Physics Questions

The power dissipated in an AC circuit is zero if the circuit is Question Type Single Correct Type 1 Purely resistive 2 Purely inductive only 3 Either purely inductive or purely capacitive

On the superposition of two harmonic oscillations represented by X asin wt and X2 asin wt 4 a resulting oscillation with the same time period and same amplitude is obtained The value of 42 is Question Type Single Correct Type 1 120 2 90 3 60

A thin uniform ring of mass m and electric charge Q uniformly distributed rotates around an axis perpendicular to its plane and going through its center The angular momentum of the ring is 7 5 x 10 4 kg m s The ring is in a homogeneous magnetic field of a field strength of 0 1 T and the lines of the magnetic induction are parallel with the plane of the ring Torque exerted on the ring is The specific charge charge mass ratio of the ring is Q m 10 5 C kg 3 75 10 10 3 75 10 10 N m upward along the plane N m downward along the plane O 7 5 x 10 10 N m upward along the plane none of these m B

A particle of charge 1 C moving with velocity V 21 31 m s experiences a constant force F 121 81 N due to a constant magnetic field in z direction of strength x Tesla Find the value of x

One mole of an ideal gas requires 207 J heat to raise the temperature by 10 K when heated at constant pressure If the same gas is heated at constant volume to raise the temperature by 5 K then the heat required is O 62 J O O 124 J 12 4 J O 6 2 J

Q 8 A person sitting firmly over a rotating stool has his arms folded with two identical balls stretched his arms along with balls and then the work done by him Answer A zero B Your Attempt C positive negative Correct answer Rate this

53 A cube of edge length 10 cm is just balanced at the interface of two liquids A and B as shown in figure If A and B has specific gravity 0 6 and 0 4 respectively then mass of cube is 1 240 g 6cm ETN 14cm TINAN 2 360 g

A student holds a laser that emits light of wavelength 633 nm The beam passes though a pair of slits separated by 0 300 mm in a glass plate attached to the front of the laser The beam then falls perpendicularly on a screen creating an interference pattern on it The student begins to walk directly toward the screen at 3 00 m s The central maximum on the screen is stationary Find the speed of the first order maxima on the screen

There are four elements P Q R and S their configuration are also given Which element will have highest value of I P II Question Type Single Correct Type 1 2 3 4 P He 2s Q He 2s 2p R He 2s 2p S He 2s 2p

In the given diagram with what force must the man pull the rope to hold the plank in position Weight of the man is 60 kg Neglect the weights of plank rope and pulley Question Type Single Correct Type 1 2 3 4 150 N 300 N 600 N 120 N

The equation of a simple harmonic wave is given by y 3 sin 50 t x 2 where x and y are in metres and t is in seconds The ratio of maximum particle velocity to the wave velocity is Question Type Single Correct Type 1 2 3 2 WIN 3 3 2

A rigid container has a hole in its wall When some air is filled in it at 27 C weight of air in it is 100 gm Now the temperature of air inside is increased by AT the weight of air becomes 50 gm AT should be 27 C C O 300 C 327 C

When illuminated four equally spaced parallel slits act as multiple coherent sources each differing in phase from the adjacent one by an angle Use a phasor diagram to determine the smallest value of o for which the resultant of the four waves assumed to be of equal amplitude is zero

The electric fields from three coherent sources are described by E Eo sin wt Eo sin wt E2 Eo sin wt and E3 Eo sin wt 20 Let the resultant field be repre sented by Ep ER sin wt a Use phasors to find ER and a when a 20 0 b 60 0 and c 120 d Repeat when 3 2 rad d

Suppose the slit openings in a Young s double slit experi ment have different sizes so that the electric fields and intensities from each slit are different With E1 E01 sin wt and E2 E02 sin wt d show that the resultant electric field is E Eo sin wt 0 where Eo E E2 2E01E02 cos and For sin d

Use phasors to find the resultant magnitude and phase angle of two fields represented by E 12 sin wt and E2 18 sin wt 60 Note that in this case the ampli tudes of the two fields are unequal

Five capacitors of 10 F capacity each are connected to a DC potential of 100 volts as shown in figure The equivalent capacitance between the points A and B will be equal to 10 F 10 F 10 F 140 F 10 F 100V B 10 F Question Type Single Correct Type

4 The phase difference between the two given waves is Y a sin ot 2 1 2 Y a cos ot 3 0 2 2 a X 2 x 4 2 4 Q 23 CST 6 PN Junction Diode TU 2

The two speakers of a boom box are 35 0 cm apart A single oscillator makes the speakers vibrate in phase at a frequency of 2 00 kHz At what angles measured from the perpen dicular bisector of the line joining the speakers would a distant observer hear maximum sound intensity Minimum sound intensity Take the speed of sound as 340 m s

