12583 + Mcqs in Physics Page 213 McqOptions

10601.	Assertion : In the case of a stationary wave, a person hear a loud sound at the nodes as compared to the antinodes. Reason : In a stationary wave all the particles of the medium vibrate in phase.
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

10602.	In a LCR circuit the pd between the terminals of the inductance is 60 V, between the terminals of the capacitor is 30V and that between the terminals of resistance is 40V. the supply voltage will be equal to ?? [KCET 2004]
A.	50 V
B.	70 V
C.	130 V
D.	10 V
Answer» B. 70 V

Discussion

10603.	Assertion : Thin films such as soap bubble or a thin layer of oil on water show beautiful colours when illuminated by white light. Reason : It happens due to the interference of light reflected from the upper surface of the thin film. [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» D. If the assertion and reason both are false.

Discussion

10604.	Assertion : When a tiny circular obstacle is placed in the path of light from some distance, a bright spot is seen at the centre of shadow of the obstacle. Reason : Destructive interference occurs at the centre of the shadow. [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» D. If the assertion and reason both are false.

Discussion

10605.	Assertion : Coloured spectrum is seen when we look through a muslin cloth. Reason : It is due to the diffraction of white light on passing through fine slits. [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» B. If both assertion and reason are true but reason is not the correct explanation of the assertion.

Discussion

10606.	The turn ratio of a transformers is given as 2 : 3. If the current through the primary coil is 3 A, thus calculate the current through load resistance [BHU 2005]
A.	1 A
B.	4.5 A
C.	2 A
D.	1. 5 A
Answer» D. 1. 5 A

Discussion

10607.	Helium at \[{{27}^{o}}C\] has a volume of 8 litres. It is suddenly compressed to a volume of 1 litre. The temperature of the gas will be \[[\gamma =5/3]\] [CBSE PMT 1993; MP PMT 1999; Pb. PMT 2002]
A.	\[{{108}^{o}}C\]
B.	\[{{9327}^{o}}C\]
C.	\[{{1200}^{o}}C\]
D.	\[{{927}^{o}}C\]
Answer» E.

Discussion

10608.	What vector must be added to the two vectors \[\hat{i}-2\hat{j}+2\hat{k}\] and \[2\hat{i}+\hat{j}-\hat{k},\] so that the resultant may be a unit vector along x-axis [BHU 1990]
A.	\[2\hat{i}+\hat{j}-\hat{k}\]
B.	\[-2\hat{i}+\hat{j}-\hat{k}\]
C.	\[2\hat{i}-\hat{j}+\hat{k}\]
D.	\[-2\hat{i}-\hat{j}-\hat{k}\]
Answer» C. \[2\hat{i}-\hat{j}+\hat{k}\]

Discussion

10609.	Assertion : In projectile motion, the angle between the instantaneous velocity and acceleration at the highest point is\[180{}^\circ \]. Reason : At the highest point, velocity of projectile will be in horizontal direction 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» F.

Discussion

10610.	During an adiabatic process, the pressure of a gas is found to be proportional to the cube of its absolute temperature. The ratio \[{{C}_{p}}/{{C}_{v}}\] for the gas is [AIEEE 2003]
A.	\[\frac{3}{2}\]
B.	\[\frac{4}{3}\]
C.	2
D.	\[\frac{5}{3}\]
Answer» B. \[\frac{4}{3}\]

Discussion

10611.	The ratio of the adiabatic to isothermal elasticities of a triatomic gas is [MP PET 1991]
A.	3/4
B.	4/3
C.	1
D.	5/3
Answer» C. 1

Discussion

10612.	Which of the following is a necessary and sufficient condition for S.H.M. [NCERT 1974]
A.	Constant period
B.	Constant acceleration
C.	Proportionality between acceleration and displacement from equilibrium position
D.	Proportionality between restoring force and displacement from equilibrium position
Answer» E.

