature to which the metal is heated

Discussion

9391.	\[ABC\] is a right angled triangle in which \[AB=3\,cm\] and \[BC=4\,cm\]. And Ð ABC = p/2. The three charges \[+15,\ +12\] and \[-20\,e.s.u.\] are placed respectively on \[A\], \[B\] and \[C\]. The force acting on \[B\] is
A.	\[125\ dynes\]
B.	\[35\ dynes\]
C.	\[25\ dynes\]
D.	Zero
Answer» D. Zero

Discussion

9392.	A body can be negatively charged by [CPMT 1972; AIIMS 1998]
A.	Giving excess of electrons to it
B.	Removing some electrons from it
C.	Giving some protons to it
D.	Removing some neutrons from it
Answer» B. Removing some electrons from it

Discussion

9393.	Assertion : The graph of total energy of a particle in SHM w.r.t., position is a straight line with zero slope. Reason : Total energy of particle in SHM remains constant throughout its motion.
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

9394.	Assertion : The percentage change in time period is 1.5%, if the length of simple pendulum increases by 3%. Reason : Time period is directly proportional to length of pendulum.
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

9395.	Which of the following is different from others [AFMC 1994; CPMT 1999; Pb. PMT 2004]
A.	Velocity
B.	Wavelength
C.	Frequency
D.	Amplitude
Answer» E.

Discussion

9396.	The phase difference between two points separated by 1m in a wave of frequency 120 Hz is \[{{90}^{o}}\]. The wave velocity is [KCET 1999]
A.	180 m/s
B.	240 m/s
C.	480 m/s
D.	720 m/s
Answer» D. 720 m/s

Discussion

9397.	The momentum is most closely related to [DCE 2001]
A.	Force
B.	Impulse
C.	Power
D.	K.E.
Answer» C. Power

Discussion

9398.	A capacitor when filled with a dielectric \[K=3\] has charge \[{{Q}_{0}}\], voltage \[{{V}_{0}}\] and field\[{{E}_{0}}\]. If the dielectric is replaced with another one having \[K=9\] the new values of charge, voltage and field will be respectively
A.	\[3{{Q}_{0}},\ 3{{V}_{0}},\ 3{{E}_{0}}\]
B.	\[{{Q}_{0}},\ 3{{V}_{0}},\ 3{{E}_{0}}\]
C.	\[{{Q}_{0}},\ \frac{{{V}_{0}}}{3},\ 3{{E}_{0}}\]
D.	\[{{Q}_{0}},\ \frac{{{V}_{0}}}{3},\ \frac{{{E}_{0}}}{3}\]
Answer» E.

Discussion

9399.	An alternating e.m.f. of frequency \[v\,\left( =\frac{1}{2\pi \sqrt{LC}} \right)\] is applied to a series LCR circuit. For this frequency of the applied e.m.f. [Roorkee 1999]
A.	The circuit is at resonance and its impedance is made up only of a reactive part
B.	The current in the circuit is in phase with the applied e.m.f. and the voltage across R equals this applied emf
C.	The sum of the p.d.?s across the inductance and capacitance equals the applied e.m.f. which is \[{{180}^{o}}\] ahead of phase of the current in the circuit
D.	The quality factor of the circuit is \[\omega L/R\] or \[1/\omega CR\] and this is a measure of the voltage magnification (produced by the circuit at resonance) as well as the sharpness of resonance of the circuit
Answer» C. The sum of the p.d.?s across the inductance and capacitance equals the applied e.m.f. which is \[{{180}^{o}}\] ahead of phase of the current in the circuit

Discussion

9400.	A 100% efficient transformer has 100 turns in the primary and 25 turns in its secondary coil. If the current in the secondary coil is 4 amp, then the current in the primary coil is [MP PMT 1990]
A.	1 amp
B.	4 amp
C.	8 amp
D.	16 amp
Answer» B. 4 amp

Discussion

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

Assertion : It is better to wash the clothes in cold soap solution. Reason : The surface tension of cold solution is more than the surface tension of hot solution.

