Physics Questions

28 A radioactive nuclei with decay constant 0 5 s is being produced at a constant rate of 100 nuclei s If at t 0 there were no nuclei the time when there are 50 nuclei is a Is c In 2 s b 2 n 4 S d In 3 Intasambaul S

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

Velocity v time t graph of a particle moving along a straight lin is shown in the figure The average velocity of the particle from t to t 4 sis v m s 4 0 4 2 20 m s 10 m s O 5 m s Zero 4 t s

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

TT A man while sitting on an oscillating swing whistles at a frequency 1000 Hz The swing is oscillating with an amplitude radian about the mean position in a vertical plane Man is sitting over the swing which is at a distance of 2m from the point of suspension of the swing Another man standing just infront of the mean position of the swing hears the whistle The maximum frequency heard by the man standing in front of the swing is Speed of sound in air 332 m s Question Type Single Correct Type 1 2 3 1016 Hz 1007 Hz 1003 Hz

3 Zero 4 4E 25 The emf and internal resistance of single batter which is the equivalent to the combination of thre batteries as shown in figure are 6V 1 2V 30 3 20V 202 www 192 10V 202 www www 4V 202 2 3V 202 4 2V 2002

If a graph of Binding energy B A per nucleon versus mass number A looks like as shown in figure Then using the curve choose correct option s MeV B A 88 6 4 50 100 150 200 A Fusion of two nuclei with mass numbers 30 and 45 will have Q value of 99MeV Fission of nuclei with mass number 80 into two nuclei of equal mass number will have Q value of 256MeV Fission of nuclei with mass number 150 into two nuclei of equal mass number will release energy

25 Three identical charges are placed at the corners of an equilateral triangle If the force between any two charges is F then the net force on any one charge will be 1 2 F 3 3 F 2 2F 4 3F

The least count of a stop watch is s Two persons A and B use this watch to measure the time peri 5 of an oscillating pendulum Person A takes the time period of 30 oscillations and person B takes the ti period of 50 oscillations Neglecting all other sources of error we can say that Absolute error in measurement of one time period by A is greater than the of B B Absolute error in measurement of one time period by A is equal to that of B Accuracy in measurement of one time period by B is greater than that of A D Accuracy in measurement of one time period by A is equal to that of B

Please type the answer provided space without unit In a Audio headphones capacitor of capacitance 2 F is connected across the alternating voltage with r m value Vrms of 270 V to improve audio quality If the r m s current Ims in the circuit is 4 5 A Find 1 the Capacitive reactance of the circuit in ohm 1 0 Mark ii the frequency in Hz of the source voltage 1 0 Mario

When open pipe is closed from one end then third overtone of closed pipe is higher in frequency by 150 Hz than second overtone of open pipe The fundamental frequency of end pipe will be open MHT CET 2016 A 75 Hz 150 Hz C 225 Hz T1 B LIDT D 300 Hz

48 A linear rigid rod of mass m and length falls freely under gravity at an angular position a with vertical upward direction The rod makes inelastic impact with the smooth ground at end A Just after impact g g A 1 Acceleration of centre of mass is 3 sin 1 3 sin a 1 2 Acceleration of centre of mass is sin a 1 3 sin a 1 A The no 3 The acceleration of end A is B ration and A in 3g sin a cos a 1 3 sin a g sina cosa

37 Find the apparent depth of an object O placed at the bottom of a beaker as shown in which two tingeetquestoayers of transparent liquids are filled ace it s e is h 25cm h 15cm 1 20cm O P 1 5 H 2 5 2 24 60cm AA A

estions 9 and 10 Two coaxial pipes of radius 1m and 1 2 m are have a common horizontal axis A uniform solid spherical ball of radius 0 1m is fitted inside them as shown The inner surfaces are sufficiently rough so that there is no slipping any where On slight displacement the ball starts moving along the gap shown in the downward direction There are 2 possible cases A 1 The inner pipe is held fixed but outer pipe is free to rotate 2 The outer pipe is held fixed but inner pipe is free to rotate All the 3 bodies both pipes ball have same mass of 1kg When ball reaches the bottom the pipe which is free to rotate is rotating with angular 00 velocity Let it be o in 1st case w in 2nd case 00 5 6 B A 1 1 2m 5 6 B 1 1m 000 If the angular velocity of ball at the bottom in the 2 cases is 2 C 27 125 D 3 2 a respectively D 27 o