Discussion

10613.	A beam of fast moving alpha particles were directed towards a thin film of gold. The parts \[{A}',\ {B}'\]and \[{C}'\]of the transmitted and reflected beams corresponding to the incident parts A, B and C of the beam, are shown in the adjoining diagram. The number of alpha particles in [CPMT 1986, 88; RPET 2000]
A.	\[{B}'\]will be minimum and in \[{C}'\]maximum
B.	\[{A}'\]will be maximum and in \[{B}'\]minimum
C.	\[{A}'\]will be minimum and in \[{B}'\]maximum
D.	\[{C}'\]will be minimum and in \[{B}'\]maximum
Answer» C. \[{A}'\]will be minimum and in \[{B}'\]maximum

Discussion

10614.	Assertion : Three equal charges are situated on a circle of radius r such that they form on equilateral triangle, then the electric field intensity at the centre is zero. Reason : The force on unit positive charge at the centre, due to the three equal charges are represented by the three sides of a triangle taken in the same order. Therefore, electric field intensity at centre 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

10615.	The electrochemical equivalent of a metal is \[3.3\times {{10}^{-7}}\,kg/coulomb\]. The mass of the metal liberated at the cathode when a 3 A current is passed for 2 seconds will be [SCRA 1998; AIEEE 2004; DCE 2005]
A.	\[19.8\times {{10}^{-7}}kg\]
B.	\[9.39\times {{10}^{-7}}kg\]
C.	\[6.6\times {{10}^{-7}}kg\]
D.	\[1.1\times {{10}^{-7}}kg\]
Answer» B. \[9.39\times {{10}^{-7}}kg\]

Discussion

10616.	Two voltameters, one of copper and another of silver, are joined in parallel. When a total charge q flows through the voltameters, equal amount of metals are deposited. If the electrochemical equivalents of copper and silver are \[{{z}_{1}}\] and \[{{z}_{2}}\] respectively the charge which flows through the silver voltameter is [AIEEE 2005]
A.	\[q\frac{{{z}_{1}}}{{{z}_{2}}}\]
B.	\[q\frac{{{z}_{2}}}{{{z}_{1}}}\]
C.	\[\frac{q}{1+\frac{{{z}_{1}}}{{{z}_{2}}}}\]
D.	\[\frac{q}{1+\frac{{{z}_{2}}}{{{z}_{1}}}}\]
Answer» E.

Discussion

10617.	The displacement of an oscillating particle varies with time (in seconds) according to the equation y (cm) = sin \[\frac{\pi }{2}\left( \frac{t}{2}+\frac{1}{3} \right)\]. The maximum acceleration of the particle is approximately [AMU 1995]
A.	\[5.21cm/{{s}^{2}}\]
B.	\[3.62cm/{{s}^{2}}\]
C.	\[1.81cm/s\]
D.	\[0.62cm/{{s}^{2}}\]
Answer» E.

Discussion

10618.	Capacitance of a parallel plate capacitor becomes 4/3 times its original value if a dielectric slab of thickness t = d/2 is inserted between the plates (d is the separation between the plates). The dielectric constant of the slab is [KCET 2003]
A.	8
B.	4
C.	6
D.	2
Answer» E.

Discussion

10619.	If \[\gamma \] denotes the ratio of two specific heats of a gas, the ratio of slopes of adiabatic and isothermal PV curves at their point of intersection is [NCERT 1990; MH CET 1999; MP PMT 2000]
A.	\[1/\gamma \]
B.	\[\gamma \]
C.	\[\gamma -1\]
D.	\[\gamma +1\]
Answer» C. \[\gamma -1\]

Discussion

10620.	Two capillary tubes of same diameter are put vertically one each in two liquids whose relative densities are 0.8 and 0.6 and surface tensions are 60 and 50 dyne/cm respectively Ratio of heights of liquids in the two tubes \[\frac{{{h}_{1}}}{{{h}_{2}}}\]is [MP PMT 2002]
A.	\[\frac{10}{9}\]
B.	\[\frac{3}{10}\]
C.	\[\frac{10}{3}\]
D.	\[\frac{9}{10}\]
Answer» E.

