Physics Questions

1 5 x 1020 2 6 1018 3 62 x 10 0 4 An electron of a stationary hydrogen atom passes from the fifth energy level to the ground level The velocity that the atom acquired as a result of photon emission will be m is the mass of the electron R Rydberg constant and h Planck s constant AIPMT Pre 2012 4 24 hR 25m 2 25 hR 24m 3 24 m 25hR rogon atom jumps from first excited to the ground state 25 m 24hR 4

C 18 The potential on the 2 r r 3 r r 4 r r 1 1 1 C 19 64 charged drops coalesce to from a bigger charged drop The potential of bigger drop will be times that of smaller drop 1 4 2 16 3 64 4 8 tential outside a uniformly charged sphere at a distance r is a being the radius of the sphere

1 2 1 2 3 2 3 4 2 In a sample of radioactive material what percentage of the initial number of active nuclei will during one mean life 1 63 2 50 3 77 4 88 2 RPMT 2014 The angle voluate of photocell is kept fixed The wavelength 2 of the light falling o the cathode is gradually changed RPMT 2014 KF of the photoelectrons emitted varies with as

1 1 Which of the following wavelength is not possible for an X ray tube which is operated at 40 1 0 25 2 0 5 3 0 52 4 IA

3 If E 0 V cannot be zero The electric field in a region is directed outward and is proportional to the distance r from the origin Taking the electric potential at the origin to be zero the electric potential at a distance r 1 is uniform in the region 2 is proportional to r Sis proportional to r 4 increases as one goes away from the origin

3 3 3 A sphere of radius 1 cm has potential of 8000 V The energy density near the surface of sphere will be 2 8 x 10 J m 3 32 J m 42 83 J m 1 64 105 J m X 2 drons assumed spherical each charged to a potential energy U coalesce to a single drop the

4 kinetic energy of emitted photoelectrons decreases If wavelenth of photo is 6000 then its energy will be 3 2 66 eV 2 1 66 eV 1 0 66 eV 4 3 5 eV The energy of an electron in the excited state of H tom is 1 5 eV then according to Bohr model

A positively charged ball hangs from a silk thread We put a positive test charge qo at a point and measure F qo then it can be predicted that the electric field strength E 1 F qo 2 F go 3 F qo 4 Cannot be estimated

10 58 eV In photo emissive cell with exciting wavelength the fastest electron has speed v If the exciting wavelength changed to 32 4 the speed of the fastest emitted electron will be 1 v 3 4 2 2 v 4 3 2 3 less than u 4 3 2 4 greater than u 4 3 2 The rphotoelectric work function for a metal surface is 4 125 eV The cut off wavelength for this surface is

Which of the following statement is true about de Broglie wavelength of moving ball in cricket 1 de Broglie s theory does not apply on such a big body 2 h 2mE 3 E h 2mE

E E 1 R R R 9 3 zero 2 E R www Current through the battery immediately after key K is closed and after a long time interval R ww www R 12 4 B E 2 R R D 2 R E R R E R R 2 R R3 E R

Ub which of the following systems will be radius of the first orbit n 1 be minimur Doubly ionized lithium 2 Singly ionized helium 4 hydrogen atom 3 Deuterium atom

1 proton 2 a particle 3 Neutron 4 B particle When ultraviolet rays incident on metal plate then photoelectric effect does not occur it occur by incidence of 4 Light wave 1 Infrared rays X2 X rays 3 Radio wave which of the following is not the property of cathode rays

If a capacitor of capacitance P 0 05 J 2 1 J 3 0 005 J A capacitor is connected to a cell of emf E having some internal resistance r The potential difference across the 1 cell is E 2 cell is E RPMT 2006 3 capacitor is E 4 capacitor is E dy JEE Main NEET AIIMS 74

In the figure given the potential difference between A and B in steady state will be 1uF 3 F HH 3 F V 2002 ww B 1 F 1 F 100V 2 25 V 1 20 V 3 75 V In the above question the potential difference between B and C in steady state will be 4 100 V 2 25 V 4 75 V 1002 3 50 V joined with capacitors of

Consider a photon gas enclosed in a volume V and in equilibrium at temperature T The photon is a massless particle so that pc a What is the chemical potential of the gas Explain b Determine how the number of photons in the volume depends upon the temperature

1 1 1 eV 2 2 63 eV 3 Work function a metal is 5 26 x 10 18 then its threshold wavelength will be 1 736 7 2 760 7 3 301 4 344 4 A radio station is transmitting the waves of wavelength 300 m Radiation capacity of the transmitter is

