Physics Questions

A long coaxial cable carries current I Current flows down the surface of the inner cylinder of radius a and back along the surface of outer cylinder of radius 2a as shown The self inductance per unit length of the coaxial cable is yg a augu hda wa ugu fh g 21 ER AU a kc udz 92 gmiza ata am taf xzur A642 2a dy da dg jfta mua ata Zi ad amefu da c uf c at za zcca a tic A B Holn2 4 2 ln2 Holn2

When 100 g of boiling water at 100 C is added into a calorimeter containing 300 g of cold water at 10 C temperature of the mixture becomes 20 C Then a metallic block of mass 1 kg at 10 C is dipped into the mixture in the calorimeter After reaching thermal equilibrium the final temperature becomes 19 C What is the specific heat of the metal in C G S units

In an experiment to find focal length of a convex lens by displacement method magnification obtained are 2 and respectively for two positions of lens separated by distance d 30 cm Focal length of lens is 2 14 A 10 cm B 20 cm C 30 cm D 40 cm 15 Distance between two pins to locate positions of object and image is A 60 cm B 90 cm C 120 cm 16 object pin and lens when magnification m 2 is obtained is B 20 cm C 30 cm D 40 cm Distance between A 10 cm D 150 cm

Three rods of equal length are joined together and clamped at their ends as shown in the figure The upper and lower rods are identical a Y and the middle one is of different material Y Find the final length of the system if the temperature is increased from T to T Consider no bending and a d 1 Y a2 Y a Y

A swimmer crosses a rive of width d flowing at velocity v While swimming he heads himself always at an angle of 120 with the river flow and on reaching the other end he finds a drift of d 2 in the direction of flow of river The speed of the swimmer with respect to the river is 1 2 3 v 3 4 2 3 v 2 2 2 3 v 4 2 3 v

A cylindrical block of wood floats vertically with 80 of its volume immersed in a liquid at 0 C When the temperature of the liquid is raised to 62 5 C the block just sinks in the liquid The coefficient of cubical expansion of liquid is A 1 10 K 1 B 2 10 K 1 C 3x10 K 1 D 4 10 K 1

There are three bulbs B B2 and B3 rated as 100 W 60 W and 60 W respectively These can be operated upto 200 V Increasing order of their brightness for given arrangement is B B B 100 V B3 B2 B B B B3 B B B3 B B3 B

A ball is projected with velocity Vo at an angle of elevation 30 Mark the correct statement Kinetic energy will be zero at the highest point of the trajectory Vertical component of momentum will be conserved Horizontal component of momentum will be conserved Gravitational potential energy will be minimum at the highest point of the trajectory

3 Two long parallel straight wires X and Y separated by a distance of 2 5 cm in air carry currents of 5 A and 2 5 A respectively in opposite directions Calculate the magni tude and direction of the force on a 10 cm length of the wire Y CBSE 04 10 5N repulsive normally away from X

SolveLancer Test What is the resistance offered by a capacitor and an inductor to a 12 V DC supply at steady state SolveLancer Test b a Infinite by capacitor and Zero by inductor Zero by capacitor and Infinite by inductor It will vary depending upon the value of capacitor and inductor c d Cannot be determined

Q33 A parallel plate capacitor of area A plate separation d and Capacitance C is filled with three different dielectric materials having dielectric constants K K K3 as shown If a single dielectric material is to be used to have the same capacitance C in this capacitor then its dielectric constant K is given by a c d 1 1 K 1 1 K 1 K K2 K K K K2 K K3 K K3 K K3 K K3 1 K3 1 2 K3 2K3 d A 2 K1 K3 Q A 2 K2 H

1 A particle of mass 2 kg is moving in circular path with constant speed 20 m s The magnitude of change in velc when particle travels from A to P will be f P V 1 20 2 m s 3 40 2 m s A particle is in uniform circular motion then its volonitui 2 40 m s 4 Zero

11 The minimum magnifying power of a telescope is 100 If the focal length of eye piece becomes one third the minimum magnifying power will becomes 1 300 2 100 3 3 100 3 4 900

The work done by gravity exerting an acceleration of 10 m s for a 10 kg block down 5 m from its original position with no initial velocity is grav mass x acceleration and W F x dx 1 250 J 2 500 J 3 100 J 4 1000 J

3 55 cm 4 45 cm 9 In displacement method there are two positions of a lens for which two distinct images are formed on a screen First position of the lens is at a distance of x from the object and second is at a distance 2x the focal length of the lens is 001 1 3 object x 3 2x 3 H X 1 2x 2 2x 4 6x

A particle of mass M moving in a straight line with speed v collides with a stationary particle of the same mass In the center of mass coordinate system the first particle is deflected by 90 The speed of the second particle after collision in the laboratory system will be a v 2 b 2v c v d v 2

