Physics Questions

2 A1 Infinitely long hollow conducting cylinder with inner radius R 2 and outer radius R carries a uriform current density along its length The magnitude of the magnetic field B as a function of the radial distance r from the axis is best represented by A B C B B R 2 R R 2 R D B B R 2 R R 2 R

View In English A particle describes a horizontal circle in a conical funnel whose inner surface is smooth with speed of 0 5 m s What is the height of the plane of circle from vertex of the funnel 1 2 3 4 Correct Answer 4 Status unattempted 0 25cm 2cm 4cm 2 5cm

The diameter of a brass metal bob is fo und to be as 1 92cm The mass of the Bob is measured to be 29 150g The de nsity of material in kilogram per metre cube to correct number of significant fi qures is

Q No 20 View In English Assuming human pupil to have a radius of 0 25cm and a comfortable viewing distance of 25cm the minimum separation between two objects that human eye can resolve at 500 n wavelength is 1 2 3 Correct Answer 4 Status unattempted 100 m 300 m 1 m 30 5 m V

89 A ball of mass m is dropped What is the formula for the impulse exerted on the ball from the instant it is dropped to an arbitrary time later Ignore air resistance 90 Repeat the preceding problem but including a drag force due to air of fdrag bv

3 Three equal impedances each having a resistance of 2502 and reactance of 400 an connected in star to a 400V 3 phase 50Hz system Calculate i the line curren ii power factor and current iii power consumed

For the transistor circuit shown below if 100 voltage drop between emitter and base is 0 7 V then value of VCE will be 2 3 4 2V 5 V 13 V 15 V Correct Answer 3 Status unattempted Add to Do 8 6 k SV 100 2 E 18 V Vi

14 The displacement of a particle executing periodic motion is given as y 4 sin 1000f cos t This displacement equation may be considered as superposition of 1 Two waves 3 Four waves 2 Three waves 4 Five waves

9 Two large vertical and parallel metal plates having a separation of 1 cm are connected to a DC voltage source of potential difference X A proton is released at rest midway between the two plates It is found to move at 45 to the vertical JUST after release Then X is nearly A 1 x 105 v B 1 1077 V D 1x 10 0 V C 1 x 10 v 9

4 A flux of 25mWb links with a 1500 turn coil when a current of 34 passes through the coil Calculate a the inductance of the coil b the energy stored in the magnetic field and c the average e m f induced if the current falls to zero in 150ms

he po of time is given by R 4 sin 2nt i 4 cos 2nt j Where R is in meters t is in seconds and i and denote unit vectors along x and y directions respectively Which one of the following statements is wrong for the motion of particle 1 Path of the particle is a circle of radius 4 meter 2 Acceleration vectors is along R 3 Magnitude of acceleration vector is R where v is the velocity of particle 4 Magnitude of the velocity of particle is 8 meter second

The current i at time t 0 and t respectively for the given circuit is B 18E 55 5E 18 5E 18E 18 55 5E 10E 18 33 10 5E 50 10 Ai 50 E 402 mooooo L

The figure shows a system consisting of i a ring of outer radius 3R rolling clockwise without slipping on a horizontal surface with angular speed and ii an inner disc of radius 2R rotating anti clockwise with angular speed w 2 The ring and disc are separated by frictionless ball bearings The system is in the x z plane The point P on the inner disc is at a distance R from the origin where OP makes an angle of 30 with the horizontal Then with respect to the horizontal surface 20 3R Z 2R 30 A the point O has a linear velocity 3Rwi B the point P has a linear velocity R C the point P has a linear velocity 13 4 D the point P has a linear velocity 3 Rwi Rai 3 4 Rak 3 Rak 4 3 3 Ravi Rask 4

galvanometer Now the first battery E is replaced by second battery E for working by making K open and K closed The galvanometer gives the null deflection at J The value of is E where a E2 wwwwww Rh K E B 3 E 20 cm J m K J 60 cm Answer K

Find the maximum kinetic energy in eV of the photoelectron liberated from the surface of lithium work function radiation 2 15 eV by electromagnetic whose electric component varies with time as E a 1 cos wt coswot where a is a constant w 12 1014 rads 1 and wo 3 6 10 5 rads 1 h 6 6 10 34 in Sl units

1 An objective lens consist of i Short aperture and short focal length ii Large aperture and large focal length iii Short aperture and large focal length iv Large aperture and short focal length

1 The string shown in the figure is passing over small smooth pulley rigidly attached to trolley A If speed of trolley is constant and equal to VA Speed and magnitude of acceleration of block B at the instant shown in figure is A VB VA ap 0 3 C VB 11 5 VA B a 0 D ag 16V A 125 A OTO BO x 3cm h 4cm

A plane mirror is placed at a distance d from the screen on which spot is formed Ray is kept constant and mirror is rotated with constant angular velocity Then the acceleration off the spot on the screen is given by m Plane mirror 0 3 screen

