Basic Physics Questions and Answers

in For the concerned thin spherical shell E Therefore equation iv becomes inside U4 2 2 E dv space U 4 2 E ov U outside v To find the value of the integral let us take a hypothetical shell of radius R and thickness dr Therefore the volume of the hypothetical shell is dV 4dr By substituting this value in equation v we get 30 U I U U 20 n 20 2014 ATE outside l 4 outside L 4mrdr 2 48 ATE 2R Anr dr 2 4 r 10 ow can volume of spherical shell be 4 pi r

0 Temperature of a body is slightly more than the temperature of the surrounding its rate of cooling R versus temperature of body 0 is plotted its shape would be as per Newton s law 1 3 R RA 0 2 RA

part of a wooden piece sinks in water and the 4 3 remaining part of it sinks in another liquid The 4 density of the liquid will be A 3 g cm C 12 g cm B D 1 4 g cm 1 3 g cm

When a conducting wire is connected in the left gap and known resistance in the right gap the balance length is 75cm If the wire is cut into 3 equal parts and one part isconnected in the left gap the balance length 1 shifts left by 25cms 3 shifts left by 50cms 2 shifts right by 25cms 4 shifts right by 50cms

In the arrangement shown below S is the source of light of wavelength If A Tef a Gaucher chi zata A D d l There is minima at O then minimum XD 2 value of dis D Ad dc Yado M3 Correct Answer B value of dis XD There is minima at O then minimum Add y 13 XD V Your Answer C value of dis 2XD There is maxima at O then minimum 1 Your Answer 2XD D value of dis AD V 038 D There is maxima at O then minimum

14 Two identical positive charges are placed on the y axis at y a and y a The variation of electric potential Valong x axis is shown by graph V a c b V

Find electric field at point P which is situated at r distance from centre perpendicular to plane of hexagon r a Question Type Single Correct Type 1 2 4kQa r3 a zero

A man standing in front of a mountain beats a drum at regular intervals The drumming rate is gradually increased and he finds that echo is not heard distinctly when the rate becomes 40 per minute He then moves near to the mountain by 90 metres and finds that echo is again not heard distinctly when the drumming rate becomes 60 per minute Calculate a the distance between the mountain and the initial position of the man and b the velocity of sound

1 Resolve the force F into two components acting along the u and v axes and determine the magnitudes of the components 75 30 30 F 4 1676

smooth horizontal track Find the ratio where a is acceleration of point A and a is angular acceleration of rod just 2a la after release 2 Just vertical mun 60 609 massless string l 60 B uniform rod

4 Doppler effect in sound is asymmetric and in light is symmetric At t 0 a transverse wave pulse travelling along positive x direction with speed 3 m s in a string 9 described by the function ya given that X x 0 Transverse velocity of particle at x 3 m and t 3 s will be 2 m s 4 m s 1 m s 4 3 m s

A radio station broadcasting at a frequency of 1500kHz gerertes a directional beam by using an array of 4 point ource antennas driver in phase with each other by the same transmitter The antennas are arranged along an east west line so tha each antenna is 50m from the next one 50 m 2 a In what direction will be radiated signal to greatest b How mcuh signal radiates in east west direction

3 15 cm 4 25 cm A spherical shell of mass m and radius R is pulled on a horizontal plane by a horizontal force F acting on its centre of mass If shell is rolling without slipping then angular acceleration of the spherical shell will be 1 3 3F 2mR 5F 7mR 2 4 3F 5mR 5F 2mR

A spring 40 mm long is stretched by the application of a force If 10 N force required to stretch the spring through 1 mm then work done in stretching the spring through 40 mm is 1 84J 2 68J 3 23J 4 8J

2 The coil of moving coil galvanometer is swinging periodically To bring it to rest we have to 1 Connect a very small resistance in parallel 2 Connect a small resistance in series 3 Earth the galvanometer case 4 Bring an aluminium pjece near it

Choose the correct answer 1 The mass and volume of a body are 6 237 g and 3 5 cm respectively The density of the material of the body in correct significant figures is 1 1 78 g cm 3 1 8 g cm 2 1 782 g cm 4 1 7 g cm

44 The length of a metal wire is when the tension in it is T and 12 when the tension in it is T2 The unstretched length of the wire is 2 1 3 T l Til T T T T T T T l T T T T T T T

Two concentric hollow spheres of radii R and 2R are charged The inner sphere has a charge of 1 C and the outer sphere has a charge of 2 C of the same sign The potential is 9000 V at a point P at a distance 3R from the common centre O What is the value of R

Arrange red light blue light green light and yellow light in increasing order of resolving power 1 Red Green Blue Yellow 2 Red Blue Yellow Green 3 Blue Yellow Green Red 4 Red Yellow Green Blue

At t E 0 a source of sonic oscillations S and on observer O start moving along x and y axes with 5m s and 10m s The figure shows their positions at t 0 If frequency of source is 1000Hz Find the frequency of singals received after 5 second sound 330m sec S 100 m YA 100 m X