Assertion : Work done by a gas in isothermal expansion is more than the work done by the gas in the same expansion, adiabatically. Reason : Temperature remains constant in isothermal expansion and not in adiabatic expansion.

A wagon weighing 1000 kg is moving with a velocity 50km/h on smooth horizontal rails. A mass of 250 kg is dropped into it. The velocity with which it moves now is [MP PMT 1994]

In an LCR series ac circuit, the voltage across each of the components, L, C and R is 50V. the voltage across the LC combination will be [AIEEE 2004]

A source of sound gives five beats per second when sounded with another source of frequency \[100\,{{s}^{-1}}\]. The second harmonic of the source together with a source of frequency \[205\,{{s}^{-1}}\] gives five beats per second. What is the frequency of the source [CBSE PMT 1995]

If in a voltaic cell 5 gm of zinc is consumed, then we get how many ampere hours ? (Given that E.C.E. of Zn is \[3.387\times {{10}^{-7}}\] kg/coulomb)

Assertion : For an oscillating simple pendulum, the tension in the string is maximum at the mean position and minimum at the extreme position. Reason : The velocity of oscillating bob in simple harmonic motion is maximum at the mean position.

Assertion : In a S.H.M., kinetic and potential energies become equal when the displacement is \[1/\sqrt{2}\] times the amplitude. Reason : In SHM, kinetic energy is zero when potential energy is maximum.

Assertion : If the amplitude of a simple harmonic oscillator is doubled, its total energy becomes four times. Reason : The total energy is directly proportional to the square of amplitude of vibration of the harmonic oscillator.

There is a \[5\Omega \] resistance in an ac, circuit. Inductance of 0.1H is connected with it in series. If equation of ac e.m.f. is \[5\sin 50t\] then the phase difference between current and e.m.f. is [RPET 2003]

The capacitance of an air filled parallel plate capacitor is \[10\mu \mu F\]. The separation between the plates is doubled and the space between the plates is then filled with wax giving the capacitance a new value of\[40\times {{10}^{-12}}farads\]. The dielectric constant of wax is [AMU 1995]

In simple harmonic motion, the ratio of acceleration of the particle to its displacement at any time is a measure of [UPSEAT 2001]

Eight small drops, each of radius \[r\] and having same charge \[q\]are combined to form a big drop. The ratio between the potentials of the bigger drop and the smaller drop is [CPMT 1983, 89; MP PMT 1989, 94]

The size of an atom is of the order of [CPMT 1990; MP PMT 1984; KCET 1994]

The meniscus of mercury in the capillary tube is [MP PET/PMT 1988]

Assertion : If an earth satellite moves to a lower orbit, there is some dissipation of energy but the satellite speed increases. Reason : The speed of satellite is a constant quantity.

When the current flowing in a circular coil is doubled and the number of turns of the coil in it is halved, the magnetic field at its centre will become [DPMT 2003]

The decrease in the potential energy of a ball of mass 20 kg which falls from a height of 50 cm is [AIIMS 1997]

The potential gradient at which the dielectric of a condenser just gets punctured is called

A parallel plate capacitor has an electric field of \[{{10}^{5}}\,V/m\] between the plates. If the charge on the capacitor plate is \[1\mu \,C\], the force on each capacitor plate is [Orissa JEE 2002]

Assertion : In S.H.M., the motion is ?to and fro? and periodic. Reason : Velocity of the particle \[(v)=\omega \sqrt{{{k}^{2}}-{{x}^{2}}}\] (where x is the displacement and k is amplitude) [AIIMS 2002]

The current flowing in a copper voltameter is 3.2 A. The number of copper ions \[(C{{u}^{2+}})\] deposited at the cathode per minute is [Pb. PET 2001]

A metal plate gets heated, when cathode rays strike against, it due to [CPMT 2000; Pb. PET 2000]

The kinetic energy of electron in the first Bohr orbit of the hydrogen atom is [Pb. PET 2000]

Assertion : Fahrenheit is the smallest unit measuring temperature. Reason : Fahrenheit was the first temperature scale used for measuring temperature. [AIIMS 1999]

Assertion : The absorbance of a perfect black body is unity. Reason : A perfect black body when heated emits radiations of all possible wavelengths at that temperature.

