Physics Questions

A disc is placed on the surface of pond with liquid of 5 refractive index A source of light is placed 4 m below the 3 surface What is minimum area of the disc so that light does not come out of liquid 28 26 m 42 4 m 32 62 m 32 6 m

A sample of radioactive element has a masss of 10 g at an instant t 0 The approximate mass of this element in the sample after two mean lives is a 2 50 g b 3 70 g c 6 30 g d 1 35 g

An object of mass 500g initially at rest is acted upon by a variable force whose X component varies with x in the manner shown The velocities of the object at point X 8 m and X 12 m would be the respective values of nearly F N 20 10 10 20 25 77 458 10 12 1 18 m s and 24 4 m s 2 23 m s and 24 4 m s 3 23 m s and 20 6 m s 4 18 m s and 20 6 m s x m

A ball with a speed of 9 m s collides with another identical ball at rest Afte the collision the direction of each ball makes an angle of 30 with the original direction The ratio of velocities of the balls after collision is x y where x is Answer

When an incandescent electric bulb glows A the electric energy is completely converted into light energy B the electric energy is partly converted into light energy and partly into heat energy C the light energy is converted into electric energy D the electric energy is converted into magnetic energy

The moment of inertia of a uniform thin rod about its perpendicular bisector is I If the temperature of the rod is increased by At the moment of inertia about perpendicular bisector increases by coefficient of linear expansion of material of the rod is a a Zero b la st c 2 la At d 3la At

5 A force acts on a 2 kg object so that its position is given as a function of time as x 31 5 What is the work done by this force in first 5 seconds a 850J b 950 J c 875 J d 900 J LIFF Main

A particle of mass m is executing simple harmonic motion about its mean position If A is the amplitude and T is the period of S H M then the total energy of the particle is A B C D 4 m T 8 m T 2 m T m

A uniform electric field of 100 N C exists in XY plane making an angle 60 with x direction Consider points A 1 2 3 m and B 3 2 1 m then V V is 1 100 volt 2 200 3 volt 3 283 volt 4 400 volt A B

Match the corresponding entries of Column 1 with Column 11 Where m is the magnification produced by the mirror Column 1 A m 2 1 2 C m 2 B m 1 D m 2 Column II p Convex mirror C q Concave mirror r Real image Virtual image a A p and s B q and r C q and s D q and r b A r and s B q and s C q and r D p and s c A q and r B q and r C q and s D p and s d A p and r B p and s C p and q D r and s S

A simple harmonic progressive wave is represented as Y A sin 2 t nt c cm It the maximum particle velocity is four times the wave velocity then the wavelength of the wave is A B TT A 4 4 A C 2 TA D TT A 2

For a short period of time the frictional driving force acting on the wheels of the 2 6 Mg van is I 6002 N where is in seconds Figure 1 igure V 1 of 1 Part A If the van has a speed of 18 km h when 0 determine its speed when 5 s Express your answer to three significant figures and include the appropriate units v 4 99 Submit m S Previous Answers Request Answer Incorrect Try Again 4 attempts remaining

35 A R 1502 www R 1002 www R 300 wwwww Find the resistance across AB R 2002 www B

A spinning ball is moving in a direction opposite to the direction of the wind The ball moves in a curved path as a the pressure at the top and the bottom of the ball are equal b the pressure at the top the pressure at the bottom c the pressure at the top the pressure at the bottom d there is no relation between the pressures

17 Two uniform rods of mass m and length I form a cross moment of inertia of cross about an axis parallel to CD passing through A is ml 3 Sol Answer 2 1 2 7m 12 A 10 D B 12 D

The current in the given ciruit is 4 8 VT R 302 ww R 60 1 1 6 A 2 2 A 3 0 32 A 4 3 2 A Hint R R are in series and then R in parallel I VIR eq not be considered R 6n

Two particles are in SHM in a straight line Amplitude A and time period T of both the particles are equal At time t 0 one particle is at displacement Y A and the other at Y A 2 and they are approaching towards each other After what time they cross each other 1 T 3 3 5T 6 2 T 4 4 T 6

S and S are two slits in horizontal fixed plane on which light of wavelength 6000 A is incident d 1 mm D 1 0 m O is the origin of the coordinate system At t 0 the screen is released g 10m s Se Sv fer af en af d 1 mm D 1 0 m g 10m s Find the velocity of central maxima at t 4 sec 4 sec 1 40 m s D R6000 D 1 2gt 2 80 m s S 3 40 2 m s v gt Mo y S 6000 M 4 80 2 m s

The length of a metal wire is when the tension in it is F and when the tension becomes F Find the natural length of wire L F F 2 2 a F F c L F F F F b d 4 F F F F 21 G F C F F F

