Physics Questions

equal to R 39 If the mass of moon is M 9 81 earth find the distance of the point where gravitational field due to earth and moon cancel each between centres of earth and moon is 60 R where R is the radius of earth a 4 R c 12 R where M is the mass of b 8 R d 6 R

42 A particle of mass m is projected from ground with velocity v making an angle e with vertical Then the debroglie wavelength of particle at the highest point is 1 oc 2 h mv sin 0

The equivalent inductance of the given circuit across AB is O2L O O W P

11 A particle of mass 2kg is moving on a circular path of radius 10m with a speed of 5m s and its speed in increasing at rate of 3m s Find the force acting on the particle a 5N b 10 N c d 14 N 12 N

A current carrying long wire and the rod PQ are in same plane The rod moves parallel to the wire with a velocity v as shown Which of the following is correct about nduced emf in the rod O End P will be at lower potential with respected to Q OP and Q will be at same potential O There will be no induced emf in the rod O Potential at P will be higher than at Q 31 36 41 46 51 56 61 42 47 52 57 62 58 63 54 59 64

A ball is thrown vertically upward with a velocity u from the top of a tower If it strikes the ground with velo 3u the time taken by the ball to reach the ground is g 3u 2 4 2u g 4u

The wire loop of radius R shown in the figure carries an anticlockwise current I Magnetic field in x direction is constant in the region B The net torque on the current loop is along ve y axis The net torque on the current loop is along ve y axis The net magnetic force is into the page The net magnetic force is zero

A dip circle is taken to magnetic equator The needle is allowed to move in magnetic meridian the needle will stay In horizontal direction In vertical direction In any direction it is released how Come In any direction except vertical or horizontal If 2ph

A spherical shell of radius R carries a uniform surface charge do on the northern hemisphere and uniform surface charge 00 on the southern hemisphere Find the potential inside and outside the sphere calculating the coefficients explicitly up to A and B6

Why maximum kinetic energy The elec trons can be ejected from the surface a toms as well as the inner layer atoms However the probability of ejection of e lectrons from the surface is higher as t hey get more energy for emission of ele ctrons Thus we consider the maximu m kinetic energy The energy of electro ns decreases when they are struck by a gas particle present in the discharge tu be which cannot be predicted experim entally Hence we always deal with ma ximum kinetic energy

igure shows an L R circuit Value of current through the battery long time after closing the switch S is www R O O O 1 1x 18 V 3V 2R 2R 16 21 26 31 36 41 46 51

A particle located at x 0 at time t 0 starts moving along the positive direction with a velocity v which varies as v a x then acceleration of particle is a is a constant 2 a x 2 a x 2 V constant

Question 11 Width of a river is 60m A swimmer wants to cross the river such that he reaches from A to B directly Point B is 45m ahead of line AC perpendicular to river Assume speed of river and speed of swimmer are equal Swimmer must try to swim at angle 8 with line AC Value of 0 is 1 37 C B A 2 53 River Flow 3 30 4 16

onducting rod OA of length 2 I is rotated about its end O with an angular velocity in a uniform magnetic field B directed perpendicular to the plane of rotation The ential difference across its two ends is Bool2 2Bol 21 26 31 36 41 46 51 22 27 32 37 42 47 52 23 28 33 38 43 48 53 24 29 34 39 44 49 54

Pin P is attached to BC and slides freely in the slot of OA B Determine the rate of change d0 dt in rad s of the angle at the instant when h 4 m B 60 and 0 30 knowing that BC moves at a constant speed v 5 m s h No A C

wi arge q is endicular of the field ge particle 102 force 1 A positive charge projected past a piece iron 2 A positive charge sent along the axis of a solenoid e and a mean of 0 3 A 3 Two parallel wires carrying current in the same direction 4 A positive charge projected between the poles of a magnet 103 A straight wire of length metre is carrying a current of 2 A and the magnetic field due to it is measured at a point distance 1 cm from it If the wire is to be bent into a circle and is to carry the same current as before the ratio of the magnetic field at its centre to that obtained in the first case would be 1 1 100 8 1 50 2 100 1 4 50 1 104 Magnetic dipole moment is a 1 Scalar quantity Vector quantity for all magnets ont quantity 7623456

20 m long thin wire oriented in east west direction is falling with velocity 15 m s perpendicular to the magnetic field 0 3 x 10 Wb m2directed towards north The duced emf across the ends will be O 0 9 mV O 1 5 mV 900 V 0 09 V 21 26 31 36 41 22 27 32 37 42 23 28 33 38 43

The charges on the two plates initially at t 0 are Q and Q Long time after closing the key the charges on the outer and inner surfaces of plate 1 are respectively C capacitance of capacitor A Q 0 IF C Q Q Ce 2 B D Q Q2 2 C Q Q Q Q 2 2 1 8 S