2 38 A dancer leaps off the floor with her centre of mass having a velocity of 5 m s making an angle of 0 37 to the horizontal At the top of the trajectory the dancer has her legs stretched so that the centre of mass gets closer to head by a vertical distance of 0 25 m By how much does the head rises vertically from its initial position sin 37 3 5 G

The magnitude of the electric field is 1000 N C at a point located at d 2 5 m away from a long uniform line of charge Find the distance in cm away from the line at which the magnitude of the electric field is 6000 N C 21 d E

A uniform horizontal electric field E is established in the space between two large vertical parallel plates A small conducting sphere of mass m is suspended in the field from a string of lengt L If the sphere is given charge q then te period of oscillation of the pendulum is B 2T A 2 L g C 0 2 L Vg qE m 2 g 2 L qE m 2 L Vg qE m

0 A bulb is placed at a depth of 2 7 m inside water and a floating opaque disc is placed over the bulb so that the bulb is not visible from the surface The minimum diameter of the disc is Refractive index of water is 4 3 1 6m 3 12m 2 9m 4 14m

97 In a tank a 4 cm thick layer of water 3 floats on a 6 cm thick layer of an organic liquid u 1 50 Viewing at normal incidence how far below the water surface does the bottom of tank appear to be 1 4 cm 3 6 cm 2 5 cm 4 7 cm

Impulse due to a force on a body is given by I fFdt If the force applied on a body is given as a function of time t as F3t 2t 31 2t 5 N 5 N then impulse on the body between t 3 sec to t 5 sec is 1 175 kg m sec 2 41 kg m sec 3 216 kg m sec 4 124 kg m sec

0 A lens having focal length f and aperture of diameter d forms an image of intensity I in central region of d Aperture of diameter c f and lens is covered by a black paper Focal length of lens and intensity of image now will be respectively CBSE AIPMT 2010 a f and and 1 4 3 4 2 b 3f 4 d and 2 2 2

4 If mass of the electron 9 1 x 10 31 Kg Charge on the electron 1 6 10 19 coulomb and g 9 8 m s Then the intensity of the electric field required to balance the weight of an electron is A 5 6 x 109 N C C 5 6 x 10 8 N C B 5 6 10 11 N C X D 5 6 x 10 7 N C

107 A system of two concavo convex glass system as shown in the figure of radius of curvature 50 cm 1 25 cm 3 Zero rar 3 2 each and respective refractive indices and The focal length of the system is 3 2 100 cm 4 Infinite 13 4

A Bohr hydrogen atom undergoes a transition n 5 to n 4 and emits a photon of frequency f The frequency of circular motion of electron in n 4 orbit is f The ratio is found out to be 2p 25 Find the value of p h

TUS A pulley of radius 2m is rotated about its axis by a force F 20t 5t newton where t is measured in second applied tangentially If the moment of inertia of the pulley about its axis of rotation is 10kg m The number of rotations made by the pulley before its direction of motion reversed is More than 3 but less than 6 2 More than 9 3 More than 6 but less than 9 4 less than 3

105 When a lens of power PO and refractive index u is kept in a medium of refractive index 0 its power will be 106 1 PO PH 3 1 Ho 2 4 P Ho P H 1 H person having poor point 10 murer reading

Ray Optics and Optical Instruments 34 For the given figure the possible value of for which image is formed on the right of sphere at a distance R from the sphere is 1 1 5 3 2 object O R R 2 1 33 4 2 5

The profit function for a product is given by P x x 3 4x 2 400x 1200 where x is the number of units produced and sold and P is in hundreds of dollars Use factoring by grouping to find the numbers of units that will give a profit of 40 000 The numbers of units that will give a profit of 40 000 are Type an integer or a fraction Use a comma to separate answers as needed

The mean free path of the particles of a gas at a temperature To and pressure po has a value If the pressure is increased to 1 5p and the temperature is reduced to 0 75 To the mean free path a remains unchanged b is reduced to half c is doubled d is equal to 1 125

5 ABC is a right angled prism of transparent material of refractive index such that ZB is smaller than ZA as shown in figure A ray of light incident normally on the face AB emerges parallel to the incident ray after two internal reflections then theeet minimum value of is 1 3 1 sin A sin A sin R C 2 sinB B Telegram oeet 4 sin A sin B

The circular wire in figure below encircles solenoid in which the magnetic flux is increasing at a constant rate out of the plane of the page Path 2 A 0 0 B Eo 0 C EO E0 DI wire Path 1 The clockwise emf around the circular loop is so By definition a voltammeter measures the voltage difference between the two points given by Vb V E ds We assume that a and b are infinitesimally close to each other The values of Vb Va along the path 1 and Va Vo along the path 2 respectively are

In the figure shown a block of mis attached to a light spring of force constant K and an identical spring hangs from ceiling initially lower spring is in compressed state with 3mg compression equal to When block is k released it strikes upper spring and sticks to it What is the amplitude of oscillation in cm after sticking Given mg 20 N K 100 7 N m Terfy fa m yg ych s da Audich K Ich sch c a fu ja ar huga M va ach 3 3 42 4 7 A d A a 392 2 Mag 4 437 gia ad ug Tu Auch a 1 100 7 N m 20 N K mg k reelle reelle k k 3mg k Equilibrium NCRET RR mg

