Physics Questions

Electrons used in an electron microscope are accelerated by a voltage of 25 kV If the voltage is increased to 100 kV then the de Broglie wavelength associated with the electrons would AIPMT Prelims 2011 1 Increase by 4 times 2 Increase by 2 times 3 Decrease by 2 times 4 Decrease by 4 times

A solid cylinder begins to rolls down on 30 incline of length 9 m without slipping The speed of centre of mass at the bottom of plane is 1 3g 2 g 3 2 g 4 6g X The pres where F drawn o of initial tank will 110

49 A telescope whose objective lens has an aperture of 1mm for the wavelength of light 500A then limit of resolution of the telescope is 1 2 1 x 104 rad 3 5 1 x 104 rad 2 4 1 104 rad 4 6 1 x 10 rad 50 A ray of light is incident on a glass plate at the polarising angle 57 Then Given tan57

A certain metallic surface is illuminated with monochromatic light of wavelength The stopping potential for photo electric current for this light is 3V If the same surface is illuminated with light of wavelength 27 the stopping potential is V The threshold wavelength for this surface for photo electric effect is AIPMT 2015 1 2 6 3 41 2 62 4 2 4

A disc of radius 50 cm is rolling purely on a horizontal ground with velocity of ceutre of mass 10 mg 10 ms What is the instantaneous speed of point P as shown in diagram 10 ms O P A 10 ms B 10 2ms C 20 ms D 5 ms

A DIOCK OI ontal table surface at initial speed vo It then moves smoothly onto a sloped wedge of mass M The wedge can also move on the table surface Assume that everything moves without friction Which of the following statement s is are correct m V M COM of the system always moves rightward COM of the system moves upwards for some time Speed of M always increases during contact with m Speed of COM of the system is always constant

When a spectral line of wavelength 0 59 m is observed in the directions to the opposite edges of the solar disc along its equator there is a difference in wavelengths equal to 8 0 pm Find the period of the Sun s revolution about its own axis in days

3 A conducting circular ring of radius 1 m is given a positive charge 1 105 C A particle of mass 0 9 gm and carrying a negative charge of magnitude 1 106 C is placed on the axis at a distance of 1 cm from the center of the ring Show that the motion of negatively charged particle is almost simple harmonic Calculate its time period of oscillation

Two radiations of photons energies 1 eV and 2 5 eV successively illuminate a photosensitive metallic surface of work function 0 5 eV The ratio of the maximum speeds of the emitted electrons is AIPMT Mains 2012 2 1 2 4 1 5 1 1 4 3 1 1

connected by ideal strings and are being pulled along a horizontal frictionless table by a constant horizontal force F refer diagram T 120 N A B120 The magnitude of F is 120 N Which of the following statements are correct Tension in the string connecting blocks A and B is 60 N The magnitude of F is 180 N C Acceleration of blocks is 4 m s F

Current I is uniformly distributed across cross sectional area of hollow cylindrical conductor of inner radius R and outer radius 3R Magnetic field at distance 2R from axis of cylindrical conductor is 2 1 MoI 2TR 5 I 36TR 3 Ho I 32 R 4 3 oI 32 R

3 3cm 6cm 4 3cm 7 5cm In young s double slit experiment the two slits are d distance apart Interference pattern is observed on a screen at a distance D from the slits A dark fringe is observed on the screen directly opposite to one of the slit The wavelength of light may be

temperature above its Curie temperature the material 1 Is permanently magnetized 2 Remains ferromagnetic 3 Behaves like a diamagnetic material

Light of two different frequencies whose photons have energies 1 eV and 2 5 eV respectively illuminate a metallic surface whose work function is 0 5 eV successively Ratio of maximum speeds of emitted electrons will be 1 1 5 3 1 2 AIPMT Prelims 2011 2 1 4 4 1 1

If a bowler is bowling at the speed of 120 km per hour and the mass of the ball is 100 g and boundary 64 m awa y Then find the force required by the batsman to hit the ball by which it wil I reach the boundary In newton sol ve using Newton laws of motion

For a small circular current loop magnitude of magnetic field in the plane of the loop at a point distant x from centre of loop x R and magnetic dipole moment of loop is m IA is 1 B Hom X Ho m 4 x 2 B 3 B 4 B Mo 2m 4 x Hom R 21x 3

When the energy of the incident radiation is increased by 20 the kinetic energy of the photoelectrons emitted from a metal surface increased from 0 5 eV to 0 8 eV The work function of the metal is AIPMT 2014 1 0 65 eV 2 1 0 eV

18 An infinite number of identically charged bodies are kept along the x axis at points x 0 1m 2m 4m 8m 16m and so on All other charges repel the charge at the origin witha force of 1 2 N Find magnitude of each charge a 9 C TO C c 11 C d 12 C

In the given circuit resistance of potentiometer wire AB is 1022 and its length is Im Rest of quantities are shown in figure The null point will be at a separation m from point A then find value of x 8 3 1 5v 0 30 ww 1 20 1502 www B

