Physics Questions

Total internal reflection can take place only if Select an answer A B C D light goes from optically rarer medium to optically denser medium 21 light goes from optically denser medium to rarer medium C the refractive indices of the two media are close to each other the refractive indices of the two media are widely different

x axis between reflecting walls at x 0 and x a Between these two limits it moves freely at constant velocity v If the walls are perfectly reflecting then its displacement time graph is A B C D displacement displacement displacement Hisplacement 0 0 a v 2a v 3a v time a v 2a v 3a v time time

8 A closed organ pipe and an open pipe of the same length produce 4 beats when they are set into vibrations simultaneously If the length of each of them were twice their initial lengths the number of beats produced will be 1 2 2 4 3 1 4 8 frequer under increas the occ wires w 1 0 01

a C in south west direction The displacement of the person from the origin will be 10 m along north 10 m along west b d 10 m long south Zero W N

The impulse imported by an electromagnetic pulse of energy 1 5 10 2 joule when it falls normally on a perfectly reflecting surface is Onig one correct answer A B 4 x 10 10 kg mo s 2 10 10 kg m s C 10 10 kg m s

A 5 0 dioptre lens forms virtual image which is four times the object placed perpendicularly on the principal axis of the lens The distance of the object from the lens is found to be 10 X cm Determine X Write an answer

A point source of light at the surface of a sphere causes a parallel beam of light to emerge from the opposite surface of the sphere The refractive index of the material of the sphere is Considering sin 0 Write an answer

A block of mass m is pulled by a force of constant power P placed on a rough horizontal plane The friction coefficient between the block and the surface is Then P The maximum velocity of the block during the motion is mg B The maximum velocity of the block during the motion is P 2 mg C The block s speed is never decreasing and finally becomes constant D The speed of the block first increases to a maximum value and then decreases

Block A B C connected with light string with larger block M as shown in figure Pullies are light and frictionless There is no friction anywhere Which is the correct FB D of larger block of mass M A C T T2 T T N Mg T AN T De Mg T1 B T2 T2 N Mg D None of these T1 m B in bas M Smooth surface

ng a Is it possible for the mot straight line so that its velocity increases while its acceleration decreases 1 No because if acceleration is decreasing the object will be slowing down 2 No because velocity and acceleration must always be in the same direction Yes an example would be a falling object near the surface of the moon 4 Yes an example would be a falling object in 3

D A film of refractive index n and thickness t is deposited on a substrate of refractive index p such that p n Light of wavelength l is falling normally on film Condition for maxima in reflected light is given by Point 2nt ml where m 0 1 2 2nt 2m 1 1 2 where m 0 1 2 None of these

Problem Consider a two dimensional square lattice with one atom of mass m per lattice point interacting with 4k qa only nearest neighbours with force constant k Take the phonon dispersion curve to be m sin 2 At high temperature kT ho the mean square displacement of an atom from its equilibrium position will be a kT k b 2KT c 4k 2kT d 4

The half life of a radioactive substance is 20 minutes The approximate time interval 1 1 between the time t when 2 3 of it has decayed and time t when 1 3 of it has decayed is a 7 min c 20 min b 14 min d 28 min

9 UN PL Two charges q and q are plac apart as shown in the figure below B shame Po nhentung Syn Pathol yn Coating na trzissu I Jusb 2 q ME JCB JF Ut A along vector A C along yontou 2009 q noringnib brandsda The electric field at a point P on the perpendicular bisector as shown as B along vector B

16 Two identical holes each of cross sectional area A are opened on the opposite sides of a wide vertical vessel filled with water The difference in vertical height of the two holes is h The resultant force of reaction of wa ter flowing out of vessel is A hpgA C 2hpgA B hpgA D hpgA 4

13 Which of the following sentence is correct 1 Point O O Condition of constructive and destructive interference for transmitted and reflected light from a thin film are same Condition of constructive and destructive interference for transmitted and reflected light from a thin film are complementary

b The molecules of a gas have two states of internal energy with statistical weights gi g2 and energies 0 respectively Calculate the contribution of these states to the specific heat of the gas 4 c Two states with energy difference 4 83 x 10 21 joule occur with relative probability e Calculate the temperature Given k 1 38 10 23 J K 3

A symmetric double convex lens is cut in two equal parts by a plane perpendicular to the principal axis If the power of the original lens was 4 D the power of a cut lens will be Select an answer A 2D B C D 3 D 4 D 5 D

Two identical photo cathodes receive light of frequencies f1 and f2 If the velocities of the photo electrons of mass m coming out are respectively v and v then A V1 V2 D v v 2h 2h B V V f1 f2 m 2h f f m m 1 2 2h C V V2 m 1 2 f f