A A body is at rest at x 0 At t 0 it starts moving in the positive x direction with a constant acceleration At the same instant another body passes through x 0 moving in the positive x direction with a constant speed The position of the first body is given by x after time t and that of the second body x after the same time interval Which of the following graphs correctly describes x x as a function of time 1 3 12 x L X 2 4 X X 2 X1 X 2

A Youngs double slit experiment is immersed in a liquid of refractive index The slit plane touches the liquid surface A parallel beam of monochromatic light of wavelength with respect to air is incident normally on the slits Choose the correct statement s of the following screen d 21 1 cos Liquid S JAYA YEVA A The fringe width is B If one of the slits S is covered by a transparent slab of refractive index and thickness t the new position of the central maximum will shift up by 2 1 tD d C The ratio of the intensities at O in the conditions of the option A and option B is 17 1 D If a slab of thickness t and refractive index 3 is introduced in front of S and S is also covered by a slab of thickness t and refractive index as shown in the figure then for relation 1 the central maxima will be at O

91 A far sighted person has his near point 50 cm Find the power of lens he should use to see at 25 cm clearly 1 1D 2 2D 3 2D 4 1D 2 A microscope has an objective of 5 mm focal 9

Q4 For the circuit shown in Fig below determine the current through RL when its value is 50 2 Find the value of RL for which the power drawn from the source is maximum 10 w 50V www 20 ww 15 15 M 30 M R

An infinitely long closely wound solenoid carries a sinusoidally varying current The induced electric field i a zero everywhere b non zero inside and zero outside the solenoid c non zero inside as well as outside the solenoid d zero inside and non zero outside the solenoid

A particle of mass m moving along the quarter section of the circular path whose centre is at the origin The radius of the circular path is a m A force F v x N acts on the particle where x y denotes the co ordinates of position of the particle Calculate the work done by the force in taking the particle from point A a 0 to point B 0 a along the circular path B 0 a

4 In the figure shown For an angle of incidence 45 C at the top surface what is the minimum refractive index needed so that no light will emerge from vertical face AD 1 3 2 1 2 paper D 13 2 2 C 4 2

ne of these 81 An astronomical telescope has an angular magnification of magnitude 5 for distant objects The focal length of objective and the eye piece are 30 cm and 6 cm respectively Then the length of the tube of telescope will be 1 36 cm 3 5 cm 32 The distance between an obiect 2 30 cm 4 150 cm gram 87 speec 1 5 3 1 In a follow devia 1 8

A uniform rod of length 7 cross section area A and Young s modulus Y is placed on a smooth horizontal surface Two horizontal forces 3F and 2F are applied at the ends of the rod as shown If the elastic potential energy stored in the rod is U n 19F 1 12AY Find the value of n

Aakash Institute 5 Spherical aberration in a thin lens can be reduced by 1 Using monochromatic light 2 Using a doublet combination 3 Using a circular annular mask over the lens 4 Increasing the size of lens

Two dipoles are oriented as shown Dipole 1 consists of point charges 22 nC and 22 nC separated by 6 mm Dipole 2 consists of point charges 29 nC and 29 nC separated by 2 mm Location A is at distance d 0 56 m from the center of each dipole Dipole 1 Dipole 2 A a 10 points What is the electric field vector at location A due to dipole 1 b 10 points What is the electric field vector at location A due to dipole 2 c 10 points What is the net electric field vector at location A due to both dipoles

If A 2i 4j 5k the direction cosines of the vector A are 8 22 direction cosines or directional cosines of a vector are the cosines of the angles between the vector and the three ve coordinate axes 4 1 2 3 4 2 45 T 11 4 45 3 1 45 2 45 and 2 45 and 0 and 5 45 and 3 45 4 45 5 45

The figure shows a closed Gaussian surface in the shape of a cube of edge length 1 50 m with one corner at x 4 20 m y 3 70 m 2 807 3 60 y 3 40 kN C with y in meters What is the The cube lies in a region where the electric field vector is given by net charge contained by the cube x X

Aakash Institute 73 A convex lens makes a real image 4 cm long on a screen When the lens is shifted to a new position without disturbing the object or the screen we again get a real image on the screen which is 9cm long The length of object must be 1 2 25 cm 2 6 cm

A particle of mass M is attached to two identical springs of unstretched length L and spring constant k The entire system is placed on a horizontal frictionless table as shown in the figure The mass is slightly pulled along the surface of the table and perpendicular to the lengths of the springs and then let go Using the Lagrangian equation s of motion show whether the mass will execute simple harmonic motion If so find the time period 100000000 000000001

106 A person having near point 40 cm uses a reading lens of focal length 10 cm The maximum magnification he can obtain is 1 4 3 3 5 2 5 4 Infinity ram neet