Basic Physics Questions and Answers

31 Work done by force F to move a block of mass 2 kg from A to C very slowly is 76x J Force F is always acting tangential to path Equation of path AB is x 8 y and BC is straight line which is tangent on curve AB at point B u between block and path ABC is 0 5 Then the value of x is g 10 m s 1 2 y 4 0 0 2 3 10 2m 0 5 B 2 m

0 A particle of mass m moving along a straight line experiences force F which varies with the distance travelled as shown in the figure If the velocity of the 2F then its velocity at 4x is particle at x is 3 2F 2F 0 F AX 2 2 Foxo 4 none of these

QUESTION NO 22 Aditya started driving his car He increases the speed till 4 seconds and then he kept his card in constant speed for 6 seconds Then after he decreased the speed of the car up to another 6 seconds After reaching at the starting place he draws the speed time graph of his 16 seconds driving as shown below B KON D 4 10 Time s Speed m s A 6543210 C 16

Example 6 5 A block of mass m is placed on the inclined surface of a wedge as shown in Fig 6 249 Calculate the acceleration of the wedge and the block when the block is released Assume all surfaces are frictionless 772 M 0 Fig 6 249

In a resonance tube experiment a vibrating tuning fork is held above the open end water level is gradually pushed down The first the second resonances occur when the water level is 24 1 cm 74 1 cm respectively below the oper end The diameter of the tube is A 2 cm C 5 cm HOTE MHT CET 2019 4 cm 3 cm B 1 DY

Example 6 6 The mass of wedge shown in Fig 6 256 is M and that of the block is m Neglecting friction at all the places and mass of the pulley calculate acceleration of the wedge Thread is inextensible M 07 Smooth Fig 6 256

27 28 29 30 Question No 29 OX 31 32 A body is projected vertically upward from the surface of the earth the speed time graph is doi 33

Light rays can enter from flat circular surface of a transparent cylinder The minimum value of refractive index of material of cylinder is such that no ray can emerge from curved surface of cylinder Find R 20

Negative Marks In all other cases For Example If first third and fourth are the ONLY three correct options for a question with second option being an incorrect option selecting only all the the without selecting any incorrect option second option in this case will result in 2 marks Selecting only one of the three correct options either first or third incorrect option s second option in this case with or without selection of any correct option s will result in 1 marks A particle is projected from ground at an angle 9 At a certain instant the velocity vector of particle makes an angle a with horizontal dv g ofd gsince modulus of Tangential acceleration has magnitude of g sin a Normal radial acceleration g cos a

Acceleration of a particle which is at rest at x 0 is a A B D particle further comes to rest at x 4 particle oscillates about x 2 maximum speed of particle is 4 units all of the above 4 22 i s 2x i Select the correct alternative s

A wheel starting from rest is uniformly accelerated at 2 radis2 for 2 seconds It rotates uniformly for the next 2 seconds and is finally brought to rest in the next 2 seconds calculate the total angular displacement of the wheel

19 A property R of a circular disc of thickness dx dx and area A is defined as A same property R for the cylinder shown in figure dx 1 TV4 K 2KL TDd L 2 R k W D J 2KL D d d Find the

What is physics Name its various branches How are different sciences related to physics Give five examples to explain the relation of physics with technology 2 What are the various branches of physics Explain in brief the field of these branches 3 4 Describe in brief the scope and excitement in physics Max Planck said We have no right to assume that any physical laws exist or if they have existed upto now that they will continue to exist in a similar manner in the future Comment 5 In the words of Bertrand Russel We know very little and yet it is astonishing that we know so much and still more astonishing that so little knowledge can give us so much power Justify the statement 6 In the Alexan compre Comm 7 Scien unders a few 8 Wha prop kinc 9 Stat and ap

11 A uniform thin rod of length 4a 2a and of mass 4m 2rm is bent and fabricated to form a square surrounded by semicircles as shown in the figure The moment of inertia of this frame about an axis passing through its centre and perpendicular to its plane is Olympiad 2014 stage 1 4 2 ma 3 A B 4 ma 2 C 4 3 ma 3 D ma 10 3 3

The vibrations of a string of length 60 cm fixed at both ends are represented by displacement cos 96 t where x and y are in cm TUX y 4sin 15 and t in second The particle velocity at x 22 5 cm and t 0 25 s is CAS C zero 1 100 cm s B D MHT CET 2019 4 x 96 cm s 1 1 96 cm s