A particle is suspended by two identical strings as shown in the figure Now mass m is given a small displacement perpendicular to the plane of the triangle formed Choose the correct statement s yc cu ch faa seny ggar A464 Jkut A Achu nu 1 H wha m Affa Ayu u faz u km 4 21 43 543 CYCH A 2 B 2 5 71 C m 3 21 The period of oscillations of system is 3 31 9 A 2 3 31 g The period of oscillations of system is 310 g A 2 Correct Answer 31 9 The period of oscillations of system is Correct Answer independent of mass m Ac Kad Kid GWH3 m uz A4 75 D If the distance between the suspension points was kept constant and the length of the strings were quadrupled then the time period will be doubled uf Adda fa ut qwu a s Aua zu Ga Rutas ct atya fu

What type of ecological pyramid would be obtained with the following data NEET 2018 Secondary consumer 120 g Primary consumer 60 g Primary producer 10 g 1 Inverted pyramid of biomass 2 Pyramid of energy 3 Upright pyramid of biomass 4 Upright pyramid of numbers

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

sses m and m are connected by a string going over a clamped light smooth pulley In a typical arrangement figure 5 E7 m 300 g and m 600 g The system is released from rest a Find the distance travelled by the first block in the first two seconds b Find the tension in the string c Find the force exerted by the clamp on the pulley m 0 FEM m Figure 5 E7 Consider the Atwood machine of the previous

8a The electric potential at points in an xy plane is given by V 2 0 r 3 0 y2 In unit vector notation what is the electric field at the point 3 0 2 0

Among the following combinations of inductance L and resistance R in series the largest value of time constant is for L 1H R 20 L 1 H R 40 L 4 H R 20 L 8H R 20

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

Two identical breakers A and B contain equal volumes of two different liquids at 60 C each and left to cool down Liquid in A has density of 8 x 102 kg m and specific heat of 2000 J kg K while liquid in B has density of 103 kg m and specific heat of 4000 J kg K Which of the following best describes their temperature versus time graph schematically assume the emissivity of both the beakers to be the same 3 A 60 C T Exam com

The charge of a capacitor is O on the top plate only on both plates in the dielectric on the bottom plate only

36 4 Smaller normal reaction A force of 5 3x N acting on a body of 20 kg along the x axis displaces it from x to x 6 m The work done by the force 1 20 J 2 48 J 3 68 J

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

A truck is moving such that block of 1kg mass remain at rest w r t truck then Acceleration of truck is less than 5 m s Acceleration of truck must be greater than 20 m s If acceleration of truck is 25 m s2 then normal contact force between truck block is 25N If acceleration of truck is 20 m s2 then friction force between truck block is 10 N Truck 0 5 1kg

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

A non conducting solid sphere of radius r 0 5 m and mass m 2 5 kg has a charge of Q 10 C distributed uniformly over its volume If the sphere is rotated about a diameter with an angular speed of w 25 rad s Find the magnetic moment in Am and angular momentum in kgm s of the solid sphere m Solid sphere A 12 5 12 5 B 12 5 6 25 C 12 5 12 25

A ball is thrown vertically upward from the roof of a tall building with an upward speed of 15 m s Find the ball s velocity when it is 5 m above the building O 10 m s O 11 2 m s O 7 m s O there is no answer O 8 m s

A particle of mass m executes SHM with amplitude a and frequency n The average kinetic energy of particle is one complete oscillation is 1 4 ma n 2 27 ma n 3 ma n I 1 4 ma n A

1 A straight conductor of length ro carrying a current i is placed perpendicular to a long s conductor which carries a current i as shown in figure The force exerted by the segment of To on the long straight conductor is 1 Hiio In2 2T 2 Hii In2 TC 2r 3 Zero 4 2Hoii In2 TC

0 A ray of light is incident on a glass plate at the polarising angle 57 Then Given tan57 1 The reflected ray and transmitted ray both will be completely polarised 2 The reflected ray will be completely polarised 57 and the transmitted ray will be partially polarised 3 The reflected ray will be partially polarised and the transmitted ray will be completely polarised 1 Which of the following phenomena is not exameetquest 4 The reflected and transmitted both rays will partially polarised

32 A 30 V 90 W lamp is to be operated on a 120 V DC lines For proper glow how resistance in 2 should be connected in series with the lamp 1 40 3 20 V 30 2 10 4 30 301

