Physics Questions

ang s double slit experiment is performed in air central maxima is obtained on screen at some position Two slabs are placed in front of two slits S and S The slab placed in ckness t and of refractive index 1 6 and the slab placed in front of S is of refractive index 1 4 Find its thickness if position of central maxima remain unchanged on putting two s 1 51 1 41 1 61 8t

45 A charge particle of charge q and mass m enters in a given magnetic field B and perpendicular to the magnetic field as shown in the figure It enters al an angle of 60 with the boundary surface of magnetic field and comes out at an angle of 30 with the boundary surface of the magnetic field as shown in the figure Find width d in which magnetic field exist a c 3 1 mv 4qB 3 1 mv 3aB xx x x 60 x X X B XX XX x x d X x X 30 X b X X d 3 1 mv qB 3 1 mv 0 2qB

Catalyst 85 Two particles of equal mass m are connected by a spring of spring constant K kept on a smooth floor Each of the bodies are given equal speed vir the opposite direction Calculate the maximum compression of the spring 1 2 3 2 V 2m k LEL E bas tothod ritroms nainge en hold issiinsbi ONT La novip 21 8

itor is charged to a potential of 5 V and then connected to position 1 with the shown polarity for 1s After 1s it is connected across the inductor at position 2 C 5 10 1 3 v x V e 10092 www E 10V I O 112 The potential across capacitor after 1s of its connection A 5 x 103 2 V B e 10mF D L 2 5 mH to position 1 is 100 21 e 5 x 103 None of these V

in ncert in page 379 chapter waves and in page 389 sum ry boundary condition equation of reflected wave are gi en differnt which is correct equation with or equatic with u or an integral multiple of 2 x the waves are exactly in pha is constructive if o z they are exactly out of phase and the inte A travelling wave at a rigid boundary or a closed end is reflecte but the reflection at an open boundary takes place without ar For an incident wave y x t a sin kx ot the reflected wave at a rigid boundary is y x a sin kxot For reflection at an open boundary y x t a sin kx 000 The interference of two identical waves moving in opposite dire waves For a string with fixed ends the standing wave is gi se change on vs of reflection at an open boundary To put this mathematically let the incident travelling wave ng a the in of has it it ton by the all be x t a sin kx ot At a rigid boundary the reflected wave is given y x t a sin kx ot n a sin kx wt 15 35 of At an open boundary the reflected wave is given ed by at nowr in fa am ele an ph el vi di IT a

4 X 2 2 A student measures the distance traversed in 8 free fall of a body initially at rest in a given time He uses this data to estimate g the acceleration due to gravity If the maximum percentage errors in measurement of the distance and the time are e and e respectively the percentage error in the estimation of g is 1 e 2e 2 e e 3 e 20 4 e e A particle starts from origin moves towards 9 x y afte C yfe 1 c 2e 3 e 2c C fanfarenaff a ta at an ad fa fa f 2 e 0 4 c 0 z ph

34 Two sound waves move in the same direction If the average power transmitted across a cross section by them are equal while their wavelengths are in the ratio of 1 2 Their pressure amplitudes would be in the ratio of a 1 c 4 b 2 d

The temperature difference between the hot and cold end of a thermally conducted body is increased from 10 C to 20 C then thermal conductivity of body b becomes double d becomes four times at the end of the next 10 minutes 000 in 19 minutes If the room temperature is 25 C and assuming a remains constant c becomes half

3 A small ball is projected from point P on floor towards a wall as shown It hits the wall when its velocity is horizontal Ball reaches point P after one bounce on the floor If the coefficient of restitution is the same for the two collisions find its value SRAMA P YATHE

In radioactive decay process the negatively charged emitted B particles are The electrons orbiting around the nucleus The electrons produced as a result of collision between atoms The electron present inside the nucleus The electrons produced a result of the decay of neutrons inside the nucleus

d None of the above In a deflection magnetometer the needle is short and the pointer is long because the a needle cannot be made long b circular scale cannot be made short c needle must be in a uniform field pointer must be in a non uniform field in tan A a

A small bar magnet P is moving with a constant velocity v towards a fixed conducting ring of radius a along its axis as shown in the figure Electrical resistance of the ring is R and its self inductance is vanishingly small The bar magnet can be modelled as magnetic dipole P of dipole moment m Find force of interaction between the bar magnet and the ring Ans 9M a4m x Repulsive 4810 x 15

101 A light ray takes t time to travel a distance x in air The same light ray takes 8t time to travel 3x distance in a medium then the critical angle when the light ray is passing from the medium to air is 1 45 2 60 3 sin 8 1 4 sin 3

The materials suitable for making electromagnets sho have a high retentivity and high coercivity b low retentivity and low coercivity c high retentivity and low coercivity d low retentivity and high coercivity

zero dip c zero declination d equal declination mig lasinsv nols onil Two magnets have the same length and the same pole strength But one of the magnets has a small hole at its tomonsvleg nogosts 6 centre Then vom a both have equal magnetic moment b one with hole has smaller magnetic moment c one with hole has larger magnetic moment d one with hole loses magnetism through the hole

