Physics Questions

D 13 The stopping potential V in volt as a function of frequency The work function of sodium from the data plotted in the figure will be Given Planck s constant h 6 63 x 10 34 Js electron charge e 1 1 95 eV of line 1 0 6 4 1014 1 0 y o y 2 x 27 04 3 0 12 0 Vo 1 0 2 1 82 eV 2 2 4 v 10 Hz x 4x10 4 No Do 8 6 10 3 1 66 eV Jo 1 6 x 10 19 C JEE Main 2019 4 2 12 eV J

In a common emitter amplifier output resistance is 5000 2 and input resistance is 2000 92 If peak value of signal voltage is 10 mV and 50 then the peak value of output voltage is 1 5 x 106 volt 2 2 5 x 104 volt 3 1 25 volt 4 125 volt

Q7 In a fixed volume container ideal monoatomic gas is kept at room temperature 300 K To what temperature should the container be heated so that the final rms velocity of the gas molecules increases four times the initial velocity O A 1200 K O B 6000 K O C 4800 K O D 3600 K

onsider the charge configuration and a Gaussian surface as shown in figure If 2 and 3 are net electric flux due to charges 9 92 and q espectively then Here 91 92 and 93 all are different and non zero charges q 93 Gaussian surface

1 A rectangular loop has a sliding connector PQ of length 1 and resistance R 22 and it is moving with a speed v as shown The set up is placed in a uniform magnetic field going into the plane of the paper The three currents I I and I are P RQ RQ RO 12

14 A concave mirror is placed on a horizontal table with its axis directed vertically upwards Let O be the pole of the mirror and C its centre of curvature A point object is placed at C It has a real image also located at C If the mirror is now filled with water the image will be 1 real and will remain at C 2 real and located at a point between C and 3 virtual and located at a point between C and O 4 real and located at a point co

The following diagram indicates the energy levels of a certain atom where the system moves from 4E level to E a photon of wavelength is emitted The wavelength of photon produced during its transition from 7 E level to E is The ratio 3 4E E 9 735 3 will be 20 7

A silver ball of radius 4 8cm is suspended by a thread in the vacuum chamber UV light of wavelength 200 nm is incident on the ball for some time during which a total energy of 1 107 J falls on the surface Assuming on an average one out of 103 photons incident is able to eject electron number of photo electron ejected are 1 10 1 2 106 3 108 4 10 2

12 In the experiment of the meter bridge if length corresponding to null deflection is x what would be its value if the radius of meter bridge wire is doubled 1 x 3 4x 2 4 2x

10 The reading of voltmeter in the figure shown is 2002 www 100 V 1 50 V 3 40 V 100 2 300 600 2 60 V 4 80 V

Two balls of same mass and carrying equal charge from a fixed support of length 1 At electrostatic equilibrium assuming that angles made by each thread is small the separation x between the balls is proportional to 2013 A I C 12 3 B 1 D 11 3

An oceanographer observes that the density of ocean water increases by 0 001 grams per cubic centimeter every 300 meters below sea level If a cubic meter of ocean water at sea level has a mass of 1 027 kilograms what is the density of ocean water in grams per cubic centimeter at 900 meters Note Density is mass divided by volume 1 kilogram 1 000 grams 1 meter 100 centimeters A 1 030 B 103 C 10 3 D 1 03

SolveLancer Test The photon concept was confirmed by Compton Experiment Consider statements about this experiment 1 This experiment showed that photon model applied only to UV light ii The collision between X ray photon and electron is Inelastic collision iii Compton effect is observable with Yellow light iv The scattered X ray photon has less frequency Select correct option SolveLancer Test a Both 1 and iii correct b Only ii correct c Only iv correct d Both ii and iv correct a Ob

The efficiency of the cycle shown below in the figure consisting of one isobar one adiabat and one isotherm is 50 The ratio x between the highest and lowest temperatures attained in this cycle obeys the working substance is an ideal gas A x ex 1 B x ex 1 C x ex 1 D x ex 1 P isobar isotherm adiabat V

40 A mirror produces on a screen an image of the sun 2 cm in diameter If the sun s disc subtends an angle 0 1 radian on the surface of the earth then the radius of curvature of the mirror will be 36 10 5x0 For To 1800 1 20 cm 3 200 cm 40 cm 4 400 cm

While standing in an elevator you see a screw fall from the ceilling of elevator The celling of elevator is 5 m above the floor of the elevator The elevator is moving upward with a constant speed of 4 m s How long does it take for the screw to hit the floor g 10 m sec

Find the current through 102 resistor shown in figure 1 Zero 3 2 A 392 www 4 5 V HH 102 3 V www 692 www 2 1 A 4 5 A

