Physics Questions

Three concentric conducting spherical shells have radii r 2r and 3r and charges q 92 and q3 respectively Innermost and outermost shells are earthed as shown in figure Select the correct alternative 93 92 91 2r 3r HI

Two periodic waves of intensities and 2 pass through a region at the same time in the same direction The sum of the maximum and minimum intensities is AIPMT Prelims 2008 1 2 1 2 1 1 3 T4 7 4 2

Aakash Institute 0 An astronomical telescope is to be designed to have a magnifying power of 50 in normal adjustment If the length of the tube is 102 cm then power of the objective and the eyepiece respectively is 1 1D 40D 3 50D 1D 2 1D 50D 4 2D 50D

elocity of point on the equator of rotating spherical planet is V The angular velocity of the planet is such that the value of g at the equator is alf of g at the pole The escape velocity for a polar particle on the planet is xV Find x

1 An equiconvex lens is prepared from glass 1 5 having radius of curvature 25 cm One of the surface is silvered from outside Where should an object be placed before this lens so that image is formed on the object itself 1 12 5 cm 3 100 cm 2 25 cm 4 125 cm

point by a A heavy particle hanging from a fixe light inextensible string of length is projected horizontally with speed gl Then the speed of the particle and the inclination of the string to the vertical at the instant of the motion when the tension in the string equal the weight of the particle A 31 0 C 3g cos 3 2 B cos 2 3 D lg V 3 cos 2 3 sin 2 3

a Determine the electrostatic potential energy of a system isting of two charges 7 C and 2 C and with no external field placed at 9 cm 0 0 and 9 cm 0 0 respectively b How much work is required to separate the two charges infinitely away from each other c Suppose that the same system of charges is now placed in an external electric field E A 1 r A 9 x 105 C m2 What would the electrostatic energy of the configuration be Solution 1992 9x10 x 4TE T b W U U 0 U 0 0 7 0 7 J c The mutual interaction energy of the two charges remains unchanged In addition there is the energy of interaction of the two charges with the external electric field We find q V q V 1 A and the net electrostatic a U 7 2 10 2 0 18 7 C 0 09m A 2 C 0 09m Scanned by TapScanner energy is ZUC 0 7 J RUC

42 If a particle loses 20 of its speed after penetrating through a single plank Calculate the minimum number of planks required to completely stop the plank 1 6 3 4 2 8 4 3

ALLE A uniform sphere is placed on a smooth horizontal surface and a horizontal force F is applied on it at a distance h above the centre The acceleration of the centre of mass of the sphere 1 is maximum when h 0 2 is maximum when h R 3 is maximum when h R 2 4 is independent of h a F

Consider an earth satellite moving with a speed 8200 m s at perigee which is 340 km above the earth s surface Calculate distance to the satellite from the earth s surface when t is at apogee Radius of earth is 6 4 100 m a 2340 km b 4580 km c 3520 km d 1850 km

The sum of the magnitudes of two forces acting at a point is 16N The resultant of these force is perpendicular to the smaller force and has a magnitude of 8 N If the smaller force is of magnitude x then the value of x is A 2 N B 4 N C 6 N D 7 N

In the figure shown is coefficient of friction between cylinder inclined surface Here e is continuously increased Find out required condition so that i sliding occurs earlier ii toppling occurs earlier 0 b

A glass rod of diameter d 1 5 mm is inserted symmetrically into a glass capillary with inside diameter d 2 0 mm Then the whole arrangement is vertically oriented and brought in contact with water To what height in cm will the water rise in the capillary Given surface tension of water 75mN density of water 10 kg m g 10 m s

n electron beam having energy 2 eV incidents on a potential barrier having width 0x10 0 m and height 4 eV Calculate the transmission probability for the electron a 9 98 10 3 b 9 98 10 3 c 0 d 9 98 10

2015 An electric dipole consists of two opposite charges each of magnitude 1 0 C separated by a distance of 2 0 cm The dipole is placed in an external field of 105 NC The maximum torque on the dipole is a 0 2 x 10 3 Nm c 2 10 Nm b 1 10 Nm d 4 10 Nm COMEDK

m 1 1 1 39 A compound microscope has a magnifying power of 400 when the image is formed at infinity The objective has a focal length of 0 5 cm and the tube length is 18 cm The focal length of eye piece is Normal near point is 25 cm 1 5 5 cm 2 9 5 cm 3 15 5 cm 4 2 25 cm

34 A ray of light incident at an angle 8 on the refractingeetde face of a prism emerges from the other face normally If angle of the prism is 5 and it s refractive index is 1 5 the angle of incidence is nearly 1 7 5 2 5 3 15 4 2 5 35 What should be the maximum value of 0 such that 38