Work function of two metal surfaces are 2 0 eV and 3 0 eV Both are illuminated by light energy of incident photons greater than 3 eU If graph is plotted between maximum kinetic energy and frequency for both surfaces then slope of the graphs are in the ratio Only one correct answer 9 2 3 B 3 2 C 7 1

of sphere Cis A are three identical smooth sphere placed on frictionless inclined plane as shown in figure then F B D 4 N 60 mg B N 90 D mg 00 IN C NN 60 mg D N 60 mg N

Two cells of the same e m f e but different internal resistances r and r are connected in series with an external resistance R The potential drop across the first cell is found to be zero The external resistance R is A 1 1 C 2 B 1 12 D r 1 FF 6 r www R

The velocity field in a two dimensional unsteady flow is given by v x y t 2xy 3xyj m s The magnitude of acceleration of fluid particle located at x 1 m y 1 m at the time t 1 s in m s is

1 A point object is placed at a distance of 30 cm from a convex mirror of focal length 30 cm The image will form at A infinity B pole C focus R 15 cm behind the mirror

A plane travelling at 256 m s uses ultrasoni c sound generator that generates a wave of wavelength 1 6 cm and frequency 22 kHz to measure the altitude It receives the reflecte d signal 8 seconds later Find the altitude

If one were to apply Bohr model to a particle of mass m and charge q moving in a plane under the influence of a magnetic field B the energy of the charged particle in the nth level will be a n hqB 2 m c hqB 8 m hqB b 4km hqB d 3 TM

The energy flux of the light emitted by a source of light is 50 Wm 2 This light energy falls on a plate of area 5 cm which completely absorbs this energy Find the force exerted on the plate if the plate is exposed to light for 10 minutes If the plate is replaced by another plate of same area but which completely reflects the light falling on it Find the force exerted on the plate in this case 0 11 16 6 X 10 11

A large block of mass M on a smooth inclined plane is connected via a string to a small block m which is attached to a relaxed spring of force constant k with its other end attached to the ground see diagram Which of the following forces do NEGATIVE work as the large block slides down the incline A The tension force on m C The spring force on m M celllle B The gravitational force on m D The tension force on M

3 A particle having charge q and mass m is projected from the origin with velocity vo in a uniform P k magnetic field B Bok at time t 0 If x t y t z t represent x y and z co ordinates of the particle at time t then select the correct option s 1 y t mv qB 2 x t 3 y t mvo qB mvo qB 4 z t vot 1 cos COS qBt m 1 sin qB m qBt m

5 A rectangular loop carrying current i is shown in the diagram If the magnetic field in the region is 2B1 Bo then choose the correct statement s av a G X VZ 1 Magnetic moment of the loop is ali 2 Magnetic moment of the loop is ali i 1 3 Torque on the loop is aliB k 4 Torque on the loop is K

Two blocks of mass m and 2 m are connected with a string which is passing over a pulley disc of mass m and radius R as shown in the figure If system is released from rest then acceleration of the block will be T m R T

7 i Calculate Einstein s frequency for copper for which 0230 K Given h 6 6 10 34 J sec Boltzmann constant k 1 37 x 10 23 Joule K E ii Use result i to show that the classical result C 3R should be valid for copper if T 230 K i Finstein s frequency s bu

If current I flows through a closed loop as shown then the magnetic field at the centre O is Only one correct answer R 20 6 0 sin 0 440 I 2x R B C PO I 2 R 0 sin 0 I C 2m 0 sine po 1 T A tan A

Water is flowing through a channel that is 12 m wide with a speed of 0 75 m s The water then flows into four identical channels that have a width of 4 0 m each The depth of the water does not change as it flows into the four channels What is the speed of the water in one of the smaller channels Question Type Single Correct Type 1 0 56 m s 2 2 3 m s Totul NUL 3 0 25 m s

2 What is the effect on null deflection of galvanometer when the radius of 1 point the wire is tripled a No change Ob Becomes half c Reduces by 1 3 Od Thrice the original value

Two blocks A and B of mass m and 2m are connected by a massless spring of force con stant k They are placed on a smooth hori zontal plane Spring is stretched by an amount x and then released The relative velocity of the blocks when the spring comes to its natural length is ADRURORS A C 3k 2m 2kx m X B D B 2k 3m 3km V 2x X

