Physics Questions

A mass of an ideal gas undergoes a reversible isothermal compression Its molecules will then have compared with initial state the same i root mean square velocity ii mean mometum iii mean kinetic energy i ii iii correct 3 ii iii correct 2 i ii correct 4 i correct

A conducting shell of radius R has charge Q Electrostatic force between two parts of the shell which are on either sides of a plane that is at a distance r r R from the centre of the shell is Q Q b 32 R a c 1 7 R Q p 1 32 R R d 2 32 R 327 Q 32 E R 1 5 R 1 1 R

If the door of a refrigerator is kept open then which of the following is ture 1 Room is cooled 2 Room is heated 3 Room is either cooled or heated 4 Room is neither cooled nor heated 2078 C and 127 C It a

Two concentric conducting spheres of radii R and 2R are carrying charges Q and 2Q respectively If the charge on inner sphere is doubled the potential difference between the two spheres will 1 Become two times 2 Become four times 3 Be halved 4 Remain same 2Q 2R 2Q borgo at P as shown in the

14 A ball is dropped from a height of 5m if it rebound upto height of 1 8 m then the ratio of velocities of the ball after and before rebound is A C 3 5 B D 2 4 5

Consider two processes on a system as shown in fig The volumes in the initial states are the same in the two porcesses and the volumes in the final states are also the same Let AW and AW be the work done by the system in the processes A and B respectively 1 AW AW 2 AW AW B T 3 AW AW Nothing can be said about the relation between AW and AW

A block of mass m is moving with initial velocity on horizontal frictionless surface Find the minimum value of velocity v so that the block will complete the vertical circle 1 5Rg m V R 2 3Rg

For an ideal gas the heat capacity at constant pressure is larger than than that at constant volume because 1 positive work is done during expansion of the gas by the external pressure 2 positive work is done during expasion by the gas against external pressure 3 positive work is done during expansion by the gas against intermolecular forces of attraction 4 more collisions occur per unit time when volume is kept constant

Given that the binding energies of the nuclei of element P and Q are Ep and EQ respectively and if two nuclei of element P fuse to give one nucleus of element Q accompanied by the release of energy e find how Ep EQ and e are related to each other A EQ e 2Ep Your Answer B 2EQ e Ep C Ep e 2EQ D 2 Eme Fo

SPECIFIC HEAT CAPACITIES OF GASES When an ideal diatomic gas is heated at constant pressure the fraction of the heat energy supplied which increases internal energy of the gas is 1 2 5 2 3 07 17 3 2 1 4

orrect 2 i ii correct 3 i iii correct The adiabatic bulk modulus of hydrogen gas y 1 4 at NTP is 1 1 x 105 N m 2 1 x 10 5 N m 4 1 4 x 105 N m 3 1 4 N m A given quantity of a gas is at pressure P and absolute temperature T The isothermal bulk modulus c 4 i correct

Three closed vessels A B and C are at the same temperature T and contain gases which obey the Maxwellian distribution of velocities Vessel A contains only O B only N and C a mixture of equal quantities of O and N If the average speed of O molecules in vessel A is V that of the N molecules in vessel B is V the average speed of the O molecules in vessel C will be 1 V V 2 2 V 3 V V 2 4 3KT M EV N 8

N 26 81 In the above problem to be changed by 1 increase by 20 K 3 increase by 20 C 2 53 36 in order to increase the efficiency of the engine by 20 its sink temperature will ha 198k 472 73R 2 decrease by 293 K 4 decrease by 20 C increase the efficiency of 20 its source temperature will have to char

Section A Previous Year Questions AIP sip Two containers of equal volume contain the same gas at pressure p and p and absolute temperature T and T repectively On joining the vessels the gas reaches a common pressure p and common temperature T The ratio p T is equal to RPMT 2009 1 P Pisom P P T P T T T 2 bobaves as an ideal gas 3 P T P T T T 4 27 27 temperature and high pressure RPMT 2009

Ksenia is standing 15 m east of Ella Ksenia fires a paper airplane at 2 m s directly at Ella If Ella immediately scrambles away North at 4 m s at what time will the paper plane be closest to Ella

libih 4 0 5 H A solenoid wound over a rectangular frame If all the linear dimensions of the frame are increased by a facto 3 and the number of turns per unit length remains the same the self inductance increased by a factor of 1 3 2 9 3 27 4 63 7 A coil of inductance 2 H has a current of 5 8 A The flux in weber through the coil is 1 0 29 2 2 9 8 R L D C CIRCUIT Case I Current Growth 3 3 12 4 11 6 sir ye increased by a factor mai confusion ho rhi hai ye smiha do

1 kinetic energy The average momentum 1 temperature 2 momentum 3 density of a molecule in a sample of an ideal gas depends on 2 number of moles 3 volume 4 speed 4 none of thes

The de Broglie wavelength of an electron moving with a velocity 1 5 x 108 ms is equal to that of a photon The ratic of the kinetic energy of the electron to that of the energy of photon is 1 2 2 4 3 4