A uniform wire of mass 3m and length 31 is bent into the shape of an equilateral triangle and suspended from a horizontal axis X X in a vertical plane as shown A uniform vertical upward magnetic field B is existing in the region If charge Q is passed almost instantaneously through the triangular loop then the angular velocity acquired by the triangular loop immediately after charge passed is A C 3BQ 5m 3 3BQ 5m B D 2 3BQ 5m 4 3BQ 5m B B m B m m

For toroid of mean radius 20 cm turns 240 and a current of 2A What is the value of magnetic field within toroid Question Type Single Correct Type 14 8 10 4 T 2 2 4 x 10 4 T 3 1 2 10 4 T

Two narrow parallel slits separated by 0 250 mm are illuminated by green light 546 1 nm The interfer ence pattern is observed on a screen 1 20 m away from the plane of the slits Calculate the distance a from the central maximum to the first bright region on either side of the central maximum and b between the first and second dark bands

J 2 5 1 XBX A conducting wire frame is placed in a magnetic field which is directed into the paper The magnetic field is increasing at a constant rate The directions of induced current in wires AB and CD are X X X X Cx B to A and D to C M 2 A to B and C to D Dx Question Type Single Correct Type 3 A to B and D to C 5 X X 2 2

The intensity on the screen at a certain point in a double slit interference pattern is 64 0 of the maximum value a What minimum phase difference in radians between sources produces this result b Express this phase differ ence as a path difference for 486 1 nm light

The ammeter reading in the following circuit will be 69 202 wwwwww 65 wwwww 692 Question Type Single Correct Type 1 1 8 A 2V 3 24 A

Projection of a Particle in a Potential Field Potential energy of a particle of mass m k depends on distance y from line AB according to relation U y a where k is a positive constant A particle of mass mis projected from y 3 a toward point O on line A AB Find the minimum projection speed of particle so that it will cross point O 14 Pam O E

A current flowing through the inductor of inductance L has a shape indicated in Fig The highest value of current is lo What will be the maximum voltage drop across the inductor O O zero 2T Llo 2T lo 0

In terms of light red light is emitted when an electron a hits into the photon and is absorbed b crosses the bandgap to a lower energy state and emits a photon c Emits a proton d moves to a higher orbital across the bandgap e emits a phonon

Inside a uniformly charged infinitely long cylinder of radius R and volume charge density p there is a spherical cavity of radius R 2 A point P is located at a distance 2R from the axis of the cylinder as shown Then the electric field strength at the point P is A C 23pR 54 25pR 54 B D 23pR 108 25pR 108 R R 2 R 2 2R

In a location where the speed of sound is 354 m s a 2000 Hz sound wave impinges on two slits 30 0 cm apart a At what angle is the first maximum located b What If If the sound wave is replaced by 3 00 cm microwaves what slit separation gives the same angle for the first maximum c What If If the slit separation is 1 00 um what frequency of light gives the same first maximum angle

Steel ruptures when a shear of 3 5 x 108 Nm 2 is applied The force needed to punch a 1 cm diameter hole in a steel sheet 0 3 cm thick is nearly Question Type Single Correct Type 1 2 3 4 3 3 104 N 1 4 104 N 1 1 104 N 2 7 x 104 N

A four stroke CI engine having a cylinder diameter of 39 cm and stroke of 28 cm has a mechanical efficiency of 80 Assume the frictional power to be 80 kW Its fuel consumption is 86 kg h with an air fuel ratio of 18 1 The speed of the engine is 2000 rpm Calculate i indicated power ii if nith is 40 calculate the calorific value of the fuel used iii Pim iv ma hour v Sp

In a double slit arrangement of Figure 37 5 d 0 150 mm L 140 cm 643 nm and y A 1 80 cm a What is the path difference 8 for the rays from the two slits arriving at P b Express this path difference in terms of A c Does P correspond to a maximum a minimum or an interme diate condition

A charged particle q of mass m is placed at a distance d from another charged particle 2q of mass 2m in a uniform magnetic field B as shown in figure If the particle are projected towards each other with equal speed of 2Vm where Vm is the maximum value for which the two particles do not collide then the time after which collision occurs between the particles is found to be nm where value of n is qB q m 2Vm 2Vm d 2q 2m

18 A uniform cylindrical rod of length L cross section and Young s modulus Y is acted upon by the forces as shown in figure The elongation of the rod is 1 3 3F 2 F 5 AY 3 F 2 F co r 3 F 5 AY 8 F 2F roid

resistor and a length all are A 2 volt battery a 15 potentiometer of 100 cm connected in series If the resistance of potentiometer wire is 5 0 then the potential gradient of the potentiometer wire is Question Type Single Correct Type 1 0 005 V cm 2 0 05 V cm 3 0 02 V cm