Discussion

10621.	In a copper voltameter experiment, current is decreased to one-fourth of the initial value but it is passed for four times the earlier duration. Amount of copper deposited will be [MP PMT 1993]
A.	Same
B.	One-fourth the previous value
C.	Four times the previous value
D.	\[\frac{1}{16}th\] of the previous value
Answer» B. One-fourth the previous value

Discussion

10622.	In a series LCR circuit, resistance \[R=10\Omega \] and the impedance \[Z=20\Omega .\] The phase difference between the current and the voltage is [KCET (Engg./Med.) 1999]
A.	\[{{30}^{o}}\]
B.	\[{{45}^{o}}\]
C.	\[{{60}^{o}}\]
D.	\[{{90}^{o}}\]
Answer» C. \[{{60}^{o}}\]

Discussion

10623.	In hydrogen atom, if the difference in the energy of the electron in \[n=2\] and \[n=3\] orbits is E, the ionization energy of hydrogen atom is [EAMCET (Med.) 2000]
A.	13.2 E
B.	7.2 E
C.	5.6 E
D.	3.2 E
Answer» C. 5.6 E

Discussion

10624.	Assertion : Hydrostatic pressure is a vector quantity. Reason : Pressure is force divided by area, and force 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» F.

Discussion

10625.	Assertion : Cream gets separated out of milk when it is churned, it is due to gravitational force. Reason : In circular motion gravitational force is equal to centripetal force.
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

10626.	Assertion : If the frequency of alternating current in an ac circuit consisting of an inductance coil is increased then current gets decreased. Reason : The current is inversely proportional to frequency of alternating current.
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

10627.	Assertion : The tangent galvanometer can be made more sensitive by increasing the number of turns of its coil. Reason : Current through galvanometer is proportional to the number of turns of coil.
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

10628.	The frequency of an alternating voltage is 50 cycles/sec and its amplitude is 120V. Then the r.m.s. value of voltage is [BHU 1999; MH CET (Med.) 2001; KCET (Med.) 2001; MH CET 2003]
A.	101.3V
B.	84.8V
C.	70.7V
D.	56.5V
Answer» C. 70.7V

Discussion

10629.	Two charged spheres separated at a distance d exert a force \[F\]on each other. If they are immersed in a liquid of dielectric constant 2, then what is the force (if all conditions are same) [AIIMS 1997; MH CET 2003]
A.	\[\frac{F}{2}\]
B.	\[F\]
C.	\[2F\]
D.	\[4F\]
Answer» B. \[F\]

Discussion

10630.	The current conduction in a discharged tube is due to [CBSE PMT 1999]
A.	Electrons only
B.	+ve ions and electrons
C.	? ve ions and electrons
D.	+ ve ions, ? ve ions and electrons
Answer» E.

Discussion

10631.	A power transformer is used to step up an alternating e.m.f. of 220 V to 11 kV to transmit 4.4 kW of power. If the primary coil has 1000 turns, what is the current rating of the secondary ? Assume 100% efficiency for the transformer [MP PET 1997]
A.	4 A
B.	0.4 A
C.	0.04 A
D.	0.2 A
Answer» C. 0.04 A

Discussion

10632.	The relation between faraday constant F, electron charge e and avogadro number N is [MP PET 1995]
A.	\[F=N/e\]
B.	\[F=Ne\]
C.	\[N={{F}^{2}}\]
D.	\[F={{N}^{2}}e\]
Answer» C. \[N={{F}^{2}}\]

Discussion

10633.	Assertion : The scalar product of two vectors can be zero. Reason : If two vectors are perpendicular to each other, their scalar product will 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» B. If both assertion and reason are true but reason is not the correct explanation of the assertion.

Discussion

10634.	Assertion : At critical temperature, surface tension of a liquid becomes zero. Reason : At this temperature, intermolecular forces for liquids and gases become equal. Liquid can expand without any restriction.
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

10635.	Ultrasonic waves are those waves [CPMT 1979]
A.	To which man can hear
B.	Man can't hear
C.	Are of high velocity
D.	Of high amplitude
Answer» C. Are of high velocity

Discussion

10636.	When an aeroplane attains a speed higher than the velocity of sound in air, a loud bang is heard. This is because [NCERT 1972; J & K CET 2002]
A.	It explodes
B.	It produces a shock wave which is received as the bang
C.	Its wings vibrate so violently that the bang is heard
D.	The normal engine noises undergo a Doppler shift to generate the bang
Answer» C. Its wings vibrate so violently that the bang is heard

Discussion

10637.	A big explosion on the moon cannot be heard on the earth because [CPMT 1972; AFMC 2005]
A.	The explosion produces high frequency sound waves which are inaudible
B.	Sound waves required a material medium for propagation
C.	Sound waves are absorbed in the moon's atmosphere
D.	Sound waves are absorbed in the earth's atmosphere
Answer» C. Sound waves are absorbed in the moon's atmosphere