3 A current element of strength 2x 10 Am placed at the corner A of a square ABCD of side 10 cm Magnetic field induction at the point which is at diagonally opposite corner of the square due to the element is The element lies along the side AB 1 0 7 x 10 9 Wb m 2 1 2 x 10 9 Wb m 3 2x 10 9 Wb m 4 Zero oving in a circular orbit of rac

Wind is blowing in the east direction at speed of m s which causes the rain to fall at some angle wit the vertical With what velocity should a cyclis drive so that the rain appears vertical to him A 2 m s south B 2 m s east D 4 m s south C 4 m s west OA B Correct Not Marked By You

7 Suppose a smooth tunnel is dug along a straight line joining two points on the surface of the earth and a particle is dropped from rest at its one end Assume that mass of earth is uniformly distributed over its volume Then a the particle will emerge from the other end with velocity GM V 2R respectively 9 where M and R are earth s mass and radius e b the overlapping will come to rest at centre of the tunnel c potential energy of the particle will be equal to zero at centre of tunnel if it is along a diameter d acceleration of the particle will be proportional to its distance from mid point of the tunnel ing in a circular orbit round the certain noin

questions place e g 06 25 07 00 00 33 00 30 30 27 27 30 If flux through a loop is given by 21 Wb then induced emf in the loop at r 2 s will be n volts Find the value of n Answer Port to the second dec 21 26 31 22 27

coil of resistance 30 and inductance 5 H is connected to a battery of emf 60 V The energy stored in the coil in steady state is n joules Find the value of n nswer

In a vessel at 101 3 kN m and 300 k the percentage relative humidity of the water vapour in the air is 25 if the partial pressure of the water vapour when air is saturated with vapour at 300 K is 3 6 kN m calculate The partial pressure of the water vapour in the vessel The humidity and the percentage humidity

tan a Velocity v versus time t graph of a particle moving in a straight line is shown in the figure If tan B becomes zero is v m s 02 m s 3 m s 4 mis BA t s 2 then average speed of the particle till the time its velocity

The network shown in figure is a part of the circuit At a certain instant the current is 1 2 A and it is increasing at the rate of 10 A s The potential difference between he points A and B VA Ve is n volts Find n R 20 E 12V L 5mH B WWW 80000 A 2A 26 31 36

The self inductance of coil does not depend upon The geometrical dimensions of the coll O The nature of medium inside the coil The flux or current flowing through the coll O Both 1 2

Which of the following is incorrect about Lenz s law It explains the physical significance of the negative sign in faraday s law O It is a consequence of conservation of energy O It tells about the transformation of mechanical energy into electrical energy O Lenz s law explains the force acting on current carrying element 21 26 2 31 E E 36

gure shows two concentric loops of radii r and r2 Mutual inductance of the arrangement is OM Ho 2r O ME 2x 25 OM Ho 21 OM H 4r 16 21 26 31 36 41 46 51 56 61 17 22 27 32 37 42 52 57 62

If vectors cos coti sinot jand cof B cos sin 2 the value of t at which they are orthogonal to each other is Re AIPMT 2015 1 t 0 2 t 3 t i sin are functions of time then TO 40 cof T 200 T

62 Moving An electron and a proton are revolving around common centre O in two coplanar circular paths as 2 s respectively The net magnetic field at O will be shown in figure with time period of rotation 1 s and Je 228 1 Hoe I tesla tesla e Tim 12m Hoe 2 2 4 Zero tesla

In which of the following case emf induced in the loop is maximum The orientation of identical coils and identical magnets is same in all the cases coil and magnet are in different plane OF v 2 m s OF OF mis v 3 m s 4m s 1 1 2 2 3 3 4

Two identical balls A and B having velocities of 0 5 m s and 0 3 m s respectively collide elastically in one dimension The velocities of B and A after the collision respectively will be NEET Phase 2 2016 1 0 5 m s and 0 3 m s 2 0 5 m s and 0 3 m s 3 0 3 m s and 0 5 m s 4 0 3 m s and 0 5 m s

angular acceleration a as shown in figure then Answer A B C Your Attempt Correct answer the constant magnitude of velocity of the particle in the first t sec 2a tR the angle subtended by path followed by the particle at the centre of the circle in the first t sec a t magnitude of its acceleration in the first t sec 2a R CL

In Young s double slit experiment the interference pattern is found to have an intensity ratio between bright and dark fringes as 9 What is ratio of amplitudes of interfering coherent waves 2 1 Imancon 9 ICI Te IDI HI 3 F 3 351 352 51 51 I F 51 5 SI 51 2 2 IXA

The position time graph for two particles A and I are straight lines inclined at angles of 30 and 60 with the time axis The ratio of velocities VA VE is A 1 2 C 3 1 A B C Incorrect Marked By You B 1 3 D 1 3