A dumbbell is constructed by fixing small identical balls at the ends of a light rod of length 1 The dumbbell stands vertically n the corner formed by a frictionless wall and frictionless floor When it is slightly disturbed the dumbbell begins to slide and he lower ball moves towards right At the instant when the upper ball leaves the wall mass of each ball is m

0 In compound microscope the magnification is 95 to least distance of ditinct vision and the distance of object from objective lens is 1 3 8 cm and focal length of objective is cm What is the magnification of eye piece when final image is formed at least distance of distinct vision 1 5 2 10 3 100 4 None of these nes

A short magnetic dipole of magnetic moment 1 44 Am is placed horizontally with its north pole pointing towards north The distance of the neutral point from the dipole if the horizontal component of earth s magnetic field is 18 T is 1 20 cm 2 40 cm 3 10 cm 4 50 cm

A transformer with 40 turns in its primary coil is connected to a 120 V AC source If 20 W of power is supplied to the primary coil ho w much power is developed in the secondary coil a 10 W b 20W c 80W d 160W

View In English If initially flux through hemisphere is zero Now q and q2 placed according to figure Due to which charge flux through hemisphere will change 9 2 Correct Answer 1 Your Answer 4 Status incorrect Only 91 Only 92 Both None Add to Bookmark List 92

Match the following crystal structures with their atomic packing fraction p BCC 1 0 74 q FCC 2 0 34 r Diamond 3 0 52 s Simple Cubic 4 0 68 a p 3 q 1 r 2 s 4 b p 3 q 2 r 1 s 4 c p 4 q 2 r 3 s1

0 Which of the following phenomenon exemplify the conservation of charge 1 Pair annihilation 3 Nuclear reaction 2 Pair production 4 All of these

29 A conducting sphere has surface charge density o 1 7708x10 7 C m The magnitude of electric field just outside the surface is 8 854 10 2C N m 1 1 2 104 N C 2 2 0 104 N C 3 2 8 104 N C 4 3 1 104 N C

Aakash Institute 24 A light of wavelength 5000A is coming from distant star What is the limit of resolution of a telescope whose objective has a diameter of 200cm 1 3 05 x 10 7rad 2 6 6 x 10 7rad 3 8 x 10 7rad 4 2 23 10 rad 25 A poloroid sheet and an analyzer are placed such 30 that their transmission axes are parallel The analyzer is then rotated by 22 5 What is the intensity of the transmitted light as a fraction of intensity of light incident on analyser 1 0 45 2 0 68 4 0 87 3 0 41 26 The observed wavelength of light coming from a distant galaxy is found to increase by 0 5 as compared with that coming from a terrestrial source The galaxy is 1 Stationary with respect to earth 2 Approaching earth with a velocity of 1 5 10 m s 3 Receding from earth with velocity of light 4 Receding from earth with a velocity equal to 1 5 x 108 m s 27 In young double slit experiment D equals the distance of screen from slits and d is the separation between the slits The distance of the nearest point to the central maxima where intensity is same that due to a single slit is equal to DA 1 3 1 DX 3d Telegram reetque s double slit experiment is performed with light of wavelength 5000 A If a glass plate of thickness 1 m and refractive index 1 5 is kept in front of one of the slits then number of fringes that passes through the field of view is 1 1 3 3 2 2 4 4 4 34 In YDSE distance between two slits is 4 mm D 1 m and 12000 A If intensity of coherent light from two slits are l and 16 l then find intensity at y 0 1 mm on the screen 28 Consider the arrangement shown in figure The distance D is large compared to the seperation d between the slits A monochromatic beam of light of wavelength falls on the slit as shown Find the 1 7 2 10 4 16 3 13 distance x at which the first order bright fringe is 35 Two polarising sheets are placed with their planes formed parallel so that light intensity transmitted is maximum Through what angle must either sheet be turned so that light intensity drops to half the maximum value Incident ray 3 AD 2 I 2 DX 2d 2 D d D 2 D d screen AD d 3 4 29 Angular width of central maximum in the Wave Optics illuminated by the light of wavelength 6000 A If slit is illuminated by light of another wavelength angular width decreases by 30 wavelength of light used is 32 1 3500 A 2 4200 A 4 6000 A 3 4700 A A person with normal vision can just resolve two poles separated by a distance of 10m If the limit of resolution be 1 then the distance of the poles from the person is 1 34 km 3 34 m 2 3 4 km 4 3 4 m 31 A ray of light is incident on the surface of a glass plate of refractive index 3 at the polarising angle The angle of refraction is 1 60 3 45 When a thin film is illuminated by a parallel beam light of wavelength 6000 A of 7 fringes are observed in a certain region of the film How many fringes will be observed in the same region of the film if light of wavelength 4200 A is used 1 6 1 30 3 60 2 30 4 50 36 The intensity ratio H 2 10 4 18 2 45 4 90 of the two interfering waves in a Young s experiment is 4 The ratio resulting wave is 1 4 1 2 2 1 min in