For the structural analysis of crystals X rays are used because 1 X rays have wavelength of the order of the inter atomic spacing 2 X rays are highly penetrating radiations 3 Wavelength of X rays is of the order of nuclear size 4 X rays are coherent radiations

Two sample A and B are initially kept in the same state The sample A is expanded through an adiabatic process and the sample B through an isothermal process upto the same final volume The final pressures in A and B are p and Pa respectively PAPB 2 PA PB 3 P PB 4 The relation between p and p cannot be deduced Let T and T be the final temperature of the samples A and B respectively in the previous question then NT T 2 T T 3 T T IT cannot be deduced

3 v Vms 4 rms The rms speed of oxygen molecules in a gas is v If the temperature is doubled and the O molecule dissociate into oxygen atoms the rms speed will become Vo 1 V D F U26 1 v 2 v 2 V 2 2 2 4 4v drogen kent at room tempertaure As compared to a hydrogen molecule an

When a spring is subjected to 4N force its length is a metre and if 5N is applied length is b metre If 9N is applied its length is A 4b3a C 5b 4a B 5b a D 5b 2a 135

A solid cylinder of mass M and radius R rolls without 1 slipping down an inclined plane of length L and height h What is the speed of its centre of mass when the cylinder reaches its bottom A 2gh 4 C gh 3 B 3 gh D 4gh

A solenoid wound over a rectangular frame If all the linear dimensions of the frame are increased by a facto libih 4 0 5 H 3 and the number of turns per unit length remains the same the self inductance increased by a factor of 1 3 2 9 3 27 4 63 7 A coil of inductance 2 H has a current of 5 8 A The flux in weber through the coil is 1 0 29 2 2 9 8 R L D C CIRCUIT Case I Current Growth 3 3 12 sir ye increased by a factor mai 4 11 6 confusion ho rhi hai ye smiha do

3 T T 4 any of the three is possibl Suppose a container is evacuated to leave just one molecule of a gas in it Let v and the rms speed of the gas 1 v V TIS V V a rms and v rms rms represent the average speed Vi 2 V VO2 T 4 V is undefined rms If the temperature is doubled and the O molecule dissociate into

When a monochromatic source of light is at a distance of 0 2 m from a photoelectric cell the cut off voltage saturation current are respectively 0 6 V and 18 mA If the same source is placed 0 6 m away from the cell th 1 the stopping potential will be 0 2 V 3 the saturation current will be 6 0 mA 2 the stopping potential will be 1 8 V 4 the saturation current will be 2 0 mA

0 Two spheres of radii R and R respectively are charged and joined by a wire The ratio of electric field of spheres is R 2 1 R2 R 3 R R 2 R 2 4 R R

For a solid with a small expansion coefficient 1 C C R P S 3 C is slightly greater than C P 2 C C R 4 C is slightly less than C temparture change

gas 1 In process AB work done by system is positive 2 In process AB heat is rejected out of the system 3 In process AB internal energy increases P B A T OR internal energy decreases and in process BC internal energy increases

9 Two insulated charged conducting spheres of radii 20 cm and 15 cm respectively and having equal charge of 10 C are connected by a copper wire and then they are separated Hence 1 Both spheres will have equal charges 2 Surface charge density on the 20 cm sphere will be greater than that on the 15 cm sphere 3 Surface charge density on the 15 cm sphere will be greater than that on the 20 cm sphere 4 Surface charge density on the two spheres will be equal

Rohini satellite is at a height of 500 km and Insat B is at a height of 3600 km from surface of earth then relation between their orbital velocity VR V is A VR V C VR V B VR VI D No relation

Suppose we have a small rocket with a full 120 liter fuel tank Fuel with a mass density of 1 kg liter is burned at a steady rate of 2 liters per second and can provide a constant thrust force of 5900 Newtons as it burns The rocket and fuel tank has a mass of 400 kg with no fuel in it The shape design of the rocket causes a resistance proportional to its velocity during flight of 2 v t where v t is in m s and the constant 2 for proportionality of resistance is 2 N m s Give a piecewise function for the force on the rocket over time and use the force equation to find a piecewise function for the acceleration of the rocket over time

A very long wire ABDMNDC is shown in figure carrying current i AB and BC parts are straight long and at right angle At D wire forms a circular turn DMND of radius R AB BC parts are tangential to circular turn at N and D Magnetic field at the center of circle is mathongo mathango mathongs mathon M mathongo mathongo Nhon mathongo mathongo mothongomathongo mathongo mathongo mathongo mathongo BOD mathongamathongo mathongo C athongo mathongo mathongo mathongs mchongo Al mathongo mathongo mathongo mathongo mathongo mathongo mathongo mathongo mathongo mathongo mathongo

To generate a power of 3 2 mega watt the number of fission of U235 per minute is Energy released per fission 200 MeV I eV 1 6 x 10 19 J Question Type Single Correct Type 1 6 x 1018 26x1017 3 1017 4 6x1016