2 Only outside 3 Both inside and outside the rod 4 Neither inside nor outside the rod The magnetic intensity near one end of a long solenoid of length L and having N turns and carrying current i is given as 1 H Ni Ni 3 24 2L 2 MoNi 2L 4 HoNi ensional formula of magnetic inte 2 MOL 1TO

A Hollow cylinder having inner radius a and outer radius 3a is having current uniformly distributed across cross section If B Band Bo denotes magnetic field at point A B and Crespectively then 4a C 3a A B 0 B Be B 2 Hola 2na Holo 8ma

i The potential energy of a particle in a force field is where A and B are positive constants and r is the distance of particle from the centre of the field For stable equilibrium the distance of the particle is AIPMT Prelims 2012 U 1 AB 2 3 2 r A B B A B 2A 2A

Charges and Magnetism 105 Two parallel beams of electrons are produced parallel to y axis such that speeds of electrons is v If speed of light is c then ratio of electric force to the magnetic force between electron beams is 1 3 12 01 2 4 las

12 One face of a rectangular glass plate 6 cm thick is silvered An object held 8 cm infront of the unsilvered face forms an image 6 cm behind the silvered face Find the refractive index of glass Consider all the three steps 13 A lens with a focal length of 16 cm produces a sharp image of an object in two positions whi

At any instant the ratio of amount of radioactive substance is 2 1 If their half lives are respectively 12 and 16 hours then after 2 days what will be the ratio of amount of substance left 1 1 2 1 1 4

85 A population of lotus plants in a pond is 450 in the starting of January 2014 It has a birth rate of 0 2 lotus plant month The number of plants after 2 months will be a 630 c 610 b 540 d 648

Velocity of a particle moving along a straight changes parabolically with time according to the graph shown in figure Then its average velocity in the time internal t 0 to t 4 s 8 v m s 1 2 57 m s 3 6 15 m s 2 t s 4 2 4 m s 4 5 33 m s

Velocity of the ball A after collision with the ball shown in the figure is Assume perfectly inel and head on collision A 5 m s 2 m s O 2 kg B 5 kg

3 A To compensate the relativistic variation of mass at high speed of charge in cyclotron Adjustments can be made is 1 Frequency of a c is decreased 2 Magnetic field is increased 3 Peak value of a c is increased 4 Both 1 2 f length is folded to form double circula wire is i the magnetic fie

Worth While car A starts with an initial velocity of 10 m s nd an acceleration of 1 m s car B starts from rest with n acceleration of 2 m s Answer the following questions 6 As seen by a passenger in car A 1 Car B moves backward 2 First the car 8 moves backward and then forward O 3 Car B moves forward 4 First the car B moves forward and then backward 7 As seen by a passenger in car B 1 Car A moves backward 2 First the car A moves backward and then forward 3 Car A moves forward 4 First the car A moves forward and then backward The separation between the cars 1 Continuously increases 2 Continuously decreases First increases then decreases and finally increases again 4 First decreases then increases and finally decreases again Taking the moment of start as t 0 the separation between the cars at the moment t 5 s is 37 5 m with A ahead of B 2 37 5 m with B ahead of A 3 50 m with B ahead of A 4 50 m with A ahead of B The position of car A at this moment t 5 s is 1 62 5 m due North of starting point 2 37 5 m due North of starting point 3 62 5 m due South of starting point 4 37 5 m due South of starting point The position of car B at this moment t 5 s is 1 25 m due North of starting point N 4

Consider a circuit of high capacitance and very hight resistance R a battery of emf E and switch S The switch is closed at t 0 At t the heat loss through the circuit will be CE A www 20 B there will be negligible heat loss as the current in the circuit will be negligible at all instant hence i R is also negligible the heat loss in the circuit always depend upon rate of charging of capacitor A the heat loss in the circuit does not depend upon rate of charging of the capaci E

Hint 65 In the circuit shown the value of I in ampere is 492 www www 492 4 V 492 www www 492 1 6 92 www 1 1 2 0 6 3 0 4 4 1 5 Hint Total resistance of the middle branch is 6 22 and total current 1 A will b reverse ratio of resistors in the two branches

A cube of volume 1 m and specific gravity 2 is very slowly being lowered in to a lake with help of a massless string tied to one of its vertices as shown Initially the vertex B is just touching the surface of water and finally vertex A is just beneath the surface of water For the process of immersion match the columns Ignore change in KE of water g 10 ms Column 1 A Work done by gravity on water cube system B Work done by tension on the cube C Work done by gravity on water D Work done by gravity on the cube p 3 3 2 9 3 3 r 2 3 2 Column 11 x 104 Joule 10 Joule 10 Joule AT s 2 3x10 Joule t 40 3 10 Joule B