A body moving with uniform retardation covers 1 5 km before its speed reduced to half of its initial value It comes to rest in another 11 m 11 7 m 11 2 m 1 km 11 5m 2 km A particle starts with an initial velocity 3 m s along the positive X axis and it accelerates uniformly at the rate of 0 60 m s The distance moved by it in first three seconds is 3 km 1 1 12 km 3 1 A car moving with a velocity of 80 km hr is slowed down to 44 km hr in 15 s The retardation is 4 0 67 m s 1 m s 1 25 m s 1 5 m s reach a velocity of 9 m s of 0 60 m s How much is the time taken by it to positive x axis and it accelerates uniformly at the rate A particle starts with an initial velocity 3 m s along the 2 A car moving at 72 km hr is stopped by applying breaks with a distance of 50 m The retardation experienced by car is 5 4 m s 2 m s 3 m s O 1 m s

16 An electric current of 16 A exists in a metal wire of cross section 106 m and length 1 m Assuming one free electron per atom The drift speed of the free electrons in the wire will be Density of metal 5 x 10 kg m atomic weight 60 A 5 x 10 m s B 2 x 10 m s D 7 5 x 10 3 m s C 4 x 10 m s

9 A projectile is thrown with a velocity of 20 m s at an angle of 600 with the horizontal After how much time the velocity vector will make an angle of 450 with the horizontal in upward direction is take g 10m s A 3 sec B 1 3 sec C 3 1 sec D None of these

1 25 pts As shown in the figure two particles carrying opposite charges 91 0 and 9 0 are a small distance apart from each other separated by the flat face of an insulating hemisphere of radius R The hemisphere contains only the positive charge 9 so that it is located just below the center of the flat face The charge 42 is located just above the center of the flat face What is the electric flux a through the curved surface and b through the flat face as 8 0 092 q1 R

8 In the circuit shown in figure K is open The 18 charge on capacitor Cin steady state is q Now key is closed and at steady state the charge on C 141 is q The ratio of charges ww THE 2 K alm 12 4 19 2R In the given circuit calculate the potential 19 Aku gaf K yeft bi fra starten cunfer START q1 af e 32 3 1 C STTIT q1 92 www R 92 2 K 2R 4 f after eft een 2 F instaford 73

7 Two small balls each having equal po charge Q are suspended by two insulating strings at equal length L metre from a hook fixed to a stand The whole set up is taken in a satellite into space where there is no gravity Then the angle 0 between two strings and tension in each string is 1 0 3 kq 1 2 kq L Q Stand L Q 2 kq 21 kq 2

In the figure below a ball of mass 5 kg starts at point A with a speed of 15 m s on a flat frictionless surface After point B it trav els on an incline BC with coefficient of kinetic friction 0 15 At point B the ball smoothly changes the direction The length of the incline is 2 2 m and it makes an angle of 15 with the horizontal What is the work done by friction What is the velocity of the ball at point C Given Sin 15 0 25 Cos 15 0 95 A B 8

A spectrometer gives the following reading when used to measure the angle of a prism A Main scale reading 58 5 degree Vernier scale reading 09 divisions Given that 1 division on main scale corresponds to 0 5 degree Total divisions on the vernier scale is 30 and match with 29 divisions of the main scale The angle of the prism from the above data a 58 59 Degree c 58 65 Degree AIEEE 2012 b 58 77 Degree d 59 Degree

In Young s double slit experiment one of the slit is wider than other so that the amplitude of the light from one slit is double of that from other slit If I be the maximum intensity the resultant intensity when they interfere at phase differ ence is given by I a 1 20 2 m1 2 cos 3 1 8 cos 9 2 1 b b d m1 4cos 5 4 5 cos

05 Six charges are placed at the corner of a regular hexagon as shown If an electron is placed at its centre O force on it will be Ar 79 3q 29 F 2g E B A zero C along OC 29 29 D C B along OF D none of these

Three identical voltmeters A B and Care connected as shown in a circuit If the readings of voltmeters A and B are 7 5 V and 5 V respectively then find the reading of voltmeter Cin volts wwww 902 14 52 A B O

5 A circuit has a section ABC as shown in figure If the potentials at point A B and C are V V2 and V3 respectively The potential at point O is A V V V C Zero B VV V R R R R R R V V D X X X R R R R R R

A long solenoid of radius R has n turns per unit length It is fed by an alternating current I I cos wt where I is the peak value and w is the angular frequency The peak value of the induced emf in a concentric circular ring of radius r R is given by A B 3 nl wR 2r 3 nl wR r C nI R D Tunior 2

A power supply of fixed emf E is connected to a variable resistor resistance R and an ammeter of resistance RA The internal resistance of the supply is r The potential difference between the terminals of the power supply in closed circuit is denoted by V and the current in the circuit is denoted by I A graph is obtained between V and I by drawing varying amount of current from the supply The correct V I graph for the given situation is TO 2008