A particle is projected with velocity vo along x axis A damping force is acting on the particle which is proportional to the square of the distance from the origin i e ma ax The distance at which the particle stops 3 H A B 200 3x 3v 2a 3 2 D

ing square loop of side L and resistance R moves in its plane with a uniform velocity v perpendicular to one of its sides A magnetic induction B constant in time and space pointing perpendicular and into the plane at the loop exists everywhere with half the loop outside the field as shown in figure The induced emf is a zero d v BL b RvB c vBL R 113

as shown in figure the distance travelled by the car in the 25s is A 750 m B 875 m C 500 m D 975 m The acceleration of a car started at 1 0 varies with time as shown in figure the distance travelled by the car in the 25 vis Aj 750 m B 875 m C 500 m D 975 m

16 An 80 6 nucleus is spherical having radius R surface area A and volume V According to empirical observations the volume of the so Sn 28 nucleus assumed to be spherical is V radius R and surface area A Then A R 8R C V 8V B A 8A D R 2R

An R C series circuit is charged in two ways In first case it is connected to the terminals of a cell of emf 2E In second case it is connected to the terminals of a cell of emf E After getting fully charged with E it is connected to cell of emf 2E and charged till saturation In second case as compared to first case P List I Saturation charge on capacitor Maximum energy stored in capacitor 2 R Energy supplied by cell s 3 S Heat generated in resistor 4 List II Increases if the cells are ideal Decreases if the cells are ideal Remains same if the cells are ideal Data is incomplete to predict formation

A parallel circuit consists of the two ideal inductances L and 2L and a resistance R as shown At t 0 the same current 101 is flowing in both the inductances in the same direction Then choose the correct option s LI A The energy stored in inductance L in steady state is 18 B The energy stored inductance 2L in steady state is zero C The net heat dissipated in the resistor is 3L13 2 4 The net heat dissipated in the resistor is L 3 L eeeeeee 21 0000000 93 dii Jd at e

A particle moves in a straight line and its position x at time t is given by x 2 t Its acceleration is given by 2 1 X 3 1 1 4x 2 1 4 2

26 A uniform wire of mass M length L area of cross section A and Young s modulus Y is suspende from the ceiling Elongation of the wire due to its own weight is 1 3 MgL 2AY MgL 2V 2 4 MgL 2AY MgL3 2AY

A particle performs S H M from the mean position Its amplitude is A and total 3E energy is E At a perticular instant its kinetic energy is The displacement of the 4 particle at that instant is A B C D A AL8 A 4 D A

he figure below shows the schematic for a mass spectrometer which consists of a velocity selector and a deflection chamber The magnitude of the magnetic field in both the velocity selector and the deflection chamber is 0 0610 T and e electric field between the plates of the velocity selector is 3100 V m If a singly charged ion with a mass of 1 34 x 10 26 kg travels through the velocity selector and into the deflection chamber determine the radius of its trajectory in e deflection chamber x Enter a number article travels straight through a velocity selector how is the force acting on the particle by the electric field related to the force acting on the particle by the magnetic field How is the speed of the moving charged particle elated to the magnitude of the electric and magnetic field What type trajectory does a particle move in when it experiences a force perpendicular to its motion What provides the centripetal force for the ion as it travels in the deflection hamber m B

cylindrical region of radius 10 cm as shown in figure A uniform wire of length 80 cm and resistance 4 0 2 is bent into a square frame and is placed with one side along a diameter of the cylindrical region If the magnetic field increases at a constant rate of 0 010 T s find the current induced in the frame a X X 1 3 9 105 A 2 0 2 x 105 A 3 08 10 5 A 4 10 x 105 A Xx X X X X X X X X b X X d

A squirrel of mass m climbs slowly on a thin straight vertical rod of length L Mass of the rod is negligible as compared to that of the squirrel and size of the squirrel is negligible as compared to the length I that it climbs on the rod Due to weight of the squirrel the rod bends at its lower end through an angle and due to elasticity of the material of the rod a restoring torque CO is developed If C 2mgl find the maximum length the squirrel can climb on the rod a L 2 c L b 3L 4 d 2L

A coil having n turns and resistance R2 is connected with a galvanometer of resistance 4RG combination is moved in time t seconds from a magnetic flux weber to weber The current in the circuit is a 5 Rnt b n 6 6 SP c d n 6 6

A fully charged capacitor C with intial charge qo is connected to a coil of self inductance L at t 0 The time at which the energy is stored equally between the electric and the magnetic fields is 1 2T LC 2 VLC 3 TV LC 4 TU VLC

Two polarising sheets are placed with their plane parallel so that light intensity of transmitted light is maximum Through what angle must either sheet be turned so that light intensity drops to half of maximum value 30 45 135 Both 2 and 3 are correct