Discussion

10638.	The action of a nib split at the top is explained by [JIPMER 1999]
A.	Gravity flow
B.	Diffusion of fluid
C.	Capillary action
D.	Osmosis of liquid
Answer» D. Osmosis of liquid

Discussion

10639.	Let the angle between two nonzero vectors \[\overrightarrow{A}\] and \[\overrightarrow{B}\] be 120° and resultant be \[\overrightarrow{C}\]
A.	\[\overrightarrow{C}\] must be equal to \[\|\overrightarrow{A}-\overrightarrow{B}\|\]
B.	\[\overrightarrow{C}\] must be less than \[\|\overrightarrow{A}-\overrightarrow{B}\|\]
C.	\[\overrightarrow{C}\] must be greater than \[\|\overrightarrow{A}-\overrightarrow{B}\|\]
D.	\[\overrightarrow{C}\] may be equal to \[\|\overrightarrow{A}-\overrightarrow{B}\|\]
Answer» D. \[\overrightarrow{C}\] may be equal to \[\|\overrightarrow{A}-\overrightarrow{B}\|\]

Discussion

10640.	The power factor of LCR circuit at resonance is [MP PMT 1991; RPMT 1999; RPET 2001; UPSEAT 1999]
A.	0.707
B.	1
C.	Zero
D.	0.5
Answer» C. Zero

Discussion

10641.	At NTP water boils at 100°C. Deep down the mine, water will boil at a temperature [CPMT 1996]
A.	100°C
B.	> 100°C
C.	< 100°C
D.	Will not boil at all
Answer» C. < 100°C

Discussion

10642.	The radius of the orbital of electron in the hydrogen atom 0.5 Å. The speed of the electron is \[2\times {{10}^{6}}m/s\]. Then the current in the loop due to the motion of the electron is [RPMT 1996]
A.	1 mA
B.	1.5 mA
C.	2.5 mA
D.	\[1.5\times {{10}^{-2}}mA\]
Answer» B. 1.5 mA

Discussion

10643.	A tuning fork of frequency 480 Hz produces 10 beats per second when sounded with a vibrating sonometer string. What must have been the frequency of the string if a slight increase in tension produces lesser beats per second than before [NCERT 1984]
A.	460 Hz
B.	470 Hz
C.	480 Hz
D.	490 Hz
Answer» C. 480 Hz

Discussion

10644.	A tuning fork whose frequency as given by manufacturer is 512 Hz is being tested with an accurate oscillator. It is found that the fork produces a beat of 2 Hz when oscillator reads 514 Hz but produces a beat of 6 Hz when oscillator reads 510 Hz. The actual frequency of fork is [MNR 1979; RPMT 1999]
A.	508 Hz
B.	512 Hz
C.	516 Hz
D.	518 Hz
Answer» D. 518 Hz

Discussion

10645.	When a tuning fork A of unknown frequency is sounded with another tuning fork B of frequency 256 Hz, then 3 beats per second are observed. After that A is loaded with wax and sounded, the again 3 beats per second are observed. The frequency of the tuning fork A is [MP PMT 1994]
A.	250 Hz
B.	253 Hz
C.	259 Hz
D.	262 Hz
Answer» D. 262 Hz

Discussion

10646.	The waves used in telecommunication are
A.	IR
B.	UV
C.	Microwave
D.	Cosmic rays
Answer» D. Cosmic rays

Discussion

10647.	On increasing the plate separation of a charged condenser, the energy [Kerala PMT 2004]
A.	Increases
B.	Decreases
C.	Remains unchanged
D.	Becomes zero
Answer» B. Decreases

Discussion

10648.	Assertion : When range of a projectile is maximum, its angle of projection may be 45° or 135°. Reason : Whether q is 45° or 135°, value of range remains the same, only the sign changes.
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

10649.	Out of gravitational, electromagnetic, Vander Waals, electrostatic and nuclear forces; which two are able to provide an attractive force between two neutrons [NCERT 1978]
A.	Electrostatic and gravitational
B.	Electrostatic and nuclear
C.	Gravitational and nuclear
D.	Some other forces like Vander Waals
Answer» D. Some other forces like Vander Waals

Discussion

10650.	The number of turns in the coil of an ac generator is 5000 and the area of the coil is \[0.25\,{{m}^{2}}\]. The coil is rotated at the rate of 100 cycles/sec in a magnetic field of 0.2\[W/{{m}^{2}}\]. The peak value of the emf generated is nearly [AMU 1995]
A.	786 kV
B.	440 kV
C.	220 kV
D.	157.1 Kv
Answer» E.