8 Why is it necessary to introduce a cylindrical soft iron core inside the coil of a galvanometer 7 9 0 77 i when the magnetic field is radial as in the case of cylindrical pole pieces and soft iron core then in every position of coil the plane of the coil is parallel to the magnetic field lines so the coil experiences a uniform torque on it as deflection torque NIAB c ii when the magnetic field is radial as in the case of cylindrical pole pieces and soft iron core then in every position of coil the plane of the coil is perpendicular to the magnetic field lines so the coil experiences a non uniform torque on it and SO deflection torque NIAB iii when the magnetic field is radial as in the case of cylindrical pole pieces and soft iron core then in every position of coil the plane of the coil is in axial line to the magnetic field lines so the coil experiences a maximum torque on it as deflection torque c NIAB iv None of the above

0103 a mass of A particle having a 5 10 C The particle is given a of 10 ms in the presence of electric field kg carries a charge of an initial horizontal velocity E and magnetic field B To keep the particle moving in a horizontal direction it is necessary that B should be perpendicular to the direction of velocity and E should be along the direction of Both B and E should be along the direction of 2 velocity 3 Both B and E are mutually perpendicular and perpendicular to the direction of velocity B should be along the direction of velocity and E should be perpendicular to the direction of 4 velocity Which one of the following pairs of statements is possible a 1 and 3 c 2 and 3 b 3 and 4 d 2 and 4 AIPMT Mains

21 If equivalent resistance between points A and X is 5 92 and equivalent resistance between A and B is 10 2 then find R A 100 B 1 222 2 59 3 39 X 4 100 sch www R R 2 V 2 V X 39 3 R R R 3 4 R R 10 R 95

For the circuit Figure 1 take 300 V R 4 0 kn R 6 0 kn and assume the capacitor is initially uncharged Figure R ww ww R 1 of 1

Positive rays travelling from west to east enter in a region of electric field directed vertically upwards The deflection of the rays is towards Neglect effect of gravity 1 Vertically upwards 2 Vertically downwards 3 North 4 South

A dielectric slab of thickness d 2 and dielectric constant 2 is inserted in capacitor as shown in figure If capacitor is connected to 10 V emf battery then find potential difference between the two surface A and 8 of dielectric slab 1 2 3 Otroct Answer 4 Our Answer 3 atus incorrect 4 V 20 3 5V 10 3 V D

When a thin convex and a thin concave lens are placed in closed contact their equivalent focal length is 50 cm The ratio of power of convex and concave lens is 2 1 then their individual focal lengths are 120 cm 40 cm 2 25 cm 50 cm 20 cm 40 cm 4 35 cm 45 cm

A long straight conductor carrying current I is fixed on a smooth plane A circular loop is placed on the same plane as shown in the figure If the current I through the wire is increasing then the loop will move towards 1 Right 2 Left 3 Up 4 Down O

amina is made by removing a small disc of diameter 2R from a bigger disc of uniform mass density and radius 2R as shown in the figure The moment of inertia of this lamina about axes passing through O and P is I and Ip respectively Both these axes are perpendicula Ip to the nearest integer is to the plane of the lamina The ratio Io 2R 0 2R P

x An infinitely long solid cylinder of radius R has a uniform volum spherical cavity of radius R 2 with its centre on the axis of the cylinder as shown in the figure The magnitude of the electric field at the point P which is at a distance 2R from the axis of the cylinder is given by the expression The value of k is 1 R 2 AZ R P 2R Y 23pR 16ko

Solution m Mass of system M m Force on system F Acceleration of system a F M m F Force on system Mass of system Vedanti JEE Lets first find acceleration of system To find acceleration take block and whole of rope as a system Solution To find tension at midpoint take block and half of rope as a system 3 Vedanti JEE 3TER midpoint of rope

If Q charge is distributed inside the material of a shell of inner and outer radii R and then non conducting R respectively Q P 1 Electric field inside shell must be zero 2 Electric field inside shell may be zero 3 Electric field inside shell is constant and non zero 4 Electric field inside shell is zero if Q is positive and non zero if Q is negative

27 similar drops of mercury are maintained at 10V each All these spheric drops combine into a single big drop The potential energy of the bigger drop is times that of a smaller drop Answer

A conducting rod of length L rotating in x z plane with constant angular velocity about an axis yy in an uniform magnetic field B as shown in the figure The emf Induced between the ends P and Q at the instant shown will be y 3x B B k X 3 X L 4 1 Zero BL 2 X 34x 4 X 2 4 Q X BL 0 4 10 X BL

34 An electron and a proton are held 2 m apart The midpoint between the electron and the proton sets the origin of a co ordinate system with the x axis pointing toward the proton a A second electron is moved to the origin from infinity How much work does this take b Keeping the second elec tron fixed at the origin a third electron is sent toward the ori gin with a velocity of 400 m s from the location 0 m 10 m How close does this electron get to the origin

distance from a long line charge linear charge density 2 as shown in the figure The value of electric force experienced by dipole varies with distance ras 1 4 2 1 211Eor