2 If a ladder is not in balance against a smooth vertical wall then it can be made in balance by A Decreasing the length of ladder B Increasing the length of ladder C Increasing the angle of inclination D Decreasing the angle of inclination

A light of amplitude A and wavelength is incident on a metallic surface then saturation current flows is proportional to assume cut off wavelength A A A if2 20 B A if o C A if 20 D A if o

4 Depends both on the intensity and frequency of the incident When stopping potential is applied in an experiment on photoelectric effect no photocurrent is observed This that 1 the emission of photoelectrons is stopped 2 the photoelectrons are emitted but are reabsorbed by the emitter metal 3 the photoelectrons are accumulated near the collector plate 4 the photoelectrons are dispersed from the sides of the apparatus T11

Figure shows the intensity wavelength relations of X rays coming from two different Coolidge tubes The solid curve represents the relation for the tube A in which the potential difference between the target and the filament is V and the atomic number of the target material is Z These quantities are V and Z for the other tube Then A B 1 V V Z ZB Intensity K Wavelength 2 V V Z Z 3 V V Z Z 4 V V Z Z A

mathongo Q28 JEE Main 2020 9 January Evening mathongo mathongo An electron gun is placed inside a long solenoid of radius R on its axis The solenoid has nathongo turns length and carries a current I The electron gun shoots an electron along the radius of the solenoid with speed v If the electron does not hit the surface of the solenoid maximum possible valu mathongo mathongo mathongo mathongo mathongo mathongo mathongo A B C Z S y mathongo mathongo mathongo X mathon of vis all symbols have their standard meaning eponIR 2m eponIR m eponIR nathon c mathon R mathongo mathongo mathongo 2enIR mathongo mathongo mathongo mathonga mathoncomathongo OTTENTO mathongo mathongo mathango mathongo mathongo mathongo mathongo mathongo mathongo mathango

3 three atom either two In a hypothetical atom if transition from n 4 to n 3 produces visible light then the possible transition to obtain infrared radiation is n 5 to n 3 3 n 3 to n 1 2 n 4 to n 2 4 none of these in 13 6eY Hydrogen atoms in the ground state are excited by electromagnetic

When an ideal gas is compressed isothermally then its pressure increases because 1 its potential energy decreases 2 Its kinetic energy increases and molecules move apart 3 its number of collisions per unit area with walls of container increases 4 molecular energy increases

In Bohr s model of hydrogen atom the centripetal force is provided by the Coulomb attraction between the proton and the electron If a is the radius of the ground state orbit m is the mass and e the charge of an electron and is the vacuum permittivity the speed of the electron is 1 zero 2 e e 4 m 3 4ream 4KE a m e ound state to a higher energy state its orbital spe

b Two concentric circular loops of radius 1 cm and 20 cm are placed coaxially i Find mutual inductance of the arrangement ii If the current passed through the outer loop is changed at a rate of 5 A ms find

4 the photoelectrons are disper If the frequency of light in a photoelectric experiment is doubled then stopping potential will be doubled 2 be halved 3 become more than double 4 become less than double

An image of the sun is formed by a lens of focal length 30 cm on the metal surface of a photo electric cell and in produces a current I The lens forming the image is then replaced by another lens of the same diameter but of foca length 15 cm The photoelectric current in this case will be In both cases the plate is kept at focal plane and norm to the axis lens 1 1 2 2 21 3 I 4 41

roton with kinetic energy of 1 MeV moves from south to north It gets an acceleration of 10 2 m s y an applied magnetic field west to east The value of magnetic field Rest mass of proton is moth mathongo mathon mathango 6 x 10 27 Kg 1071 mT

The period of a simple pendulum that is 1 00 m long on another planet is 133s What is the acceleration due to gravity on this planet if the mass of the pendulum bob is 1 5 kg 20 7 m s O24 5 m s O 22 3 m s 26 8 m s

When the 0 05 kg body is in the position shown the torsional spring at O is pretensioned so as to exert a 0 75 N m clockwise moment on the body Determine the force P required to break contact at C Complete solutions for including the effect of the weight Select one a 6 25 N b 5 N c 5 25 N d 6 N A 60 mm C 60 mm ke O 80 mm

22 In an arrangement of two concentric conducting shells with centre at origin and radii a and b a b charges Q and Q are given to inner and outer shell then the potential V at a distance r from the Z origin is r a 1 V 5 3 V kQ kQ a b kQ kQ a r kQ KQ r a Q Q r 2 V 2 4 V k No Ja If the charge

A block placed under the head of the claw hammer as shown greatly facilitates the extraction of the nail If a 50 lb pull on the handle is required to pull the nail calculate the tension T in the nail The contacting surfaces at A are sufficiently rough to prevent slipping Select one a T 250 lb b T 150 lb c T 100 lb d T 200 lb 50 lb 20 F 2 1 8 TH