Consider the situation shown in figure The elevator is going up with an acceleration of 2 00 m s and the focal length of the mirror is 12 0 cm All the surfaces are smooth and the pulley is light The mass pulley system is released from rest with respect to the elevator at t 0 when the distance of B from the mirror is 42 0 cm Find the distance between the image of the block B and the mirror at t 0 200 s Take g 10 m s Distance is given in cm A M B a 2 00 m s 2

A 200 W sodium street lamp emits yellow light of wavelength 0 6 m Assuming it to be 25 efficient in converting electrical energy to light the number of photons of yellow light it emits per second is AIPMT Prelims 2012 2 3 1019 4 6 1018 1 62 1020 3 1 5 1020

In a non uniform circular motion of a particle Angular acceleration of perpendicular to acceleration of particle particle is Angular acceleration of perpendicular to velocity of particle particle is Angular velocity of particle is perpendicular to acceleration of particle Angular velocity of particle is perpendicular to velocity of particle

Monochromatic radiation emitted when electron on hydrogen atom jumps from first excited to the ground state irradiates a photosensitive material The stopping potential is measured to be 3 57 V The threshold frequency of the material is 1 1 6 x 1015 Hz 3 4 x 1015 Hz AIPMT Prelims 2012 2 2 5 x 1015 Hz 4 5 x 1015 Hz

A particle is projected from ground at an angle 0 At a certain instant the velocity vector v of particle makes an angle a with horizontal dv dt g modulus of a v dt g sin a Tangential acceleration has magnitude of g sin a Normal radial acceleration CC O

SolveLancer Test Density of diatomic gas is 0 800 kgm at temperature 400 K and pressure 4 atm Find the specific heat of the gas at constant volume SolveLancer Test a 2 125 x 104 J kg K b 1 25 x 104 Jkg K c 1 125 x 104 Jkg K 1 d 3 125 x 104 Jkg K

A thin uniform rod of mass m and length is hanging freely at rest from its topmost point and is free to rotate about its upper end When it is at rest it receives an impulse J at its lowest point normal to its length Immediately after O The angular momentum of the rod is J 3J 0 Angular velocity of the rod is me 0 The kinetic energy of the rod is 3J 2m 3J 0 The linear velocity of the midpoint of the rod is 2m

Choose the incorrect statements DIf linear momentum of system is conserved then angular momentum of system must be also conserved If angular momentum conserved then angular velocity must be also conserved about the same axis DIf net torque about any axis is zero then force must also be zero If net force on a body is zero torque about an axis through COM may be non zero

2 A particle of mass m is placed on the axis of a ring of radius R and mass M at a point P as shown in figure Gravitational force on the particle due to ring will be JK 3 1 3GMm 8R 2 FGMm M R 3 R 2 m SP GMm 4R GMm F GR

bomb is projected vertically upward from ground At heighest point it explodes in two parts having mass ratio 1 2 Both the part lanc n ground at equal distance from point of projection at on interval of 4 sec If both parts land on ground at time t and t2 after explosion 1 1 nd 5

Three equal negative charges q each form the vertices of an equilateral triangle A particle of mass m and a positive charge q2 is constrained to move along a line perpendicular to the plane of triangle and through its centre which is at a distance from each of the negative charges as shown in the figure The whole system is kept in gravity free space Find the time period of vibration of the particle for small displacement from equilibrium position 9 9 A 4neomr 239192 B 2 C 2T D 2T Teomr 39192 Solution A 4 eomr 9192 3 omr 49192 Let the charge q2 is moved a distance a perpendicular to the plane of the triangle a a charge q2 from one of the vertices of triangle R 2 Let the angle between a and R is 0 Net force perpendicular to plane of triangle is 3F cos 0 Here 3kq192 x Fuet 3F cos 0 R2 R here ve sign indicates that force is opposite to displacement r a T 2TA 9 3kq192x m x 72 3 59142 4 com3 4 Mr 39192 Distance of x ma 2 as for small a i e

1311 is an isotope of lodine that decays to an isotope of Xenon with a half life of 8 days A small amount of a serum labelled with 131 is injected into the blood of a person The activity of the amount of 131 linjected was 2 4 x 105Becquerel Bq It is known that the injected serum will get distributed uniformly in the blood stream in less than half an hour After 11 5 hours 2 5 ml of blood is drawn from the person s body and gives an activity of 115 Bq The total volume of blood in the person s body in liters is approximately you may use et 1 x for x 1 and In 2 0 7

Plz explain me this mam ne bola tha agar charge jyda hog a tohh deflect jyda krega due to replusion so deflection an gle bhi bdega so no of particle deflected bhi bdenge But unhone yeah bhi toh bola sintheta 2 ke liye ki agar th eta jyda hoga mtlb larger deflection aur larger deflection p e number of particle kam hunge yeah kaise plz koi explain kr do the sich L while ho of partich defected at 0 r N 0 x chary N 0 X Xe Dayle on the needles Kinetic every y of projectile 2 N O 2 074

40 A plastic disc of radius R has a charge q uniformly distributed over its surface If the disc is rotated with a frequency about its axis then the magnetic moment of the disc is given by A B C qR f D none of these Hofq R ZqR 2