3 4 4 9 10 Weight of a body decreases by 1 5 when it is raised to a height h above the surface of earth Whe same body is taken to same depth h in a mine its weight will show 1 0 75 increase 3 0 decrease 2 4 1 5 decrease 3 0 75 decrease

If mass of earth decreases by 25 and its radius increases by 50 then acceleration due to gravity at surface decreases by nearly 1 89 3 33 2 67 4 11

8 Two point objects of mass 2x and 3x are separated by a distance r Keeping the distance fixed how mu mass should be transferred from 3x to 2x so that gravitational force between them becomes maximum 1 3 x 4 X X 2 2 4 X 3 2x 3

A bob of mass m 10 kg hangs by a light inextensible string which is connected with a rigid support after passing over a smooth pulley P If the bob is released from an angular position 0 30 at the given pc P The force exerted by the string on the pulley is 50 3N The net horizontal force exerted by the string on the mass is 25 3N The force exerted by the string on the wall is 50 3N Acceleration of the bob at given instant is zero

1 A spherical raindrop of initial mass Mo and initial radius R falls freely from rest Let p be the constant density and r the radius at time t Assume that the drop maintains it s spherical shape The drop loses mass at the rate dm dt 47kpr where k is a constant Define te R Select the correct statement s 1 The speed of the drop at time te 2 is 15gR 8k 2 The rate of mass loss goes to zero as time ttc 3 The drop loses all it s mass in time te 4 The momentum approaches MogB 4k as t to

SolveLancer Test A coil consisting of 400 turns is rotated with an angular velocity of 600 rpm in a magnetic field of magnitude 0 4 mT about a diameter normal to the field The resistance of coil is 8 and its area is 80 cm Find the average emf developed in half a turn from a position where the coil is normal to the magnetic field SolveLancer Test a b c d 51 2 mV 25 6 mV 38 4 mV 31 2 mV

Test 6 Code A 4 A galvanometer has a resistance 100 2 It give full scale deflection on passing 10 mA curren through it To convert it into a voltmeter of range 0 10 V the resistance to be added in series is 1 8000 2 2 900 2 3 110 2 4 90 2

3 2 The youngs modulus of a rubber string 8 cm long and density 1 5 kg m is 5 x 108 Nm2 is suspended on the ceiling in a room The increase in length due to its own weight will be 1 9 6 106 m 2 9 6 10 m 39 6 x 10 11 m 4 9 6 cm platform is suspended 1

n 1 n 3 n 1 5 A total charge of 20 C is divided into two parts placed at some distance apart If the charges experience maximum coulombian repulsion then the charges should be 1 5 C 15 C 2 10 C 10 C 3 12 C 8 C 40 20

In the above figure a block of mass m is given a initial velocity v A force acts on m in negative direction Magnitude of force F um Which of the graph shows correct variation of velocity with time SolveLancer Test a b O d a b 0 m V ve

Figure shows an imaginary cube of edge L 2 A uniformly charged rod of length L moves towards left at a small but constant speed u At t 0 the left end just touches the center of the face of the cube oppositei it Which of the graphs shown in figure 30 Q2b represents the flux of the electric field through the cube as the rod goes through it flux G L 2 V a L b L 2 d b V L a C time

Sir ere ame from 8 and 1 When two thin lenses are in contact their combined power is 9 D When they are 27 separated by a small distance of 20 cm their equivalent power becomes D Their individuals power in dioptre is 6 and 3 5 and 4 7 and 2 Solution Answer 2 P1 P 9 27 P P 5 M 20 100 his P P ked Torr TO 2 7 9 1 PP P P 18 5 P P P P 4P P2 81 18 4 C

ime plot for a certain body is shown in the following graph In an interval from 5 s to 10 s the body is displaced by 25 m The work done by the force will be SolveLancer Test P 30 W 18 W a D 5 s 160j a b 120 J c 240 J d 320 J b 1 10 s

If an object is moving at constant acceleration in a straight line its instantaneous velocity half way through any time interval is 2 1 greater than its average velocity less than its average velocity equal to its average velocity 9 64 3 bu 4 half of its average velocity 942 5 000 8 3 5

Two point dipoles of dipole moment p and p2 are at a distance x form each other and p P2 The force between the dipoles is 1 4P P2 A 4 o X 1 6P P2 x4 41 0 B D 1 3 P P2 4 X 1 8 P1P2 41EO 2013

If an emitter current is changed by 4 mA the collector current changes by 3 5 mA The value of will be 1 0 5 3 0 875 7 Correct Answer 1 Status unattempted 4 3 5

57 Water rises in a capillary upto a height of 4 cm If it is titled to 30 from the vertical then the length of water column in it will be 4 cm 3330 i 8 1 cm 2 8 3 cm 3 4 cm 4 2 cm