1 The diagram shows a student standing midway between a bell tower and a steep mountainside bell tower and bell 000 990 m student 990 m steep mountainside The bell rings once but the student hears two rings separated by a short time interval a Explain why the student hears two rings 2 b State which of the sounds is louder and why 2 c Sound in that region travels at 330 m s i Calculate the time interval between the bell ringing and the student hearing it for the first time ii Calculate the time interval between the bell ringing and the student hearing it for the second time iii Calculate the time interval between the two sounds 2 1

42 teur 1 r 1 Fort 201 Loter K 2 3 A uniform magnetic field of indu confined to a cyclindrical region of radius R The magnetic field is increasing at a constant dB dt rate of tesla second An electron e m placed at the point P on the periphery of the field experiences an acceleration 4 0 CIER leR dB 2m dt leR dB 2m dt eR dB m dt X X X X X X x R X xx x X X X X P X towards left towards left X towards right X X X xx X E R I

A solenoid having a core of 10 3 m in cross section half air u 1 and half iron 500 is 1m long the no of turns are 2000 What is coefficient of self induction 0 5H 0 75 H 1 26 H 2 25 H moo 1 2m 1 2m

31 32 33 34 As shown in figure a convergent lens is placed inside a cell filled with liquid The lens has focal length 20 cm when in air and its material has refractive index 1 50 If the liquid has refractive index 1 60 the focal length of the system is 25 26 Question Type Single Correct Type 1 2 80 cm 28 29 30 80 cm

In the circuit shown the switch S is closed at t 0 The capacitor is initially uncharged Then the current through the resistor R 802 at t 0 4 x 103 sec is Take e 0 135 A 0 18 A B 0 27 A C 0 54 A D 0 72 A R 80 www S 40 201 HH m

In the adjacent circuit the capacitor A of capacitance 3C and the capacitor B of capacitance C are initially charged by potential drops 4 and 8 respectively and connected through an inductor of inductance L with zero initial current as shown The switch S is closed at t 0 then the maximum current through the inductor is 3C A B C D 6C L 12C L 15C L eeeeeee 12 Ce A 8 Ce B 3C C 12 Ce 8 Cs

4 In an optics lesson a Physics student traces the paths of three rays of light near the boundary between medium A and air The student uses a protractor to measure the various angles The diagrams below illustrate the three measurements ray 3 ray 1 Antalet Intii ray 2 I 180 30 20 10 T 0SL OPL 0EL OZL OLL OOL 08 07 09 09 04 08 0 10 160 170 091 OPL EL OZL OLL COL 06 0 or 09 09 04 08 001 01L OZL OEL OFL OSL 08 OL 30 06 DSL OFL OEL OZL OLL OOK 0 09 09 0 08 09 06 09 04 08 09 09 09 40 09 90170 160 150 40 90 170 160 150 140 30 40 180 170 00L OLL OZL OEL OPL 09 091 OL 08 30 0 10 20 30 10 20 mod m air medium A air medium A air medium A a State which is the optically denser medium A or air and how you can tell this 1

The modulation frequency of an AM radio station is 250 kHz which is 10 of the carrier wave If another AM station approaches you for license what broadcas frequency will you allot 1 2750 kHz 3 2250 kHz 2 2900 kHz 4 2000 kHz

a series ac circuit the instantaneous voltage e t and current i t are given b 5 cos wt 3 sin wt 5 sin wt 7 amp Then circuit is in resonance circuit is Inductive circuit is capacitive Information insufficient

A mixture of 2 moles of helium gas atomic mass 4 amu and 1 mole of argon gas atomic mass 40 amu is kept at 300 K in a container The ratio of the Vrms helium rms speeds Vrms argon is Question Type Single Correct Type 1 2 3 0 32 0 45 2 24

o Negative Marks 1 If wrong option is selected A vessel with open mouth contains air at 60 C When the vessel is heated upto temperature T one fourth of the air goes out The value of Tis O 80 C 171 C 333 C

XM Two circular coils X and Y have equal number of turns and carry equal currents in the same sence and subtend same solid angle at point O If the smaller coil X is midway between 0 and Y then if we represent the magnetic induction due to bigger coil Y at O as By and that due to smaller coil X at O as Bx then Y 1 3 By Bx By Bx 1 d X 2 4 BY Bx By Bx 2 4 ALLEN O 38

Q No 13 While measuring the surface tension of a liquid by a capillary of non uniform bore its radius should be measured 1 at the lower end dipped in liquid at the upper end open in air 3 by taking mean of the radii at the two ends by cutting the capillary at the point up to which the liquid rises in the capillary Correct Answer 4 Status unattempted

An amplitude modulated signal is given by V t 10 1 0 3 cos 2 2 x 1041 sin 5 5 x 105t Here t is in seconds The sideband frequencies in kHz are Given n 22 7 1 1785 and 1715 2 178 5 and 171 5 3 89 25 and 85 75 4 892 5 and 857 5