53 In an astronomical telescope in normal adjustment a straight black line of length L is drawn on inside part of objective lens The eye piece forms a real image of this line The length of this image is 1 The magnification of the telescope is a I 0 1 b 1 I d L 1 1 1 AIPMT Re 151

19 Compute the additional velocity required by a sa orbiting around earth with radius 2R to become from earth s gravitational field Mass of earth is M 2 1 a c 2GM 2 1 VR GM 3 1 VR b d GM 2R GM R 2 1 27 As W es 2M m and M are respectively

Answer should be third Energy required to move an Earth s satellite of mass m from an orbit of radius R to 5R is M mass of earth R radius of earth GMm 5R 2GMm 3R

Figure shows the initial velocity and acceleration of a body The direction and absolute value of the acceleration remain constant Find the time and radius of curvature when the velocity reaches its minimum value Remin Vo cos a v sin a

permeability versus magnetic intensity H has the following shape PrA a c Hra H H teria b d Hr A Mr A H H

A ball thrown upward from the top of tower with speed v reaches the ground t1 second If this ball is thrown downw ard from the top of the same tower with speed v it reache s the ground in t2 second In what time the ball shall reac h the ground if it is allowed to fall freely under gravity fro m the top of the tower A t t 2 B t t 2 C t t D t t

35 The fundamental frequency of a sonometer wire of length lis fo A bridge is now introduced at a distance of Al from the centre of the wire Al 1 The number of beats heard if both sides of the bridges are set into vibration in their fundamental modes are 8f04 1 2f04 a c b d foAl 1 4f0Al

A metal ball of radius a is surrounded by a conducting medium extended upto infinity The resistivity of the medium varies as p pr where r is the distance from the centre of the sphere The electrical resistance of the medium above the metal surface up to r 2 a is

2 A bob is suspended by means of a light string of length from a rigid support When the bob is in equilibrium it is given a horizontal velocity of 2ge then 1 it moves in vertical circle 2 it oscillates 3 tension is not zero at any point 4 velocity is not zero at any point

large cruise ship of mass 6 60 x 107 kg has a speed of 10 4 m s at some instant a What is the ship s kinetic energy at this time 3570000000 b How much work is required to stop it Give the work done on the ship Include the sign of the value in your ans 3570000000 J c What is the magnitude of the constant force required to stop it as it undergoes a displacement of 2 40 km 1370000 Your response is within 10 of the correct value This may be due to roundoff error or you could have a mistake in

A solenoid 1 0m long and 0 04 m diameter has 700 turns Another solenoid of 50 turns is tightly wound over the first solenoid Then the emf induced in the second solenoid when the current in the first solenoid changes from 0 to 5 A in 0 01 s Take f 10 is nx10 volts Find n ignore edge effects

ilance shift hould 1 122 it circuit th cell mf emf 2 iternal oint of hen a circuit nifts to The 131 Current Electricity 20 Pick out wrong statement about the Kirchhoff s laws of electric circuit NCERT Pg 116 1 Outgoing currents adds up and are equal to incoming currents at a junction 2 Electric potential in electric circuit is position dependent Starting with any point if we come back to same point total potential change must be zero 3 Junction rule is based on conservation of energy law Bending or reorienting the wire does not the validity of Kirchhoff s 4 nge

17 The block is placed on a frictionless surface Ill gravity free space A heavy string of a mass m is connected and force Fis applied on the string then the tension at the middle of rope is M 1 5 M F 2 m M 3 zem ZZZZZZF M 2 2 m m M m F M F

A small flat search coil of area 4 cm with 20 closely wound turns is positioned normal to the field direction and then quickly snatched out of the field region The total charge that flows in the coil is 7 5 mC The resistance of the coil and galvanometer is 0 8 2 If the field strength of the magnet is Nx102T find the value of N

c 2 If a magnet is hanged with its magnetic axis then it stops in a magnetic meridian c angle of dip anet of magnetic b geometric meridian d None of these moment 2 J T is aligned in the the net wor 71

A stone projected at an angle of 60 from the ground level strikes at an angle of 30 on the speed of projection of the stone in m s Take the roof of a building of height h Find h 30m g 10 m s 30 SRAM VEVA 60 h YATHE

Sir answer given is 2 into 10 to the power 2 I am not getting its answer please explain in detail

Figure shows wave fronts coming form a source at equal interval of 10 3 milli second Frequency of wave emitted by source is 300 Hz XX is line along common diameter wave fronts passing through A Distance between two consecutive wave fronts along line XX is 0 9 m and 1 3 m in the right and left of point A respectively At some insta source is at point A Detector is placed at point Q AQ makes an angle 60 with lin XX If frequency of wave received by detector is f Hz then VA SRAM 650 110 in Hz is equal to ATHE