Three point charges q 2q and q are placed at points x 0 y a z 0 x 0 y 0 z 0 and x a y 0 z 0 respectively The magnitude and direction of the electric dipole moment vector of this charge assembly are 1 2qa along x direction 2 2 qa along y direction 3 2 qa along the line joining points x 0 y 0 z 0 and x a y a z 0 4 qa along the line joining points x 0 v 02 0 and f E02 BOAI BO TARGET PHYVENGMODULE 04 1 ELECTROSTATICS 02 FX FRO

Two immiscible liquid are filled in conical flask as shown in figure The area of cross section is shown a small hole of area a is made in lower end of cone Find speed of liquid flow from hole A C 1 2gh 17a A 2gh 17a 32A B D 1 gh 17a A 3gh 1 17a 32A h h Open to air 2p A

The position of a particle at time t is given by an equation x 1 e Vo is constant and A 1 6 A 0 The dimensions of Vo and A respectively are x 1 MOLT 1 MOLT 2 3 M L T M LT 2 MOLT 1 MOLOT 1 4 MOLT 1 MOLOT 2

A fork lift truck lifts a heavy box onto a shelf Which action requires the greates t power output from the fork lift truck Lifting the box from the ground to the h igh shelf slowly Lifting the box from the ground to the h igh shelf quickly Lifting the box from the low shelf to the high shelf quickly Lifting the box from the low shelf to the high shelf slowly

ins same 4 nothing can be said A stone of mass 4kg is whirled in a horizontal circle o radius Im and makes 2 rev sec The moment of inerti of the stone about the axis of rotation is 1 64 kg x m Y 4 kg m 3 16 kg x m 4 1 kg m Three rings each of mass P and radius Q are arrang as shown in the figure The moment of inertia of arrangement about YY axis will be 1 PQ 2 2 PQ 3 PQ 5 4 PQ 2 MR2 99 P P Spac I 4x1 4 Icom 21 I

Where all the symbols have their usual meanings and are in SI units The speed of the wave is 1 32 m s 2 64 m s 3 20 m s 4 15 m s

The dip at a place is 8 For measuring it the axis of the dip needle is perpendicular to the magnetic meridian If the axis of the dip needle makes angle 0 with the magnetic meridian the apparent dip will be given by tan 8 which is equal to 1 tan 8 cos 0 2 tan 8 sec 0 3 tan 8 sin 0 4 tan 8 cosec 0

Tas st ace charge density o nis the unit vector in outward norma direction A tiny hole is cut into its surface Ther the electric field just outside hole is 1 Zero 2 O o O

5 Rohan is running down with some acceleration on a plank kept on fixed inclined plane as shown in figure Which of the following cases are possible 1 Plank may accelerate up 2 Plank may accelerate down 3 Plank may be at rest 4 All of these

The equivalent capacitance between point A and B as shown in the figure is Co is capacitance of each capacitors in air A 4KCo 31KC00 3 00 K 3K B

1 A U shape vessel shown consists of two cylindrical vertical arms A and B of cross sectional area SA 300 cm and SB 500 cm A very light piston can slide without friction in the arm A and confines water below it A thin light thread attached to the piston at one of its ends passes under two ideal pulleys fixed at the bottom of the vessel and then attached at the other end to the bottom of a very light cube C of side 1 10 cm Initially when a block of mass m is placed on the piston the cube floats with negligible portion inside the water and the thread is not slack How high will the piston move if the block is gradually lifted off the piston Density of water is po 1000 kg m BL

Assume end correction approximately equals to 0 3 x diameter of tube estimate the approximate number of molesc present inside the tube Assume tube is at NTP and at NTP 22 4 litre contains 1 mole

3 4 x 10 rad 4 5 x 10 rad 8 When a hydrogen atom initially at rest emits a photon resulting in transition from n 6 to n 1 its recoil speed will be mass of proton 1 6 x 10 7kg 1 5 m s 3 10 m s 2 2 m s 4 4 4 m s

7 The velocity time and acceleration time graph o a particle are given Velocity Time Time Its position time graph may be given as 1 3 Position uogiso Acceleration Time 2 4 Position sition Time

A rigid wire carrying current i consists of a semi circular portion of radius R and two straight sections The wire is immersed in perpendicular magnetic field Bo The magnetic force on the wire is X X X XX X X X X X X X X X X X x X X X X X X X X X X X x TURBO 2iRBO iRBO

A body is projected vertically up with certain velocity At point P in its path the ratio of its potential energy to kinetic energy is 36 64 The ratio of velocity of projection to velocity at P is 3 54 914 The radiue of quration 2 4 413 3 2 body about on oxic

