Basic Physics Questions and Answers

1 A point charge Q is placed just outside an imaginary hemispherical surface of radius R as shown in the fig Which of the following statements is are correct JEE Adv 2017 Paper K 1 A The electric flux passing through the curved surface of the hemisphere is 200 B The component of the electric field normal to the flat surface is constant over the surface C Total flux through the curved and the flat surfaces is D The circumference of the flat surface is an equipotential Eg

minimum size of the plane mirror fixed on the wall of a r om in which an observer at the centre of the room can se e the full image of the wall behind him is one third the he ght of the wall plz expalin it through figure

Figure shows three resistor configurations R1 R2 and R3 connected to 3V battery If the power dissipated by the configuration R1 R2 and R3 is P1 P2 and P3 respectively then 102 A B 10 C 192 R1 Select an answer 102 P1 P2 P3 P1 P3 P2 3V P3 P2 P1 192 192 www 192 192 192 www R2 3V 122 www 122 192 R3 3V

Arrange the following gases in increasing order of tendency of adsorption H O2 CO2 SO2 Hz Oz COz SO SO2 CO2 Oz H2 COz SOz Oz H2

If R a b c d and percentage error in measurement of a b c and d are 0 1 0 2 0 3 and 0 4 respectively then the maximum percentage error in R is NCERT Pg 27 1 1 9 3 2 9 2 3 1 4 4 0

In all the cases discussed below we connect a battery of negligible internal resistance across the terminals Capacitor and inductor are ideal then D ww TRRRRRRR WWW R HH L 00000000 P R B Multiple options may be correct equivalent resistance across AB at t 0 is 2R equivalent resistance across AB at t is R 2 equivalent resistance cross P1P2 at t 0 is R

Two particles of equal charge after being accelerated through the same potential difference enter in uniform transverse magnetic field and describe circular paths of radi R and R respectively Then the ratio of their masses m m is R R R 2

A bullet of mass m fixed with velocity u penetrates upto thickness d into the block if block is fixed Now if block is free to move on smooth ground and bullet is fired into it symmetrically with same velocity u it penetrates upto thickness d Assume resistance force due to block on bullet in both case is same Find ratio d d if m M mu 777777 m

Two capacitors of 2 F and 3 F are charged to 150 volt and 120 volt respectively The plates of capacitor are connected as shown in the figure A discharged capacitor of capacity 1 5 F falls to the free ends of the wire Then 1 5 F o H 150V 2 F 3 F A 120V A Charge on the 1 5 F capacitors is 180 C B Charge on the 2 F capacitor is 120 C C Positive charge flows through A from right to left D Positive charge flows thorugh A from left to right

infinitely long straight wire carrying current 1 4A as shown in figure What will be the total magnetic flux crossing through the rectangular loop I 0 531 Wb 0 324 Wb 4 m B A 2 m C 2 m D

A non conducting disc of mass m and radius R has total charge Q which is uniformly distributed over its surface If it rotat with constant angular velocity w about its own axis i e axis passing through centre and perpendicular to its plane Then 0 Electric field at centre of disc is Q 4 ER HOQW 2 R The magnetic field at centre of disc is None of these The magnetic dipole moment of disc is QWR 2 4

25 A straight infinitely long cylinder of radius Ro 10 cm is uniformly charged with a surface charge density o 10 2 C m The cylinder serves as a source of electrons with the velocity of the emitted electrons perpendicular to its surface Electron velocity must be 105 m s to ensure that electrons can move away from the axis of the cylinder to a distance greater than 103

Consider the plane makes intercepts of 2 A 3A 4 A on the coordinate axis of the crystal with a b c 4 3 2 The crystal is orthorhombic crystal Calculate the miller indices of the given plane of the crystal A 4 1 1 B 4 3 2 C 4 2 1 D 4 4 4

19 Two students measure the weight of a 10 Kg mass using a spring balance and record these readings as Va A 10Kg 10Kg 10 5Kg 10 5Kg 9 5Kg B 10Kg 10 1Kg 10 1Kg 9 8Kg 9 9Kg Then 1 A and B both are equally precise 2 B is more accurate than A 3 Neither A nor B is accurate

The parameters for the following plot representing the rate of evaporation versus pressure on x y axis would be A B C y axis evaporation on x axis pressure on y axis x axis evaporation on y axis pressure on x axis both 1 2 None

2 18 We wish to observe an object which is 2 5 in size The minimum energy photon that can be used 1 5 KeV 3 10 KeV 2 8 KeV 4 12 KeV

Trajectories of two stones projected from level ground is shown Let T T be their time of flights and u U their speed of projection then T T1 U U 0 T T

A tortoise can run with a speed of 0 12 m s and is a hair can run 20 times fast In a race they both start at the same time but the hair stops to rest for 5 0 minutes The tortoise wins by a shell 35 cm

A wooden block W is suspended by using a cord from a heavy steel ball B The entire system is dropped from a height Neglecting air resistance the tension in the cord is A B C D Zero The difference in the masses of B and W The difference in the weights of B and W The weight of B

