Basic Physics Questions and Answers

1 has no written records b Modern Prehistory 2 Pottery and jewellery are a tools 2 b paintings 3 The Indus Valley Civilization is a part of b medieval a ancient b Indus 4 The Indus Valley Civilization flourished on the banks of the river a Nile c Hwang Ho 5 The site of Kalibangan is in a Gujarat b Rajasthan c History mus c artefacts India c modern c West Bengal Write T for true and F for false 1 There are many written records of the prehistoric period 2 Indian history is divided into three periods 3 The Indus Valley Civilization was a part of medieval India 4 The people of Indus Valley made terracotta figures

Velocity v versus time t graph of a particle moving tan a tan then average speed of the particle till the time its velocity becomes zero is v m s in a straight line is shown in the figure If 4 B t s 2

The resistance of platinum wire at 0 C is 22 05 and at 100 C it becomes 22 70 When the wire is heated to a temperature of t C the resistance of wire becomes 24 912 The value of t is 1 220 2 440 3 310 4 550 1 2 3 4

Z 13 46 In the Boolean algebra AB A equals to 1 A B 2 A 3 B 4 A B Z 13 4 A 2 13 PCP Sikar 204 Propulsive PTS to 8 b WIT JEE 2 13 A 2 25 2 13 3 46 from t 2 A 3 A B

17 AB is a potentiometer wire of length 100 cm and resistance 10 ohms It is connected in series with a resistance R 40 ohms and a battery of e m f 2 V and negligible internal resistance If a source of unknown e m f E is balanced by 40 cm length of the potentiometer wire the value of E is 1 0 8 V A R wwwwww 12V 40 cm E 1 B 2 1 6 V

A uniform semicircular disc of mass M anc radius R hinged at point O a shown in figure is released from rest from a vertical position as shown If the initial magnitude of angular than the xg 3 TR value of x is Center of mass is at a distance 4R from center of disc 3 acceleration of the disc is R

Two blocks of mass 1 kg and 2 kg respectively are connected by a spring and kept on a frictionless table The blocks are pulled apart so that the spring is stretched and released from rest At a certain instant of time the block of mass 1 kg is found to be moving at a speed 2 m s What must be the speed of the other block at this instant O 1 m s O O 0 5 m s 4 m s 0 25 m s

Two identical non conducting solid spheres of same mass and charge are suspended in air from a common point by two non conducting massless strings of same length At equilibrium the angle between the strings is a The spheres are now immersed in a dielectric liquid of density 800 kg m and dielectric constant 21 If the angle between the strings remains the same after the immersion then A C electric force between the spheres remains unchanged electric force between the spheres reduces mass density of the spheres is 840kgm the tension in the strings holding the spheres YOU MARKED X YOU MARKED

23 A Ferris wheel is elevated 1 m above the ground When a car reaches he highest point on the Ferris wheel its altitude from ground level is 31 m How far away from the center horizontally is the car when it is at an altitude 24 m

4 A person walks the following distances in the sequence given 1 500 meters north of west 2 1200 meters 0 east of north 3 1000 meters in east direction 4 500 meters south of east 5 1200 meters 0 west of south What is his net displacement

21 Apparent observer frequency frequency of train A is heard by in train B as 3 4 of the true Find the value of velocity of train B in m sec taking train A to be stationary If the sound velocity is 332 m sec A 110 C 75 B 108 D 83

7 A ball is thrown vertically downwards with velocity 2gh from a height h After colliding with the ground it just reaches the starting point Coefficient of restitution is B 1 2 A 1 2 C 1 D 2

N moles of a monatomic gas is carried round the reversible rectangular cycle ABCDA as shown in the diagram The temperature at A is T The thermodynamic 1 15 3 20 2P p P A B To D V 2V efficiency of the cycle is 2 50 74

A body sliding down in a inclined plane have coefficient of friction 0 5 If the normal reaction is twice that of resultant downward force along incline The angle between the inclined plane and the horizontal is 1 45 3 30 2 60 4 37