Assertion : Animals curl into a ball, when they feel very cold. Reason : Animals by curling their body reduces the surface area.

The Bohr model of atoms [CBSE PMT 2004]

Assertion : For the planets orbiting around the sun, angular speed, linear speed, K.E. changes with time, but angular momentum remains constant. Reason : No torque is acting on the rotating planet. So its angular momentum is constant.

Which is not true with respect to the cathode rays [Kerala PET 2001]

A gas in an airtight container is heated from 25°C to 90°C. The density of the gas will [BCECE 1997]

Assertion : Compression and rarefaction involve changes in density and pressure. Reason : When particles are compressed, density of medium increases and when they are rarefied, density of medium decreases.

Assertion : Transverse waves travel through air in an organ pipe. Reason : Air possesses only volume elasticity.

Assertion : Ocean waves hitting a beach are always found to be nearly normal to the shore. Reason : Ocean waves are longitudinal waves.

Water waves are [EAMCET 1979; AIIMS 2004]

Assertion : A hollow metallic closed container maintained at a uniform temperature can act as a source of black body radiation. Reason : All metals acts as a black body [AIIMS 1996]

The velocity of an electron in the second orbit of sodium atom (atomic number = 11) is v. The velocity of an electron in its fifth orbit will be [MP PET 1999]

A solenoid of 1.5 metre length and 4.0 cm diameter posses 10 turn per cm. A current of 5 ampere is flowing through it. The magnetic induction at axis inside the solenoid is [CPMT 1990]

Assertion : A person sitting in an artificial satellite revolving around the earth feels weightless. Reason : There is no gravitational force on the satellite.

The quantity of heat which crosses unit area of a metal plate during conduction depends upon [MP PMT 1992; JIPMER 1997]

\[ABC\] is a right angled triangle in which \[AB=3\,cm\] and \[BC=4\,cm\]. And Ð ABC = p/2. The three charges \[+15,\ +12\] and \[-20\,e.s.u.\] are placed respectively on \[A\], \[B\] and \[C\]. The force acting on \[B\] is

A body can be negatively charged by [CPMT 1972; AIIMS 1998]

Assertion : The graph of total energy of a particle in SHM w.r.t., position is a straight line with zero slope. Reason : Total energy of particle in SHM remains constant throughout its motion.

Assertion : The percentage change in time period is 1.5%, if the length of simple pendulum increases by 3%. Reason : Time period is directly proportional to length of pendulum.

Which of the following is different from others [AFMC 1994; CPMT 1999; Pb. PMT 2004]

The phase difference between two points separated by 1m in a wave of frequency 120 Hz is \[{{90}^{o}}\]. The wave velocity is [KCET 1999]

The momentum is most closely related to [DCE 2001]

A capacitor when filled with a dielectric \[K=3\] has charge \[{{Q}_{0}}\], voltage \[{{V}_{0}}\] and field\[{{E}_{0}}\]. If the dielectric is replaced with another one having \[K=9\] the new values of charge, voltage and field will be respectively

An alternating e.m.f. of frequency \[v\,\left( =\frac{1}{2\pi \sqrt{LC}} \right)\] is applied to a series LCR circuit. For this frequency of the applied e.m.f. [Roorkee 1999]

A 100% efficient transformer has 100 turns in the primary and 25 turns in its secondary coil. If the current in the secondary coil is 4 amp, then the current in the primary coil is [MP PMT 1990]