3 In the potentiometer circuit shown in figure the internal resistance of the 12 V battery is 1 2 and length of the wire AB is 100 cm When CB is 60 cm the galvanometer show no deflection The emf of cell E is the resistance of wire AB is 3 2 A 1 3 6 V 3 3 V E 12 V 20 2 2 4 V 4 4 5 V B

3 4 Electric charges are distributed in a small volume The flux of the electric field throught a spherical surface of radius 10 cm surronding the total charges is 25V m The flux over a concentric sphere of radius 20 cm will be A 25 V m D 200 V m B 50 V m C 100 V m Figure shows an imaginary cube of edge L 2 A uniformly charged rod of li at a small but com

Two blocks A and B each having a mass of 480 gm connected by a light string passing over a smooth light pulley The block A is attached to a spring of spring constant 60 N m whose other end is fixed to a support 40 cm the horizontal surface as shown Initially the spring is vertical and unstretched when the system is released to move Find the velocity of the block A at the instant it just breaks off the surface below it take g 10 m s 154 m s 1 44 m s 1 34 m s O 164 m s eeeeeeeee m m B

5 The temperature of sink of Carnot engine is 27 C Efficiency of engine is 25 Then temperature of source is uchun f25 1 227 C 2 327 C 3 127 C 4 27 C

0 An observer is moving towards a stationary sound source If speed of observer is increased by 20 then percentage change in the wavelength of sound as observed by observer is Ich tech for saft frit af 20 da dech ari fed caft 1 10 rada 2 20 3 25 4 zero

A charge particle is revolving around a central charge with frequency 2 x 1015 Hz Find current due to motion of charge particle radius of orbit is 0 6 A q 2 x 10 18 C m 2 x 10 30 kg 1 1 MA 2 4 mA 3 4 x 10 5 A 4 zero

SolveLancer Test A coil of 350 turns having cross section area 1 4 m The coil is placed in a region where magnetic field changes from 0 50 Wb m to 0 98 Wb m uniformly in 0 08 seconds The induced emf is applied in a wire of 200 ohm The value of heat produced in the wire in 10 seconds is SolveLancer Test a 56 02 x 10 J b 21 98 x 10 J c 4 32 x 105 J d 6 88 x 105 J a b

SolveLancer Test The world s biggest aircraft Antonov AN 225 Mriya has an approximate wingspread of 100 m It travels from Ukraine in the east direction with a speed of 200 ms When it flies over a particular city the earth s total magnetic flux density is observed to be 0 4 mT and the dip circle on the aircraft measures the dip angle at that place as 60 The potential difference developed across the ends of the wings is SolveLancer Test a 4 00 V b 6 93 V c 3 47 V d 1 73 V

A block is released from rest on an fixed incline plane from a height 6m above the ground as shown in figure where coefficient of friction between block and incline plane is 0 5 Choose the correct option s for motion of block from shown position to the bottom of incline Change in potential energy is 300 J Work done by normal is 400 J Work done by friction is 200 J Final velocity of block when it just reaches to bottom of incline plane is 2 10 m s 6m 5kg fixed 37

A transparent solid cylindrical rod has a refractive index u and is surrounded by air A light ray is incident at mid point of one end of rod as shown If 0 is angle of incident then u for grazing a light along the walls is sine 2 3 0 1 3 W W N Z 1 3 2 1 O 4 3

53 In the circuit shown figure if the current distribution remains unchanged on connecting E then the valu of E will be f fack 1 12 Volt 2 6 Volt 60 ww 120 892 ww 100 ww E 3 4 Volt 4 2 Volt

Two small equal point charges of magnitude q are suspended from a common point on the ceiling by insulating massless strings of equal lengths They come to equilibrium with each string making angle 0 from the vertical If the mass of each charge is m then the electrostatic potential 1 k at the centre of line joining them will be 41 0 A 2 kmgtano L C 4 kmg tan0 B kmgtan0 D kmgtan0 2013

500 A particle is projected with speed u at an angle 8 with the vertical Change in speed of the particle when it reaches the highest point of trajectory from starting point will be ucose 2 usine 3 u cose 1 4 u sine 1 72 m

1 A boat having length of 2 5m and breadth 2m is floating on a lake The boat sinks by 1cm when a man gets on it The mass of the man is 2 5m2m Ich fan 34 dl da te 1 cm gam 1 50 kg 2 60 kg 3 62 5 kg 4 70 kg

In the arrangement shown in the figure mA 1 kg and me 2 kg while all the pulleys and the strings are massless and frictionless At t 0 a force F 10 t starts acting over central pulley in the vertically upward direction The velocity of A in m s when B loses contact with floor will be F 10t o G

An object is projected from point O with initial velocity U in vertical plane A mirror Mforms the image of object as shown Time after which relative velocity of object w r t velocity of image is least U M E 30 30 3g 2U 3g U