Discussion

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

Assertion : In the case of a stationary wave, a person hear a loud sound at the nodes as compared to the antinodes. Reason : In a stationary wave all the particles of the medium vibrate in phase.

In a LCR circuit the pd between the terminals of the inductance is 60 V, between the terminals of the capacitor is 30V and that between the terminals of resistance is 40V. the supply voltage will be equal to ?? [KCET 2004]

Assertion : Thin films such as soap bubble or a thin layer of oil on water show beautiful colours when illuminated by white light. Reason : It happens due to the interference of light reflected from the upper surface of the thin film. [AIIMS 2002]

Assertion : When a tiny circular obstacle is placed in the path of light from some distance, a bright spot is seen at the centre of shadow of the obstacle. Reason : Destructive interference occurs at the centre of the shadow. [AIIMS 2002]

Assertion : Coloured spectrum is seen when we look through a muslin cloth. Reason : It is due to the diffraction of white light on passing through fine slits. [AIIMS 2002]

The turn ratio of a transformers is given as 2 : 3. If the current through the primary coil is 3 A, thus calculate the current through load resistance [BHU 2005]

Helium at \[{{27}^{o}}C\] has a volume of 8 litres. It is suddenly compressed to a volume of 1 litre. The temperature of the gas will be \[[\gamma =5/3]\] [CBSE PMT 1993; MP PMT 1999; Pb. PMT 2002]

What vector must be added to the two vectors \[\hat{i}-2\hat{j}+2\hat{k}\] and \[2\hat{i}+\hat{j}-\hat{k},\] so that the resultant may be a unit vector along x-axis [BHU 1990]

Assertion : In projectile motion, the angle between the instantaneous velocity and acceleration at the highest point is\[180{}^\circ \]. Reason : At the highest point, velocity of projectile will be in horizontal direction only.

During an adiabatic process, the pressure of a gas is found to be proportional to the cube of its absolute temperature. The ratio \[{{C}_{p}}/{{C}_{v}}\] for the gas is [AIEEE 2003]

The ratio of the adiabatic to isothermal elasticities of a triatomic gas is [MP PET 1991]

Which of the following is a necessary and sufficient condition for S.H.M. [NCERT 1974]

The electrochemical equivalent of a metal is \[3.3\times {{10}^{-7}}\,kg/coulomb\]. The mass of the metal liberated at the cathode when a 3 A current is passed for 2 seconds will be [SCRA 1998; AIEEE 2004; DCE 2005]

The displacement of an oscillating particle varies with time (in seconds) according to the equation y (cm) = sin \[\frac{\pi }{2}\left( \frac{t}{2}+\frac{1}{3} \right)\]. The maximum acceleration of the particle is approximately [AMU 1995]

Capacitance of a parallel plate capacitor becomes 4/3 times its original value if a dielectric slab of thickness t = d/2 is inserted between the plates (d is the separation between the plates). The dielectric constant of the slab is [KCET 2003]

If \[\gamma \] denotes the ratio of two specific heats of a gas, the ratio of slopes of adiabatic and isothermal PV curves at their point of intersection is [NCERT 1990; MH CET 1999; MP PMT 2000]

Two capillary tubes of same diameter are put vertically one each in two liquids whose relative densities are 0.8 and 0.6 and surface tensions are 60 and 50 dyne/cm respectively Ratio of heights of liquids in the two tubes \[\frac{{{h}_{1}}}{{{h}_{2}}}\]is [MP PMT 2002]

In a copper voltameter experiment, current is decreased to one-fourth of the initial value but it is passed for four times the earlier duration. Amount of copper deposited will be [MP PMT 1993]

In a series LCR circuit, resistance \[R=10\Omega \] and the impedance \[Z=20\Omega .\] The phase difference between the current and the voltage is [KCET (Engg./Med.) 1999]

In hydrogen atom, if the difference in the energy of the electron in \[n=2\] and \[n=3\] orbits is E, the ionization energy of hydrogen atom is [EAMCET (Med.) 2000]

Assertion : Hydrostatic pressure is a vector quantity. Reason : Pressure is force divided by area, and force is a vector quantity.