1 4 A parallel plate capacitor is charged to 100 volts If a 1 mm thick plate is inserted between the plates of the capacitor distance between the plates required to retain the value of capacitance is 1 6 mm value of dielectric constant of the inserted plate is RPMT 2010 1 5 2 1 25 3 4 4 2 5 ation of four capacitors and their values are given Charge and potential difference acorss 4

J J Thomson s cathode ray tube experiment demonstrated that cathode rays are streams of negatively charged jons 2 all the mass of an atom is essentially in the nucleus 3 the e m of electrons is much greater then the e m of protons 4 the e m ratio of the cathode ray particles changes when a different gas is placed in the discharge aves

3 will remain constant 4 will either increase or decrease A point source causes photoelectric effect from a small metal plate Which of the following curves may represent the saturation photocurrent as a function of the distance between the source and the metal 1 current distance current distance current distance current distance of 106 What is the diameter of the tenth orbit

After charging a capacitor the battery is removed Now by placing a dielectric slab between the plates 4 the potential difference between the plates and the energy stored will decrease but the charge on plates will remain same 2 the charge on the plates will decrease and the potentaial difference between the plates will increase 3 the potential difference between the plates will increase and energy stored will decrease but the charge on the plates will remain same 4 the potential difference energy stored and the charge will remain unchanged

For the circuit shown in the diagram find the value of V V just after closing the switch S 152 www 252 www 1 4 V 2 8 V 352 www H 24V b a 35 www S 3 12 V 4 16 V RPMT 2010

If the shown figure combination of four capacitors and their values are given Charge and potential difference acorss 4 F capacitor will be RPMT 2010 1 600 C 150 Volt 300 ale 20 F CL 4 F 12 F HH 2 300 C 75 Volt 4 F 3 3 800 C 200 Volt 4 580 C 145 Volt illa plate condenser of plate separation d and plate

1 800 V 8 400 V 3 16 A capacitor of 6uF is charged to such an extent that the potential difference between the plates becomes 50 V The work done in this process will be 1 7 5 10 2 J 2 7 5 10 J 3 3 10 J 4 3 10 J dius and having same charge coalesce to form a big drop Capacitance of big drom

PHYSICS Three capacitors of same capacitance are connected in parallel When they are connected to a cell of 2 volt total charge of 1 8 C is accumulated on them Now they are connected in series and then charged by the same cell The total charge stored in them will be 1 1 8 C 2 0 9 C 3 0 6 C The equivalent capacitance between A and B of the combination shown in the fir 40 2 C CENY

1 10 2 eV An energy of 24 6 eV is required to remove one of the electrons from a neutral helium atom The energy In required to remove both the electrons from a neutral helium atom is 1 38 2 2 49 2 3 51 8 4 79 0

The stopping potential necessary to reduce the photoelectric current to zero 1 is directly proportional to wavelength of incident light 2 uniformly increases with the wavelength of incident light 3 directly proportional to frequency 4 uniformly increases with the frequency

1 2eV m 2 2eV m the The 21 cm radio wave emitted by hydrogen in interstellar space is due to ter interaction called teh hyperfine interaction natomic hydrogen The energy of the emitted wave is nearly 1 10 7 J 2 IJ 3 7 10 J 4 10 J U Rohr s model of a hydrogen atom the enctripetal force is furnished by the Coulomb attraction between te rhit mis the mass and e is the charge on the electre

In the given figure the capacitance of each capacitor is C then the effective capacitance between A and B will be 1 C 2 2 C A B C C C C 3 2C C 4 6C

n resistances each of resistance R are joined with capacitors of capacity C each and a battery of emf E as shown in the figure In steady state condition ratio of charge stored in the first and last capacitor is 1 n R R 2 n 1 n 1 C 3 n 1 n 1 4 1 1

Draw a graph of conductivity vs temperature for a metal a semiconductor and a superconductor O The resistance R experienced by an electrical wire of pure copper can be ad using the formula below

4 remains decreases increases 4 decreases remains unchanged A parallel plate condenser is connected to a battery of c m f 4 volt If a plate of dielectric constant 8 is inserted int then the potential difference on the condenser will be 1 1 2 V 2 2V 9 4V 4 32V vill b

photoelectrons emitted from a metal surface The 1 Are all at rest 2 Have the same kinetic energy 3 Have the same momentum 4 Have speeds varying from zero up to a certain maximum value