Width of a river is 60m A saimmer wants to cross the river such that he reaches from A to B directly Point 8 is 45m ahead of line AC perpendicular to river Assume speed of river and speed of swimmer as equal Swimmer must try to swim at angle with line AC Value of 6 is

3 5a 2 4 5a y A particle of masss m is suspended by a spring if 7 frequency of its oscilation is n cm k here c is a dimensionless constant then the value of x and y are 1 X 2 x x X 1 y A student measures the distance traversed in 8 3 5a 2 faxi far m 304 f 33 cm k cf X 2 x X 4 5a X fanfaren eff

Two blocks are placed at rest on a smooth fixed inclined plane A force Facts on block of mass m and is parallel to the inclined plane as shown in figure Both blocks move up the incline Then F 0 m i Draw free body diagram of block of mass m and block mass m i Find accelerations of block of mass m and block mass

no For a simple harmonic oscillator of mass 10 kg and amplitude A 2m the variation of potential energy U as a function of displacement x from mean position is as shown The time period of oscillation in seconds is 1 A KIN 3 12 2m 30 J TO J 2 2 X

For a rigid body we know that if various forces at various points in it the resultant motion is as translation and a net torque at the CM causing net force acts on the CM centre of mass causing earth sun system approximating the earth as a rotation around an axis through the CM For the INCERT Exem uniform density sphere the torque is zero b the torque causes the earth to spin c the rigid body result is not applicable since the e not even approximately a rigid body 1 the torque causes the earth to move

A man can swim with a velocity v relative to water He has to cross a river of width d flowing with a velocity u u v The distance through which he is carried downstream by the river is x Which of the following statements are correct du A If he crosses the river in minimum time x V du B x cannot be less than V T C For x to be minimum he has to swim in a direction making an angle of 2 the direction of the flow of water T D x will be maximum if he swims in a direction making an angle of 2 sin u with with the

A stone is thrown vertically upwards with a velocity of 19 6 m s After 2 second another stone is thrown upwards with a velocity of 9 8 m s When and where will these stones collide take g 9 8 m s

A particle is projected from point A that is at a distance 4R from the centre of the earth with speed v in a direction making 30 with the line joining the centre of the earth and point A as shown The particle passes grazing the surface of the earth Consider gravitational interaction only between these two Find v in km sec GM use 6 4x107m s R THE NAR 4R D R A GROUP

As shown in the figure P and Q are two coaxial 32 fa fa fennta conducting loops separated by some distance When the switch S is closed a clockwise current Ip flows in P as seen by E and an induced current Io flows in Q The switch remains closed for a long time When S is opened a current lo flows in Q Then the directions of Io and IQ as seen by E are Ro 1 Respectively clockwise and anticlockwise 2 Both clockwise 3 Both anticlockwise 4 Respectively anticlockwise and clockwise a fer fr femnat un 1 varfra aft E M Qka u Lo varfra stazi faa and Gr 444 dss and was a feat sa ar a Q10 1o 1o sfera feat o 1 va ama 2 ali afever 3 4 3421 va aferunad

ed green and violet light are falling on the refracting face of a prism all at the same angle of incidence If their angles of deviation are 8 82 and 83 respectively then 9 A

114 A body is projected vertically up from ground After 2 seconds it is at a point P and further in took 4 seconds from P to reach ground Them height of point P above ground is g 10 m s 1 10 m 3 30 m 2 20 m 4 40 m

32 The radii of circular orbits of two satellites A and B of the earth are 4R and R respectively If the speed of satellite A is 3 V the the speed of satellite B will be a 3V 4 c 12 V Lo b 6 V d 3V 2 CBSE Pre 2010

Three long wires carrying current 10 A 20 A and 30 A are placed parallel to each other as shown Point P and Q are in midway of wires What is ratio of magnetic field at P to the Q 30 A 1 02 1 03 2 02 3 2d 20 A 2d P 10 A

5 Which of the following sentences are correct 2 Points To observe the interference due to thin film is illuminated by extended source thickness of the film should be much much smaller than coherence length of source optical path difference between superposing waves must be much

A battery of emf V volt resistance R and R a capacitance C and switches S and S are connected in an electrical circuit as shown in figure The capacitor C gets fully charged to V volt when T R S C ww R S A S and S are both closed B S and S are both open C S closed and S open D S closed and S open

e charge Q in order to make the net force on q to be zero PTIONS A 9 Solution Let the distance between the charges 4g and q be 1 4q x 0 kQq 3 Q F 1 2 x 1 2 For q to be in equilibrium fact 0 Q and q must be oppositely charged Let Fi and F is the force experienced by q due to charges Q and 4q respectively Thus Fi F k 4q q 12 q X 1 F F is the attractive force by Q and F is repulsive force by 4g 4kQq 4kq 2 Q 9 Since Q and q are of opposite nature Q 9

The small current in reverse bias condition are due to A B D Electrons Majority charge carriers i e electrons on n side and holes on p side Minority charge carriers i e electrons on p side and holes on n side Temperature