are fixed at both ends String A has twice the length twice the diameter twice the tension and twice the density of string B The overtone of A that will be in unison with fundamental frequency of Bis 1 4th 3rd 3 1st JB 4 Ja 4 2nd 39 A uniform rope having mass m hangs vertically from rigid support A transverse wave pulse is produced at the lower end The frequency of wave pulse varies with x from the lower ends as 1 O 1 2 40 The first overtone of an open organ pipe has frequency f The second overtone of a closed organ pipe of the same length will have frequency neglect end corrections f 2 5f 4 v Jgn 3f 2 4 Jgn Vz 21 3f 4 41 The equation of stationary wave is sin 100 where x is in cm and TL X y 10 cos 10 t is in s The wave is formed on a string of length 40 cm An antinode will be located at from the 1 x 15 cm 2 x 25 cm 3 x 20 cm 4 x 12 5 cm 42 A motor cycle starts from rest and accelerates along straight path with an acceleration of 4 m s2 away from a stationary electric siren How far the motor cycle must have travelled when the rider hears the frequency of siren at 90 of its value when motor cycle was at rest speed of sound 330 m s 1 136 m V 2 156 m 3 76 m 196 mi TO 43 The equation of a travelling wave on a string moving in positive x direction is given by y Asin of kx It is reflected from a rigid Fi boundary at x 0 The equation of rellected wave is y 1 Asin ot kx 2 Asin ot kx 3 Asin ot kx 3 particle at t s will be 2 V 4 Acos t kx 44 The velocity time v t graph of a particle executing S H M is shown below The acceleration of the 1 cm s 5 cm s 2 5T 3 2 5T 3 2 0 cm s 3 v r 4 F V cm s cm s 3 g 6 997 100 vtu 2 av cos 90 O Costo 20 9 330 330t 5T 3 6 y 4 Zero J5 J 45 Which of the following quantity is always negative in S HM2 meanings Fr t s 1 51 t max 3

A pipe closed at one end has length 83 cm The number of possible natural oscillations of air column whose frequencies lie below 1000 Hz are velocity of sound in air 332 m s A 3 C 5 B D MHT CET 2018 4 6

E 2d 3 2D 3 d 48 A parallel beam of mono chromatic light of wavelength 5000 A is incident normally on a single narrow slit of width 0 001 mm The light is focused by a convex lens on a screen placed on the focal plane The first minimum will be formed for the angle of diffraction equal to 60 1 30 2 4 0 3 15 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 10 4 rad 3 5 1 x 10 4 rad 2 4 1 10 rad 4 6 1 x 10 4 rad 50 A ray of light is incident on a glass plate at the polarising angle 57 Then Given utan57 1 The reflected ray and transmitted ray both will be completely polarised 2 The reflected ray will be completely polarised and the transmitted ray will be partially polarised 3 The reflected ray will be partially polarised and the transmitted ray will be completely polarised 4 The reflected and transmitted both rays will partially polarised 51 Which of the following phenomena is not by Huygen s construction of wavefront 1 Refraction 2 Reflection 3 Diffraction 4 Origin of spectrum 52 The equivalent path length in air for thickness t of a medium of refractive index u is 1 ut 2 u 1 t 1 t 14 3 53 When a YDSE is performed using a monochromatic source of light fringe width is found to be 1 2 mm The minimum distance above central maxima at which intensity is th of the maximum value is 1 0 1 mm 2 0 2 mm 3 0 3 mm 4 0 4 mm 54 The intensity ratio for the two interfering beams of light is B What is the value of maxmin min 55 5 56 1 B 2 3 1 B 3 2R 57 A beam of light strikes a piece of glass at an angle of incidence 60 and the refracted beam is completely 1 1 5 2 3 Tele questione polarised The refractive index of the glass is 4 Light from a sodium lamp 590 nm is diffracted by a slit of width d 0 30 mm The distance from the slit to the screen is D 0 87 m The width of central maxima will be 1 3 9 mm 2 3 4 mm 4 4 mm 3 3 0 mm In an electron microscope if the potential is increased from 20 KV to 80 KV the resolving power of the microscope will change from R to 1 RI4 2 4R RIN 3 2 4 2 58 A star is going away from the earth Then it shows 1 Red shift 2 Blue shift 3 Yellow shift 4 Green shift 59 Two light sources are coherent when 1 Their amplitudes are equal 2 Their frequencies are equal 3 Their wavelengths are equal 4 Their frequencies are equal and their phase difference is constant 60 In a Young s double slit experiment using a monochromatic light the fringe width is 4 mm Now the whole arrangement is dipped in water Then the fringe width will be now 1 4 mm 3 3 mm 2 2 mm 4 6 mm