A block of mass 1 kg is horizontally thrown with velocity of 10 m s on a stationary long rough plank whose coefficient of kinetic friction is 0 25 After what time block will come to

4 Maximum when the sheet is just near the ve plate The value of a capacitor formed by a thin metallic foil is 2 uF The foil is folded with a layer of paper having a thick ness of 0 015 mm The dielectric constant of the paper is 2 5 and its breadth is 40 mm The length of the foil used is 4 33 9 m 3 13 4 mm 1 0 34 m 2 1 33 m allol plote air capacitor is charged by connecting its plates to a battery Without disconnecting the battery a dielectric

Problem 2 A line charge with linear charge density 10 2 C m passes through the center of a sphere If the flux through the surface of the sphere is 1 13 10 3 Vm what is the radius R of the sphere

A network of four capacitors of capacity equal to C C C 2C C 3C and C 4C are connected to a battery as shown in the figure The ratio of the charges on C an C is AIPMT 2005 22 C H C C HH C 7

Two particles are projected simultaneously with different speed from same point in a plane as shown in figure The incorrect statement is 4 m s y 53 3 m s Their relative acceleration is zero Their relative velocity is constant Their relative velocity is along horizontal direction Their relative velocity is along vertical direction

If the two plates of the charged capacitor are connected by a wire then 1 potential will become infinite 3 capacitor will get discharged 2 charge will become infinite 4 charge will become double that of earl Now connecting it in parall

A sheet of aluminium is inserted in the air gap of a parallel plate capacitor without touching any of the two plates of the capacitor The capacitance of the capacitor is 1 Invariant for all positions of the sheet 2 Maximum when the sheet is midway between the 2 plates 3 Maximum when the sheet is just near the ve plate 4 Maximum when the sheet is just near the ve plate The foil is folded with a laver of paper having a thick

The radius of the circular plates of a parallel plate capacitor is R Air is dielectric medium between the plates If the capacitance of the capacitor is equal to the capacitance of a sphere of radius R then the distance between the plates is R 4 2 R 2 3 R 4 2R

B When you have read the question and need time to solve it When you have received the question and you have to go throu it before answering When you have solved the question and need to send it to the student

4 Have speeds varying from zero up to 50 of the X rays coming from a Coolidge tube is able to pass through a 0 1 mm thick aluminum foil The potential difference between the target and the filament is increased The thickness of aluminimum foil which will allow 50 c the X ray to pass through will be 1 zero 2 0 1 mm 3 0 1 mm 4 0 1 mm antiol as a function of frequency of incident radiation is plotted for two different photo elect

The potential of earth is zero because it is 1 unchanged 3 an object of infinite capacitance two plates of the charged capacitor are connected by a wire then 2 an object of zero capacitanc 4 having infinite charge

You have already picked the doubt whats your immediate next step B D If the question and its solution is lengthy I will use Need time to solve template If the solution is not going to take much time I will start solving it immediately If any part of the question is not clear I will immediately ask the student to explain it before solving All of the above options are true

29 If a uniformly charged spherical shell of radius 10 cm has a potential V at a point distant 5 cm from its centre the the potential at a point distant 15 cm from the centre will be 1 V 3 2 2V 3 3 2 V 3 Particle 4 3V

Suppose we fill a glass flask with a liquid whose real expansivity is three times the linear expansivity of glass On heating Question Type Single Correct Type 1 2 3 4 The liquid level will increase The liquid level will decrease The liquid level will exactly remain same The liquid level will approximately

The plates of a capacitor of capacitance 10 uF charged to 60 C are joined together by a wire of resistance 100 0 then i the charge on the capacitor in the circuit at t 0 is 1 120 C 2 60 C 3 30 C ii the charge on the capacitor in the circuit at t 100 us is 1 120 C 2 60 C 3 22 C iii the charge on the capacitor in the circuit at t 1 0 ms is 2 60 C 1 0 003 LC 3 44 C 4 44 C 4 18 C 4 18 C

The position x of a particle with respect to time along x axis is given by equation x 91 1 where x is in meter and tin second What will be position of particle when it achieves maximum speed along ve x axis 54 m 42 m 32 m 46 m

A capacitor of capacitance 500uF is charged at the rate of 100 C s The time in which the potential difference become 20 V is 100 s 2 50 s 3 20 s 4 10 s aloter