Q15 Two inductor coils of self inductance L 10 H and L 20 H are placed as shown in the figure The mutual inductance of the coil is 3H The equivalent inductance between AB of the system of coils is 000000 000000 1 36 H 2 24 H 3 H 4 H 51

distance D capable of screen will separated D f Ray Optics and Optical uments 27 In an astronomical telescope using objective and eyepiece of focal length 50cm and 5cm length of telescope obtained is 54 5cm when the final image of a star was at distance x cm from the eyepiece Find x 1 35 3 25 2 45 4 15

ging lens 1 Bcal lengin 4 In a spherical paper weight R 10 cm made of glass of refractive index 1 5 and object is embedded at a distance 5 cm from its centre What is the apparent position of the object when seen from the opposite side R D C 5 cm 1 10 cm behind centre 2 10 cm behind P 3 15 cm behind centre 4 5 cm behind P 2

The length of an astronomical telescope adjusted for parallel light is 90 cm If the magnifying power of the telescope is 17 then the focal length of eyepiece and objective are respectively 1 10 cm and 80 cm 2 85 cm and 5 cm 3 70 cm and 20 cm 4 5 cm and 85 cm

Charge 4 uc and 9 uc lies at 100 m distance find point on line joining charges where electric field zero Find out point where electric field is Zero but electric potential not zero Find out point where electric potential is zero but electric field not zero

m m In the above figure are the surfaces are smooth m is at rest m is given velocity as shown For which of given value of m will the number of collision between m and m is only 1 coefficient of restitution 1 and all surfaces are smooth SolveLancer Test 1 m 4 m 11 m 1 5 m III m 2m IV m 3 5 m a I II b II IV c III IV d II III CO a b C

6 The chain is released see figure What is the speed when it slips by length 4 L 2 re mag 1 3 If the z 3 gL 16 3gL 8 8 4 a Exem 2 4 M L 2 5gL 8 5gL V 16 6 he Tirts F 6 Pol

A particle is moving under the potential V x cx dx Here c and d are constant The particle is at rest initially and is at stable point Calculate the minimum speed of the particle when it reached to unstable point a Vmin b Vmin c v min d v min d 27mc 8d 27mc 2d 9mc 16d 27mc

A 100 kVA single phase transformer has iron loss of 600 W and a copper loss of 1 5 kW at full load current Calculate the efficiency at i full load and 0 8 lagging pf and ii half load and unity pf

A cork is suspended from the bottom of a container filled with water with a string as shown in figure The container accelerates in a horizontal direction towards right Then the inclination of the string with vertical is a tan a g towards left b tan a g towards right c cot a g towards left d cot a g towards right

PLEASE EXPLAIN ALL OPTION HOW to know TYPE OF PO ARIZATION An electromognetic wave travels in vacuum along z direction E E i E j cos kz wt Choose the correct options from the following a The associated magnetic field is given B E E cos kz wt b The associated magnetic field is B E i E cos kz oot QU c The given electromagnetic field is circularly polarised d The given electromagnetic wave is plane polarised as as

A far sighted person can see object beyond 49 cm clearly If separation between glasses and eye len is 1 cm then find focal length of glass 1 30 cm 2 25 cm 3 24 cm 4 48 cm

An object with a mass 5 kg moves at a constant velocity of 8 m s A constant force then acts for 6 seconds on the object giving it a speed of 4 m s in opposite direction The acceleration produced is 1 1 5 m s 3 0 67 m s 2 2 m s 4 0 5 m s

3 A particle is thrown with a velocity of u m s It passes A and B as shown in figure at time t 1 s and t 3 s The value of u is g 10 m s AY U 30 O 1 20 m s 3 40 m s A B 2 10 m s 4 5 m s

From the concept of directed dimension what is the formula for a range R of a cannon ball when it is fired with vertical velocity component Vy and a horizontal velocity component V assuming it is fired on a flat surface Range also depends upon acceleration due to gravity g and k is numerical constant R R k VzV 9 k V 9 k V Vg 3 k V Vz9

Where should an object be placed in front of concave mir ror of focal length 15cm to have magnification of 3 sir why it is taken as 3 Where should an object be placed in front of a concave mirror of focal length 15 cm to have a magnification of 3 in case of a real image b virtual image

When a diffraction pattern of a crystalline solid is recorded using an X ray beam of wavelength 0 26 nm the first order diffraction peak occurs at a scattering angle of 35 If the error in the measurements of angle and wavelength are 1 and 0 01 nm respectively then determine the error in measuring the interplanar spacing a 22 86 nm b 32 38 nm c 15 2 nm d 13 2 nm