Wave Optics 37 When angle of incidence on a material is 60 the reflected light is completely polarized The velocity of the refracted ray inside the material is 1 3 x 10 m s 2 3 x 10 m s 3 1 5 10 m s 38 Light from n incoherent sources of intensity 1 21 31 nl are super imposed in a region Resultant intensity at a point in the region of superposition will be 1 Zero 2 n 3 n n 1 2 4 Can not be determined 39 A spaceship is moving with a velocity 10 m s towards a star that emits radiations of wavelength 6000 A The wavelength of radiation received by the crew in the spaceship will be 1 4000 A 3 5500 A 4 x 10 m s 2 1 40 Two polariser have polarising directions parallel to each other so as to transmit maximum intensity By keeping one of the polariser fixed other rotated through different angles 0 The graph which represents the variation of transmitted intensity versus is mo 2 4500 A 4 6500 A 3 2 m Atmo 41 A star is emitting radiation of wavelength 5000A The star is approaching the earth with a velocity of 1 5x105 m s The change in the wavelength of the radiation as received on the earth is 1 25 A 2 100 A 4 Zero 3 2 5 A 42 When light of particular wavelength falls on a plane surface at an angle of incidence of 60 the reflected light becomes completely plane polarised The refractive index and the critical angle of the material are respectively 43 0 44 1 3 sin 3 3 sin 3 4 3 sin In a double slit experiment n fringes are observed to be formed on a screen placed at a distance D from the slits when light of wavelength is used Now the screen starts moving from rest with constant acceleration a Then the time after which the first maxima disappears from screen and the direction of motion of screen are respectively 2D n 1 1 2D n 1 heetquestion paper 2D n 1 2D n 1 2 away from slits towards slits away from slits Aakash Institute towards slits sin Between two coherent waves phase difference at a particular position is 1 Ap x A6 t 2 A t constant 3 Ap x 4 t constant 4 Ap x constant 45 Two coherent waves of intensities I and 41 superpose then the maximum and minimum intensities produced are 1 51 and 31 3 91 and 31 2 91 and 1 4 51 and 1 46 In young s double slit experiment the y co ordinates of central maxima and 10th maxima are 2cm and 5cm respectively When the YDSE apparatus is immersed in a liquid of refractive index 1 5 the corresponding y co ordinates will be 1 2cm 7 5cm 2 2cm 4cm 3 3cm 6cm 4 3cm 7 5cm 47 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

4 When a film of transparent material of thickness 2 5x10 3 cm is placed over one of the slit in YDSE The fringe pattern shifts by a distance equal to 20 fringes widths The R I of material of the film is 5000 A 1 1 25 3 1 40 In VD with light 2 1 35 4 1 50

Two blocks A and B of masses 5 kg and 10 kg respectively are pushed on rough surface The contact force between the blocks is g 10 m s TTT 1 20 N 90 NA Rough B 0 4 2 40 N N IT

Choose the correct statement s Newton s 1st law of motion is applicable only in inertial reference frame A reference frame moving with constant velocity with with respect to another reference frame implies that they both can either be inertial or both non inertial reference frame For action reaction pair first the action and thon ropotion takes plago 000

2 A particle of mass m having a charge Q enters into a circular region of uniform magnetic field of radius R with velocity v directed towards the centre The direction of the magnetic field is inwards Then the deviation in the path of the particle will be 1 tan BaR 2 0 1BqR my 3 tan 4 tan 1 3qR 3 58

A block of mass m is placed on wedge mass m shown in fig Find out magnitude of force F such tha block m remain stationary w r t wedge All surfaces are frictionless and acceleration due to gravity is g m m g sin 8 m g tan 8 m g tan e m m g tan e m

2 Two blocks A and B of mass 2m and m respectively are connected to a spring of spring constant k A horizontal force F 5mg is applied to block A as indicated If acceleration of block B at the instant is g then acceleration of block A at that instant is 1 2g 3 2g BooooooooAF Smooth 2 3g 4 3g

Consider a conductor of resistance 50 through which 31 25 x 1010 electrons a re flowing for 5 minutes Calcul ate the amount of current flowing throu gh it Also find potential difference acro ss it

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

ope 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 2 3 X X vzJgn Jezi ze gn

Question Type Multiple Correct A Q No 3 Marks 4 00 1 00 View In 10N between block have minimum value of u Ho V Then choose CORRECT statement Ho 0 1 Ho 0 2 A 2kg 3kg English V

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