24 A mercury pallet is trapped in a tube as shown in figure The tube is slowly heated to expel all mercury inside it Isothermal condition Heat given to the tube is pHg 13 6 gm cc Atmospheric pressure 105 Pa cross section area of tube 2 cm 2 2 10 cm 5 cm 10 cm

32 A man is supplying a constant power of 500 J s massless string by pulling it at a constant speed of 10 m s as shown It is known that kinetic energy of the block is increasing at a rate of 100 J s Then the mass of the block is a 5 kg c 10 kg 60 m b 3 kg d 4kg

26 An isolated parallel plate capacitor is maintained at a certain potential difference When a 3 mm thick slab is introduced between the plates in order to maintain the same potential difference the distance between the plates is increased by 2 4 mm The dielectric constant of slab will be

A block attached to a spring pulled by a cons horizontal force is kept on a smooth surface shown in the figure Initially the spring is in natural state Then the maximum positive work the applied force F can do is Given that spring not break a F2 k 4F k 0000000 F 2F2 k 2

A half hollow cylinder of length 8 m has its cross section as shown in Figure below If the cylinder is made of carbon c 105 mhos m the resistance between the ends of the cylinder Ta 3 cm and b 5 cm W 7 57 Q 30 30 40 736 Q 15 1570

A particle is subjected simultaneously to two SHM s one along the x axis and the other along the y axis The two vibrations are in phase and have unequal amplitudes The particle will execute Question Type Single Correct Type 1 2 3 straight line motion circular motion elliptical motion 4 parabolic motion

22 Two blocks P and Q of masses 0 3 kg and 0 4 kg respectively are stuck to each other by some weak glue as shown in the figure They hang together at the end of a spring with a spring constant k 200 N m The block Q suddenly falls free due to failure of glue then the maximum kinetic energy of the block P during subsequent motion will be mJ freeeee P

18 A non conducting non magnetic rod having circular cross section of radius R is suspended from a rigid support as shown in the figure A light and small coil of 300 turns is wrapped tightly at the left end of the rod where uniform magnetic field B exists in vertically downward direction Air of density p hits the half of the right part of the rod with velocity v as shown in the figure What should be current in clockwise direction as seen from O in the coil so that rod remains horizontal Give answer in mA given 2 TRB 1 A 2 Lv V P B air V

A material particle is chasing another one and bot of them are moving on the same straight line Afte they start from a particular point their velocities u vary with time t as shown in the figure At what instant will they meet D m s A 10 s B 16 s 89 t s

A plane mirror of semicircular shape radius 1 m is placed in y z plane with its diameter along y axis and centre at origin An object is placed on the axis of mirror at a point 5 0 0 At a distance of 10 m from plane mirror there is a wall also parallel to y z plane Then what is the ratio of spot of light on wall to that of the mirror Z r 1m 5m y X

IfE amplitude of electric field B amplitude of magnetic field permeability of free space and e permittivity if free space then the speed of electromagnetic wave in vacuum is 1 1 3 H Ho E 2 B 4 Both 1 and 2

Which of the following order is correct A B C D Weak force Gravitational force Strong Nuclear Force Electromagnetic force Gravitational force Weak force Strong Nuclear Force Electromagnetic force Gravitational force Weak force Electromagnetic force Strong Nuclear Force Gravitational force Weak force Electromagnetic force Strong Nuclear Force

Given that R 20 R 30 and R3 60 Which of the following combinations will give an effective resistance of 4 Q Select an answer A B C D All in parallel R and R2 in parallel in series with R3 R2 and R3 in parallel in series with R R3 and R in parallel in series with R2

Region 1 z 0 contains a dielectric for which Er1 2 5 while region 2 z 0 is characterized by Er2 4 Let E2 30ax 50ay 70a V m then electric field intens None of these O O O 30ax 50ay 112az V m 30ax 50ay 28az V m

A sonometer wire of length vibrates in fundamental mode when excited by a tunning fork of frequency 416 Hz If the length is doubled keeping other things same the string will XVibrate with a frequency of 208 Hz Vibrate with a frequency of 312 Hz Vibrate with a frequency of 416 Hz String will stop vibrating

A particle is moving along path y x2 in x y plane with constant speed of 10 m s What will be its magnitude of acceleration when it is at x 0 Assume all the units are in Sl A Zero B 2 m s2 C 20 m s2 D 200 m s2

falls through 50 cm b instant 66 The pulley shown in figure 10 E11 has a radius of 20 cm and moment of inertia 0 2 kg m The string going over it is attached at one end to a vertical spring of spring constant 50 N m fixed from below and supports a 1 kg mass at the other end The system is released from rest with the spring at its natural length Find the speed of the block when it has descended through 10 cm Take g 10 m s eeeeee 1kg

A deuteron of kinetic energy 50 keV is describing a circular orbit of radius 0 5 m in plane perpendicular to magnetic fiel B The kinetic energy of proton that describe a circular orbit of radius 0 5 m in the same plane with the same magnetic field B is 200 keV 50 keV 100 keV 25 keV