One of the circuits for the measurement of resistance by potentiometer is shown The galvanometer is connected at point A and zero deflection is observed at length PJ 30 cm In second case the secondary cell is changed Take Es 10 V and r 10 in 1st reading and Es 5V and r 20 in 2nd reading In second case the zero deflection is observed at length PJ 10 cm What is the resistance R in ohm Ep P R wwww www J A

1 As shown in the figure below the particle of mass m and charge q will touch the infinitely large plate of uniform charge density o if its velocity v is more than Given that oq 0 0 load 6 q m d 2 20qd m o bunu J

Two long line charges of linear charge densities and A respectively are fixed r distance apart as shown Electrostatic force per unit length on it is equal to 1 H 41 0 2 1 2 2 r 1 X X 2 4 K 2 1 2 2 2 2 2 1 2 22

0 0 0 200 tls 400 600 ci Hot water from a reservoir maintained at constant temperature is being added at a very slow and constant rate in a calorimeter initially containing 1 0 kg of water at temperature 20 C The water in the calorimeter is being continuously stirred to maintain its temperature uniform The graph shows how the temperature of water in calorimeter changes with time t Assuming heat loss to the surroundings and work done in the stirring process to be negligibly small find the temperature of the hot water reservoir 80

charge densities at point P and Q are op and o respectively If 10 C charge is moved from centre C to point S then S 211 C 1 op will increase and will decrease 2 op will decrease and will decrease 3 op will increase and oo will remains unchanged 111 7 unchanged

1 36 Two steel balls fall freely on an elastic slab The first ball is dropped from a height h and the second from a height h h h T sec after the first ball After the passage of time T the velocities of the balls coincide in magnitude and direction Determine the time I and the time interval during which the velocities of the two balls will be equal assuming that the balls do not collide

1 A voltage e t 100sin314t is applied to a series circuit consisting of 10 resista 0 0318H inductance and a capacitance of 66 3 F Determine i Expression for i t ii Phase angle between voltage and current iii Power factor iv Active power consumed Also draw the phasor diagram

Two identical balls having like charges and placed at a certain distance apart repel each other with a certain force They are brought in contact and then moved apart to a distance equal to half their initial separation The force of repulsion between them increase 4 5 times in comparison with the intital value The ratio of the final charges of the balls is Question Type Single Correct Type 12

41 There is a set of 4 tuning forks one with lowes frequency vibrating at 552 Hz By using any two forks at a time the beat frequencies heard are 1 2 3 5 7 8 The possible frequencies of othe three forks are 1 553 554 and 560 Hz 2 553 555 and 560 Hz 3 553 556 and 558 Hz 4 551 554 and 560 Hz

Two co axial rings of same radius R 10 cm are placed parallel to the y z plane such that x axis is the axis of the rings Ring 1 carries a current of 2 Ampere and ring 2 carries a current of 1 Ampere as shown in the figure The separation between the rings is d 50 cm Find the magnitude of B dx where B 440 is the net magnetic field at any point on the axis Current in both the rings are in opposite sense Ring 1 Ring 2 Oro

A block of mass M 1 6 kg is lying on a plane incline at an angle of 0 37 to the horizontal The coefficient is 0 2 At the same time the block on the incline plane is released a shell of mass m 0 4 kg is fired into it horizontally with a speed of v 12m s and gets embedded How much will the block and the shell slide up the incline A 0 15 m C 0 10 m B 0 20 m D None of these M 0 3

A motorboat can maintain a constant speed of 22 miles per hour relative to the water The boat makes a trip upstream to a certain point in 27 minutes the return trip takes 17 minutes What is the speed of the current The speed of the current is mile s per hour

Solution Take the block as the system The force on it are the figure Find the tension in the string a point i B lower end ii A mid point a Pull of the string T upward b Pull of the earth Mg downward T Ma 0 T Mg T A B M E M

19 A particle is executing SHM according to equation 4 its displacement at t 2 s is 20 y 10 cos 2rt 10 2 2 m 1 5 2 m 3 5 m 4 Both 1 2 Five moles of hydrogen gas are heated from 30 C

a A disk of radius 4 having a uniformly distributed charge 6 C is placed in the X Y plane with its centre at a 2 a 5a 0 0 A rod of length a carrying a uniformly distributed charge 8 C is placed on the x axis from x 4 to x 4 3a 3a respectively Consider a cubical Two point charges 7 C and 3 C are placed at 4 4 surface formed by six surface x a a a 2 y 2 z 2 The electric flux through this cubical surface is a a 1 7 0 and Question Type Single Correct Type 1 2C 0

A ball is released on a smooth plane A of constant length as shown After that it moves smoothly to another smooth incline of inclination 60 Find the angle of plane A with vertical in degrees so that the ball reaches the incline in the shortest time A g 4