Assertion : Cream gets separated out of milk when it is churned, it is due to gravitational force. Reason : In circular motion gravitational force is equal to centripetal force.

Assertion : If the frequency of alternating current in an ac circuit consisting of an inductance coil is increased then current gets decreased. Reason : The current is inversely proportional to frequency of alternating current.

Assertion : The tangent galvanometer can be made more sensitive by increasing the number of turns of its coil. Reason : Current through galvanometer is proportional to the number of turns of coil.

The frequency of an alternating voltage is 50 cycles/sec and its amplitude is 120V. Then the r.m.s. value of voltage is [BHU 1999; MH CET (Med.) 2001; KCET (Med.) 2001; MH CET 2003]

Two charged spheres separated at a distance d exert a force \[F\]on each other. If they are immersed in a liquid of dielectric constant 2, then what is the force (if all conditions are same) [AIIMS 1997; MH CET 2003]

The current conduction in a discharged tube is due to [CBSE PMT 1999]

A power transformer is used to step up an alternating e.m.f. of 220 V to 11 kV to transmit 4.4 kW of power. If the primary coil has 1000 turns, what is the current rating of the secondary ? Assume 100% efficiency for the transformer [MP PET 1997]

The relation between faraday constant F, electron charge e and avogadro number N is [MP PET 1995]

Assertion : The scalar product of two vectors can be zero. Reason : If two vectors are perpendicular to each other, their scalar product will be zero.

Assertion : At critical temperature, surface tension of a liquid becomes zero. Reason : At this temperature, intermolecular forces for liquids and gases become equal. Liquid can expand without any restriction.

Ultrasonic waves are those waves [CPMT 1979]

When an aeroplane attains a speed higher than the velocity of sound in air, a loud bang is heard. This is because [NCERT 1972; J & K CET 2002]

A big explosion on the moon cannot be heard on the earth because [CPMT 1972; AFMC 2005]

The action of a nib split at the top is explained by [JIPMER 1999]

Let the angle between two nonzero vectors \[\overrightarrow{A}\] and \[\overrightarrow{B}\] be 120° and resultant be \[\overrightarrow{C}\]

The power factor of LCR circuit at resonance is [MP PMT 1991; RPMT 1999; RPET 2001; UPSEAT 1999]

At NTP water boils at 100°C. Deep down the mine, water will boil at a temperature [CPMT 1996]

The radius of the orbital of electron in the hydrogen atom 0.5 Å. The speed of the electron is \[2\times {{10}^{6}}m/s\]. Then the current in the loop due to the motion of the electron is [RPMT 1996]

A tuning fork of frequency 480 Hz produces 10 beats per second when sounded with a vibrating sonometer string. What must have been the frequency of the string if a slight increase in tension produces lesser beats per second than before [NCERT 1984]

When a tuning fork A of unknown frequency is sounded with another tuning fork B of frequency 256 Hz, then 3 beats per second are observed. After that A is loaded with wax and sounded, the again 3 beats per second are observed. The frequency of the tuning fork A is [MP PMT 1994]

The waves used in telecommunication are

On increasing the plate separation of a charged condenser, the energy [Kerala PMT 2004]

Assertion : When range of a projectile is maximum, its angle of projection may be 45° or 135°. Reason : Whether q is 45° or 135°, value of range remains the same, only the sign changes.

Out of gravitational, electromagnetic, Vander Waals, electrostatic and nuclear forces; which two are able to provide an attractive force between two neutrons [NCERT 1978]

The number of turns in the coil of an ac­ generator is 5000 and the area of the coil is \[0.25\,{{m}^{2}}\]. The coil is rotated at the rate of 100 cycles/sec in a magnetic field of 0.2\[W/{{m}^{2}}\]. The peak value of the emf generated is nearly [AMU 1995]

The number of turns in the coil of an ac generator is 5000 and the area of the coil is \[0.25\,{{m}^{2}}\]. The coil is rotated at the rate of 100 cycles/sec in a magnetic field of 0.2\[W/{{m}^{2}}\]. The peak value of the emf generated is nearly [AMU 1995]