A heavy rope is suspended from rigid support A wave pulse is set up at the lower end Then O The pulse travels with uniform speed O The pulse will travel with increasing spee The pulse will travel with decreasing speed The pulse cannot travel through rope

unit cell is 400 pm long If 48 edge of a atomic weight of the element is 120 and it s density is 6 25 g cm The crystal lattice is use N 6 x 102 1 Primitive 2 Body centered 3 Face centered 4 End centered et ses enfant 400 pm 20 an 6 25 g cm 1 f N 6 102 1 2 3 4 f fe fa

122 A parallel beam of light travelling in water refractive index 4 3 is refracted by a spherical air bubble of radius 2cm situated in water Assuming the light rays to be paraxial the position of the image due to refraction at the first surface is A 6cm from the first surface B 12 cm from the first surface C 3cm from the first surface D 10 cm from the first surface

The focal length of a concave mirror is 30 cm Find the position of the object in front of the mirror on axis so that the image is three times the size of the object 40 cm 20 cm 50 cm Both 20 cm and 40 cm are possible

4 A drunkard walking in a narrowlane takes 5 steps forward and 3 steps backward each step of 1 m long per second and so on Determine how long the drunkard takes to fall in a pit 15 m away from the start

7 Two thin circular discs of mass m and 4m having radii of a and 2a respectively are rigidly fixed by a massless rigid rod of length 1 24 a through their centers This assembly is laid on a firm and flat surface and set rolling without slipping on the surface so that the angular speed about the axis of the rod is The angular momentum of the entire assembly about the point O is L see the figure Which of the following statement s is are true ee dvanced 016 m 4m A The center of mass of the assembly rotates about the z axis with an angular speed of w 5 B The magnitude of angular momentum of center of mass of the assembly about the point O is 81 ma a C The magnitude of angular momentum of the assembly about its center of mass is 17 ma 2

usceptibility is positive and large for a a paramagnetic substance b ferromagnetic substance substance c non magnetic d diamagnetic substance A compass needle which is allowed to move in a horizontal plane is taken to a geomagnetic pole It a stay in North South direction only b stay in East West direction only c become rigid showing no movement d stay in any position

For given PV diagram AB is isothermal at T temperature CD is also isothermal at T temperature given that T T2 Then which one of the following is correct P 5Po Po I D T Vo 2Vo T B C 4vo 5vo

You are given two converging lenses of focal lengths 1 25 cm and 5 cm to design a compound microscope If it is desired to have a magnification of 30 find out the separation between the objective and the eyepiece 2

A ball is thrown in vertically upwards direction with velocity 50 m s Maximum height covered by the ball will be g 10 m s

We wish to see inside an atom Assuming the atom to have a diameter of 100 pm this means that one must be able to resolve a width of say 10 pm If an electron microscope is used the minimum electron energy required is about 1 1 5 keV 3 150 keV 2 15 keV 4 1 5 MeV

Q10 For the circuit shown in the figure the value of R must be R www 1A 1 30 2 4 3 5 4 6 1 40 R 2 1A 12V 49 3 12V 352 4

Potential energy curve Sinusoidal is shown graphically for a particle The potential energy does not depend on y and z coordinates The maximum value of corresponding conservative force in magnitude for range 0 x 2 is n in Newton Find the value of n Take f 3 14 21 THE NALL GROUP 13 2 2 x meter AU Joule

B C J May be used as a rectifier because it offers a relatively low resistance for a forward bias and very high resistance for a reverse bias May be used as a rectifier because it offers a relatively high resistance for a forward bias and very low resistance for a reverse bias Cannot be used as rectifier May be used as a rectifion

RAI n angle 90 the resultant is 2k 1 p Q Prove that tan 0 b k k 1 bos 2 The resultant of the two vectors P and 2P is inclined at an angle with the larger one Show that c k 1 k 1 d k k 1 3 a 4 b 3 d 2 3245 c a k 1 k 1 b c 6 2 6i 2k

single layer conducting coil is wound with no gap between adjacent urns on a cylindrical frame of radius R Diameter of cross section of the vire used is d d R If breaking stress of the material of the wire is b at what magnitude of current will the coil rupture

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

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

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

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

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

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

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

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

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

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