Q 6 MULTIPLE CHOICE A capacitor is charged to a potential difference of 100 V and then it is connected across a resistor After one second the potential drop across the plates of the capacitor becomes 80 V Then 100 v ac fa c 3 yg ufaduc Auz au d 21 Ch Aug H m auka h 80 A heat in first 2 second is Fraction of field energy converted into 369 625 uga 2 ug 7 304 Gyaka a Guf c HI 369 625 B After 2 second potential difference between the plates of the capacitor will become 60 V 2 Fuka A AA F 60 V Correct Answer C volts after 2 second 2 7cU5 al HIR U 3d I 64 c Giai Correct Answer is T Charge on the capacitor becomes 64 D Time constant of this discharging circuit second

Q 7 MULTIPLE CHOICE When the terminals of a cell of emf 1 5 V are connected to an ammeter of resistance 40 the ammeter reads 0 3 A Which of the following statements is are correct 1 5 V gaff A ucz f a fuga a ich 0 3 A H AH GYA I The cell is non ideal Correct Answer Your Answer B If a 4 Q resistor is also connected across the terminals of the cell the ammeter will read 0 5 A 40 f ug h da h zfad Ad a ad coch 0 5 A C If a 4 Q resistor is also connected across the terminals of the cell one third of the electrical power generated will dissipate as heat in the cell fa ug t da fad AJ a a 3 ay 40 za fu R fag 304 24 a Correct Answer D If a voltmeter of resistance 4 Q is used to measure potential difference between terminals of the isolated cell it will read 1 2 V uf 40 ufaktu ych atcc fice ci 34u fa na feq fayade H47 CR7 fag

A student measured the length of a rod and wrote it as 2 30 cm Which instrument did he use to measure it 1 A meter scale 2 A screw gauge having 50 divisions in circular scale and pitch as 1 mm 3 A Vernier calliper where 10 divisions in Vernier scale matches with 9 divisions in main scale and main scale has 10 divisions in 1 cm 4 A screw gauge having 100 divisions in circular scale and pitch as 1 mm

particle varies with AIEEE 2006 arteg od eq 0 1 nadw X At a time t in motion 163 A block slides down a smooth inclined plane of inclination 0 with the horizontal in time t Another block Soms falls freely from the same point to the ground in time 2003 t 2 The value of 0 is

3 If separation between a source and a detector changes due to relative motion between them the detector detects sound of pitch different from that emitted by the source This observed change in pitch is known as Doppler s shift and the effect is known as Doppler s effect Under the conditions when Doppler s shift is observed intensity of the sound also changes In this task we study change in intensity of sound detected by a detector due to relative motion between a source and a detector A point source is emitting sound isotropically at constant power P and the sound travels with velocity c relative to the air a A detector is moving with a constant velocity v towards a stationary source in still air Find suitable expression for intensity I of sound received by the detector at a distance r from the source b A point source is moving with a constant veloci owards a stationary detector in still air Find suitable expression for intensity I of sound received by the detector at a distance r from the source

26 A particle is moving on a circular path of radius R with uniform speed u The displacement of the particle when the radius vector rotates by an angle 30 is 1 R 3 2Rsin 15 3 2 4 Rsin 15

End to End connection in single mode fiber is Option 1 some time easy and some time difficult Option 2 very easy Option 3 easy Option 4 Difficult

The radius of gyration of a body about an axis parallel to axis passing through centre of mass and at a distance 7 cm from centre of mass is 2 9 cm 4 25 cm 1 16 cm 3 15 cm

25 Length breadth and height of a cuboid are measured as 1 61 m 2 2 m and 3 1 m The volume of cuboid up to correct number of significant figures is 1 10 98 m 2 1 1 x 10 m 3 10 9 m

Example 16 An electron which is moving with a velocity 5 x 10 m s enters into an electrici quires an acceleration of 10 5 m s in the direction of initial motion In how much time the velody ctron will becomes twice its initial velocity How much distance will electron travel during this in Solution Initial 104 aximum h Solution Gi At maximum By equation o

In the figure shown P and P are mid point of the faces and C is the centre of cube A point charge q is plac away from C on P P 0 0 0 and be the electric flux linked with faces ABCD EFGH ADHE and BC respectively Write decreasing order of and A P 19 H Co B P C

Two charged spherical conductors of radius R and R are connected by a wire Then the ratio of surface charge densities of the spheres 0 0 is 1 2 3 4 R R2 2 R R R2 R R Ra 6 d a 101 EP N 8 1 AL be te DAG FUNT ME

d 10 4 In Young s double slit experiment D d distance between slits D distance of screen from the slits At a point P on the screen the resulting intensity is equal to the intensity due to individual slit lo Then the distance of point P from the central maximum is 6000 Question Type Single Correct Type 1 2 2 mm 1 mm

4R 7 A square loop and a long straight wire are situated in a common plane such that one edge of the square is parallel to the wire The mutual inductance between the wire and loop is 1 HIn 2 41 Hoa 3 Ha 2 In 2 2 4 Hoa 2