3 2 Find the distance between the images formed by the concave mirror due to this light In Fig 1 372 L is a converging lens of focal length 10 cm and M is a concave mirror of radius of curvature 20 cm A point object O is placed in front of the lens at a distance of 15 cm AB and CD are optical axes of the lens and mirror respectively Find the distance of the final image formed by this system from the optical center of the lens The distance between CD and AB is 1 cm L A O 15 cm C 45 cm D 1 cm B

Find out the value of T in the given diagram 1 12 N 37 2 8 N 3 6 N 4 3 N 35 37 1 12 N 2 8 N 3 6 N

The speed of sound in oxygen is 315 ms At the same temperature its speed in a mixture of oxygen and nitrogen in the ratio 1 4 by volume is given 10 3 162 1 320 ms 1 1 3 332 ms 2 310 ms 1 4 340 ms 1

At resonance in a series LCR circuit which of the following statements is true 1 Current in the circuit is maximum and phase difference between E and I is 2 2 Current in the circuit is maximum and phase difference between E and I is zero 3 Voltage is maximum and phase difference between E and I is 2 4 Current is minimum and phase difference between E and I is zero

A coil has an area of 0 05 m and it has 800 turns It is placed perpendicularly in a magnetic field of strength 4 x 105Wb m it is rotated through 90 in 0 1 second The average emf induced in the coil is 1 0 056 V 2 0 046 V 3 0 026 V I

A sample of hydrogen atoms de excites from 6th excited state to the ground state in one or more electronic transitions If no spectral line is obtained in the Paschen and Brackett series then the maximum number of spectral lines of different photon energies obtained will be Question Type Single Correct Type 1 21 2 15 2 10

A tangent galvanometer has a coil of 25 turns and a radius of 15 cm The horizontal component of the earth s magnetic field is 3 10 T The current required to produce a deflection of 45 in it is 2 1 2 A 1 0 29 A 3 3 6 10 A 4 014 A

44 Potential difference across AB in the network shown in figure is 1 2 V 2 3 V 3 1 V 4 1 5 V ww 30 92 www 30 92 B 1592 www 3 V 50 Tower 8 Pusa Road New Delhi 110005 Ph 011 47

7 1 50 N 2 25 N 3 500 N 4 10 N Three blocks with masses m 2m and 3m are connected by strings as shown in the figure After an upward force F is applied on block m the masses move upward at constant speed v What is the net force on the block of mass 2m g is the acceleration due to gravity 1 Zero 2 2 mg 3 3 mg 4 6 mg AF m 2m 3m T 27 1 50 N 2 25 N 3 dia i fanger va BRI E T m 2m 3m m 3 3 fanda Torta calu 1 Zero 2 2 mg 3 3 mg 4 6 mg Gia Er 2n F m 2m 3m

Illustration 3 6 A plate of mass 10 g is in in air due to the force exerted by equilibrium a light beam on the plate Calculate power of the beam Assume that the plate is perfectly absorbing 111 Fig 3 8

5 A particle of mass m 1 kg is lying at rest on x axis experiences a net force given by I F x 3x 2 Newton where x is the x coordinate of the particle in meters The magnitude of minim velocity in negative x direction to be imparted to the particle placed at x 4 meters such that it read P P V27 m s Find the value of 1300 the origin is

A coil of inductance 50 H and resistance 0 5 2 is connected to a battery of emf 5 V A resistance of 10 2 is connected parallel to the coil Now at some instant the connection of the battery is switched off Then the amount of heat generated in the coil after switching off the battery is 1 1 25 mJ 2 2 5 mJ 3 0 65 mJ

9 Two capillary tubes A and B are immersed in water One is straight and the other is in the form of a rectangular U tube as shown in figure The tube A is sufficiently long The lower end of the bent tube is at depth H Then there will be no flow of water from tube B is P 2 2 1 H h 3 H 0 A B H 2 0 H h 4 All of these

10 Find the effective resistance between points A and B BREDBE www 19 10 192 wwww 192 1 3 1 C L wwww 192 192 www www 192 192 wwww 1 2 A www www 12 122 LM www B 192 wwww www 192 19 www 12 2 3 1 1 3 3 1 www 19 aas

An electric field applied along the length of a long cylinder produces a polarization P The depolarization field produced in this configuration is a 4 P 3 b 4 P 3 WAT c 2 P d 0 the following Manuell s equations implies the absence of magnetic monopoles

Two heater wires of same length are first connected in series and then in parallel The ratio of the amounts of heat produced in two cases will be 2 1 4 4 1 2 AJOR SRG ACU ALL ENTHUSE LEADED COU 1 4 1 3 2 1 SEPTEM