A pendulum suspended from the ceiling of a train oscillates with a time period 2 second when the train is accelerating at 10 ms What will be its time period when the train retards at 10ms 2 Question Type Single Correct Type 1 2 3 2s 2 2s 2 2 s

Exercise 2 The angular spread of a particular laser beam is 0 10 rad Calculate the diameter of the spot formed on the Moon s surface if the laser is directed toward the Moon from the Earth The Earth to Moon distance is L 3 8 10 km Support the answer by diagram

A potentiometer wire of length 100 cm has a resistance of 10 Q It is connected in series with a resistance R and a cell of emf 2 V and of negligible resistance A source of emf 10 mV is balanced against a length of 40 cm of the potentiometer wire What is the value of R 790 Q 850 Q 720 Q 620 Q

Consider a region where both uniform electric and magnetic fields E and B are present both along the z axis A positively charged particle of charge q and mass m is projected from the origin with initial velocity V I Which of the following options are correct m 2mV qB qB A The y coordinate of the particle at time t is B The distances between two consecutive points on the z axis where the particle meets the z axis are in ratio of 1 3 5 and so on C The distances between two consecutive points on the z axis where the particle meets the z axis are in ratio of 1 4 9 and so on D The maximum x coordinate the particle is 2mV qB

A simple pendulum of length L has an energy E and linear amplitude A The energies of the simple pendulum i when the length is 2L with same amplitude A and ii when the amplitude is 2A but with the same length L are respectively Question Type Single Correct Type 1 2 3 2E 2E EE 2 2 E 2E

A pipeline 50 cm diameter takes off from a reservoir whose water surface 03 elevation is 145 m above datum The pipe is 4500 m long and is laid completely at the datum level In the last 1100 m of the pipe water is withdrawn by a series of pipes at a uniform rate of 0 075 m s per 250 m Find the pressure at the end of the pipeline Assume f friction fact or 0 017 and the pipe to have a dead end

Electric field lines of a portion of an electric field that is symmetrical with respect to rotation about y axis are shown in the figure A charge particles stays in equilibrium at point 0 10 If modulus of charge of the particle is changed gradually till it shifts to another equilibrium position 0 0 estimate fractional change in the charge modulus a 1 3 1 9 b 2 3 d 8 9 ual point charges 10 y cm 5 10

0 Ranvir and Akshay are rowing two boats in a river with the same speed v relative to the river Ranvir is upstream relative to Akshay The river is flowing with speed v 2 Each boat sends through the water a signal to the other The frequencies f of the generated continuous sonic signals are the same Each observer observes the wave sent by the other person In each of the situation in column I Match the appropriate entries Column I A B C D Ranveer Ranveer f rf v 2 Ranveer Ranveer V O Akshay Akshay Akshay Akshay P Column II The times it takes for the signals to travel from one boat to the other will be the same Q The wavelength observed by Akshay is greater than the wavelength observed by Ranvir 0 R The frequency observed by Akshay is greater than the frequency observed by Ranvir S The wavelength observed by Akshay is lesser than the wavelength observed by Ranvir T The frequency observed by Akshay is equal to

When mass m oscillates with spring of spring constant k its frequency is 3Hz and with spring of spring constant k its frequency is 6Hz Then frequency of oscillations when mass is connected with springs as shown in figure is Question Type Single Correct Type 1 2 3 6 7 4 5 k k oooo m vooo 9

The 238 U nucleus has a binding energy of about 7 6 MeV per nucleon If the nucleus were to fission into two equal fragments each would have a kinetic energy of just over 100 MeV From this it can be concluded that nuclei near A 119 has mass less than half that of 238U nuclei near A 119 have masses greater than half that of 238U nuclei near A 119 must be bound by about 6 7 MeV nucleon nuclei near A 119 must be bound by about 8 5 MeV nucleon

29 The 5 graphs shown in column II are plots of displacement from mean position at a given instant The arrows represent the direction of velocity of particles at that moment Match with description in column I Column I A Standing wave B Wave travelling along x 0 positive x P D Longitudinal wave Q C Wave travelling along x 0 negative x R S T Column II W All velocities are along negative x All velocities are along negative y 777 Half of the velocities are along negative y and other half are along positive y V Half of the velocities are along negative x and other half are along positive x X

A charged particle enters a transverse un magnetic field region in two different manners as shown in the figures Maximum speed for which the particle does not cross the magnetic field region onto the other side is v when it enters in manner 1 The maximum speed if it enters the field in manner 2 is X XOX 90 d Manner 1 1 v 2 fat v 3 X X 30 X 2 15v X Manner 2 4 2v X

39 When radiation of wavelength is incident on a metal surface the stopping potential is 4 8 volts If the same surface is illuminated with radiation of double the wavelength then the stopping potential becomes 1 6 volts Then the thereshold wavelength for the surface is 1 2X 2 4 3 6X 4 8 40 IF 10 of a radioactive material decays in 5 days then the 39 fa fafar va sarfed 12 for at afrost fava 4 8 volts anafaa fan are a farvi fava 1 6 volts tenere is for teens 1 2 2 4X 3 6X 4 8 40 10 20