A ring of mass m and radius R carrying current I is rotating with angular speed wo Magnetic field B perpendicular to plane of the rin exist in the region as shown Tension 7 developed in the ring is X X 2 Options R mo loB 2 mo 2 B mo aloB mo3 2 B R 2 X R 2

The horizontal position of a car in kilometres over time is shown below Position Kilometres 160 120 80 40 80 10 Time hours a Find the displacement and the distance travelled by car between 1 hour and 3 hours Ans Okm Okm b What is the displacement and distance covered by the car between 3 hours and 5 hours Ans 120km 120km c Calculate the displacement and the distance travelled by car between 5 hours and 9 hours Ans 160km 160km d Find the displacement and the distance covered by the car

The line graph given below shows the sales of three car companies A B and C during the period 2005 2010 What is the approximate growth percentage of total sales of three companies from 2005 to 2010 Sales in units 4000 3500 3000 2500 2000 1500 1000 500 0 2005 2006 2007 2008 2009 2010 Year A B C

A particle of mass m is released from rest and follows a parabolic path as shown Assuming that the displacement of the mass from the origin is small which graph correctly depicts the position of the particle as a function of time set of b c X t d 4x t 4 x t A 4x t V x 4 2011

n ice cube is floating in water above which a layer of lighter oil is poured As t e melts interface and the uppermost level of oil will respectively AT FIN 111 Ice rise and fall not change and not change HAN MIT Interface 2 fall and rise 4 no change and fall

25 A presbyopic old patient has near point 30cm The optical power for the corrective lens for seeing object placed at normal near point 25cm is 2 76 IN NI ED 3 compound microscopo UGOD On biootivo long

Aakash Institute 22 A luminous object and a screen are fixed distance D apart A converging lens of focal length capable of forming a real image of the object on the screen will do so for two positions of the lens that are separated by distance d such that 1 d D D 4f 3 d D D 4f 2 d D D f 4 d D 2D f 27 In a eye tele of a Fina 1 3 28 An

A disc of radius R pivoted at point 0 oscillates in the plane of paper as shown in figure The distance of point O from centre of mass of disc is x Ruch achdi O far uz hacha 3 A Aa tey ggur h da da se za 21 A fare B A 2 2gx x R C D Xic R Time period of oscillations of disc is R 2x Correct Answer R G J 1 2 1 Correct Answer 2 time period is minimum 2 R 2x 2gx 2 Correct Answer The minimum time period is 2 2R 9 The minimum time period is 27 2R g R

8 A projectile is projected at some angle from the ground towards east in the absence of air resistance then time period and range of projectile are T and R If wind starts blowing towards east with some acceleration then the new time period T and range R have the relations 1 T T and R R 2 T T and R R 3 T T and R R A T I and R S P

5 A ray of light travelling in a transparent medium falls on a surface separating the medium from air at an angle of incidence of 45 The ray undergoes total internal reflection If n is the refractive index of the medium with respect to air select the possible value of n from the following 1 1 2 3 1 4 2 4 3 4 1 5

66 An electric dipole of moment P is released in a uniform electric field E from the position of maximum torque Angular speed of the dipole when P becomes parallel to E will be moment of inertia of dipole T PE 21 3 2PE 4PE 2 4 PE 2 DE m

B 1 1 x 1 x be an ordered basis of polynomials in P Write down the coordinate vector of the polynomial asis in the form a b c 7 points Save Answer 1 2x x 2 relative to this given

the correct statement s regarding the motion of a particle A If instantaneous velocity of a particle is zero then its instantaneous acceleration wil necessarily be zero B If instantaneous velocity of a particle is zero then it can have instantaneous acceleration C A situation is possible in which instantaneous velocity of a particle is never zero but average velocity in that interval is zero D A situation is possible in which the speed of a particle is never zero but average speed in that interval is zero

A particle is moving in a three dimensional potential V x y z mo 2x y 42 If the mass of the particle is m then what is the energy of the particle in the lowest quantum State a b c 7 2 o 3 2 2 ho 3 3 re 3 d o

3 2 cm 4 13 cm 3 The magnifying power of a microscope with an objective of 5 mm focal length is 400 The length of its tube is 20 cm The focal length of eye piece is final image formed at infinity 1 200 cm 2 150 cm

14 A convex lens forms a real image on the screen with magnification m If lens is moved a distance x again a real image is formed with magnification m Then focal length of the lens is 1 X 3 xlm m l 2 Jm m X m m