The angle of declination is defined as the angle between the geographic north and 1 South shown by a compass needle 2 Geographic south 3 North shown by a compass needle 4 Magnetic needle of dip circle

A small block of mass m is moving on a horizontal table surface at initial speed vo It then moves smoothly onto a sloped wedge of mass M The wedge can also move on the table surface Assume that everything moves without friction Which of the following statement s is are correct m Vo COM of the system always moves rightward COM of the system moves upwards for some time Speed of M always increases during contact with m Speed of COM of the system is always constant M

45 A stream of electrons is projected horizontally to the right A straight conductor carrying current is supported parallel to the electron stream and above it If the current in the conductor is from left to right then what will be the effect on the electron stream only due to magnetic effect A The electron stream will be speeded towards the right B The electron stream will be retarded C The electron stream will be pulled upwards D The electron stream will be pulled downwards

A straight wire carrying a current of 12A is bent into a semicircular loop of radius 2 0 cm What will be magnetic field at the centre of the semicircular loop 1 B 1 9 x 104 TO 2 B 1 9 x 10 TO 3 B 1 9 x 10 TO 4 B 1 9 x 10 TO

A particle of charge q and mass m is moving along the x axis with a velocity v and enters a region of electric field E and magnetic field B as shown in figure below For which figure the net force on the charge may be zero 1 3 gv 9 V MAJOR SRG AC E B E B 2 4 gov 9V B AY E E B X

1 Two ships A and B are at rest on still water of a sea Ship B is at a position 80 km east and 150 km north of A Ship B starts moving with a velocity of 10 km hr towards west and at the same time ship A starts moving with velocity components 30 km hr and 50 km hr along east and north respectively After what time interval the distance between two ships will be the minimum

20 The siren of a police car emits a pure tone at a frequency of 1125 Hz Find the frequency that you would perceive in your car under the following circumstances a Your car at rest police car moving toward you at 29 m s b Police car at rest your car moving toward it at 29 m s c You and the police car moving toward one another at 14 5 m s d You moving at 9 m s police car chasing behind you at 38 m s

In YDSE distance between two slits is 1 mm distance of screen from two slits is 4 m If light of wave length 500 nm is used in experiment then what is distance in mm between 3rd maxima and 5th minima formed on same side of the central maxima

An electron moves with a speed of 2 10 m s along the x direction in a magnetic field B 1 4j 3k tesla The magnitude of the force in newton experienced by the electron is the charge on electron 1 6 10 C 1 1 18 10 13 2 1 28 x 10 13 3 1 6 10 13 4 1 72 10 13

Figure 38 W14a shows a conducting circular loop of radius a placed in a uniform perpendicular magnetic field B A metal rod OA is pivoted at the centre O of the loop The other end A of the rod touches the loop The rod OA and the loop are resistanceless but a resistor having a resistance R is connected between 0 and a fixed point C on the loop The rod OA is made to rotate anticlockwise at a small but uniform angular speed a by an external force Find a the current in the resistance R and b the torque of the external force needed to keep the rod rotating with the constant angular elocity w A E Boa 2 X X R 240 0 Cx a 3 A X R OF HA b

35 A charged particle moves insides a pipe which is my bent as shown in figure If R then force qB exerted by the pipe on charged particle at P is neglect gravity A toward center C zero B away from center D none of these 9 V B

19 A glider of mass m 1 25 kg moves with a velocity of 3 62 m s on a frictionless level air track and collides with a second glider of mass m2 2 30 kg that is initially at rest After the collision the first glider is found out be moving at 1 07 m s in a direction opposite to that of its initial motion What is the velocity of m2 after the collision

Least possible value of correction factor for i kinetic energy is zero ii kinetic energy is 1 momentum is zero iii iv momentum is 1 sd The correct statements are a i and iii b c ii and iii i and iv ii and iv

43 A particle of mass 2 x 10 kg moves horizontally between two horizontal plates of a charged parallel plate capacitor between which there is an electric field of 200 NC acting upward And magnetic induction of 2 0 T is applied at right angles to the electric field in and direction normal to both E and v If g is 9 8 ms and the charge on the particle is 10 C then find the velocity of charge particle so that it continues to move horizontally A 2 ms B 20 ms C 0 2 ms D 100 ms

hui hai bucket nhi laga hai Bucket ke khud ke hee weight ke kaaran rope toot gyi aur niche gir gyi Aur girne ki awaaz bhi aai Yeh elastic collision hai ya inolastic allicion pe koi external force

44 Current of 10 ampere and 2 ampere are passed through two parallel wires A and B respectively in opposite directions If the wire A is infinitely long and the length of the wire B is 2 m the force on the conductor B which is situated at 10 cm distances from A will be A 8 x 10 N B 4 x 105 N C 8m x 107 N D 4 x 107 N

A current of 5 ampere is flowing in a wire of length 1 5 metres A force of 7 5 N acts on it when it is placed in a uniform magnetic field of 2 Tesla The angle between the magnetic field and the direction of the current is 1 30 3 60 2 45 4 90