2 A given length of a sonometer wire is in resonance with tuning fork If length of wire is reduced by 5 the wire vibrating with the fork produce 4 beats s The frequency of the tuning fork will be 1 76 Hz 2 95 Hz 3 56 Hz 4 80 Hz

A thin uniform rod of length 4 I mass 4m is bent at the points as shown in the fig What is the moment of inertia of the rod about the axis passing point O perpendicular to the plane of the paper me B 10 me 90 90 C m 2 12 D me 24

In the given diagram if the spring connecting D and C is cut then what will be the accelerations of blocks A B C D at that instant 1111 0000 0000 4kg C3kg B2kg 0000 A 1kg

A particle is projected from ground at an angle 8 At a certain instant the velocity vector y of particle makes an angle a with horizontal g modulus of V dt gsina Tangential acceleration has magnitude of g sin a Normal radial acceleration g cos a

76 In Young s double slit experiment two slit are d distance apart Interference pattern is observed or screen at a distance D from the plane of slit A bright is observed on the screen directly opposite to one of the slits The wavelength of light is 1 3 D 2d D 2 d 2D d

block of mass m is placed on wedge mass m shown in fig Find out magnitude of force F such that block m remain stationary w r t wedge All surfaces are frictionless and acceleration due to gravity is g m m

A uniform rod AB is placed which makes an angle with the floor Now end point B of rod is pulled with a horizontal velocity 10 m s as shown Taking the length of the rod as the velocity of CM of the rod At the instant when 53 is AAAAAAAAAAAA e B A 12 5 m sec 25 4 C 6 m sec A 10m s m sec D 25 m sec

2 15 A circular coil A has a radius R and current flowing through it is I Another circular coil B has a radius 2R and if 21 is the current flowing through it then the magnetic fields at the centre of the circular coil are in the ratio i e BA to BB of a 4 1 b 2 1 c 3 1 d 1 1

Q 43 Option 1 9PoVo An R Option 2 3PoVo 2n R Option 3 9PoVo 2n R Option 4 9PoVo nR n moles of an ideal gas undergoes a process A B as shown in the figure The maximum temperature of the gas during the process will be 2Po Po A B Vo 2Vo V

A photoelectric surface is illuminated successively 2 2 by monochromatic light of wavelength 2 and the maximum kinetic energy of the emitted photoelectrons in the second case is 3 times that in the first case the work function of the surface of the material is h Planck s constant c speed of light Re AIPMT 2015 1 3 hc 32 hc a 2 4 hc 22 CAU 2hc If

21 An a particle moves in a circular path of radius 0 83 cm in the presence of a magnetic field of 0 25 Wb m The de Broglie wavelength associated with the particle will be AIPMT Prelims 2012 1 10 A 3 1 2 0 01 A 4 0 1 A

Boy A B and C are moving with constant velocities as shown in diagram A VPQ 5 m s 5 2 m s VAB 51 VBC 51 101 VCA 51 51 VCE 5 10 45 B it shows velocity of P w r t Q C 5 m s L Ay X

34 A plane mirror rotating at an angular velocity 4 radian s reflects a light beam The angular velocity of the reflected beam is 1 2 rad s 3 8 rad s 2 6 rad s 4 4 rad s

A town is getting 800 kW electric supply from a step down transformer at 400 volt Turn Ratio 10 1 The electricity is supplied from H T Line from a power plant generating 400 volt AC The A C is step up at plant to reduce line losses and then it is transmitted by H T line of total resistance 20 Q Find configuration of step up transformer A B 500 7000 volt D 600 9000 volt C 400 8000 volt 700 3000 volt

53 When a YDSE is performed using a monochromatic source of light fringe width is found to be 1 2 mm The minimum distance above central maxima at which 60 intensity is th of the maximum value is 1 0 1 mm 3 0 3 mm 2 0 2 mm 4 0 4 mm

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

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

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

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

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

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