Basic Physics Questions and Answers

i The potential energy of a particle in a force field is where A and B are positive constants and r is the distance of particle from the centre of the field For stable equilibrium the distance of the particle is AIPMT Prelims 2012 U 1 AB 2 3 2 r A B B A B 2A 2A

12 One face of a rectangular glass plate 6 cm thick is silvered An object held 8 cm infront of the unsilvered face forms an image 6 cm behind the silvered face Find the refractive index of glass Consider all the three steps 13 A lens with a focal length of 16 cm produces a sharp image of an object in two positions whi

85 A population of lotus plants in a pond is 450 in the starting of January 2014 It has a birth rate of 0 2 lotus plant month The number of plants after 2 months will be a 630 c 610 b 540 d 648

Worth While car A starts with an initial velocity of 10 m s nd an acceleration of 1 m s car B starts from rest with n acceleration of 2 m s Answer the following questions 6 As seen by a passenger in car A 1 Car B moves backward 2 First the car 8 moves backward and then forward O 3 Car B moves forward 4 First the car B moves forward and then backward 7 As seen by a passenger in car B 1 Car A moves backward 2 First the car A moves backward and then forward 3 Car A moves forward 4 First the car A moves forward and then backward The separation between the cars 1 Continuously increases 2 Continuously decreases First increases then decreases and finally increases again 4 First decreases then increases and finally decreases again Taking the moment of start as t 0 the separation between the cars at the moment t 5 s is 37 5 m with A ahead of B 2 37 5 m with B ahead of A 3 50 m with B ahead of A 4 50 m with A ahead of B The position of car A at this moment t 5 s is 1 62 5 m due North of starting point 2 37 5 m due North of starting point 3 62 5 m due South of starting point 4 37 5 m due South of starting point The position of car B at this moment t 5 s is 1 25 m due North of starting point N 4

A cube of volume 1 m and specific gravity 2 is very slowly being lowered in to a lake with help of a massless string tied to one of its vertices as shown Initially the vertex B is just touching the surface of water and finally vertex A is just beneath the surface of water For the process of immersion match the columns Ignore change in KE of water g 10 ms Column 1 A Work done by gravity on water cube system B Work done by tension on the cube C Work done by gravity on water D Work done by gravity on the cube p 3 3 2 9 3 3 r 2 3 2 Column 11 x 104 Joule 10 Joule 10 Joule AT s 2 3x10 Joule t 40 3 10 Joule B

Mark the correct statement A The magnitude of the velocity of a particle is equal to its speed B The magnitude of average velocity in an interval is equal to its average speed in that interval C It is possible to have a situation in which the speed of a particle is always zero but the average speed is not zero D It is possible to have a situation in which the speed of the particle is never zero but the average speed in an interval is zero A A Correct Not Marked By You

wo blocks of mass 10 kg and 5 kg are connected with a light string which is assing over an ideal pulley attached with a fixed smooth wedge If the system is eleased from rest then the acceleration of the blocks will be 5 kg 37 O 5 m s 0 m s 2 m s Read More 10 kg

A soap film n 1 33 is contained within a rectangular wire frame The frame is held vertically so that the film drains downward and forms a wedge with flat faces The thickness of the film at the top is essentially zero The film is viewed in reflected white light with near normal incidence and the first violet 420 nm interference band is observed 3 00 cm from the top edge of the film

A battery of emf 20 V is connected to resistances as shown in figure The potential at the point C will be 302 www O 10 V 08V O 6 V www 192 wwww 322 B wwww 392 www Read More 192

Two identical wires are vibrating in unison If the tension in one of the wires is increased by 2 five beats are produced per second by the two vibrating wires The initial frequency of each wire is 1 02 1 01 1000 Hz A B C D 500 Hz 400 Hz 200 Hz

A solid uniform bar of diameter d and length 1 is hanging vertically from its free end The elongation of the bar due to self weight is a proportional to 1 and inversely prportional to d b proportional to 12 and inversely proportional to d to 1 but independent of di d proportional to 12 but independent of d c proportional

Select incorrect statement regarding mechanical energy of a body system 1 It is sum of kinetic and potential energy 2 It may be conserved even if non conservative force acts on the body system 3 Work done by conservative force is always equal to negative of change in mechanical energy 1 Roth 1 r l

Internal forces acting in a system of particle can change 1 The kinetic energy but not linear momentum of the system 2 Neither linear momentum nor kinetic energy of the system 3 Both kinetic energy and linear momentum of the system 4 The linear momentum but not the kinetic energy of system

mathongo mathongo A ray of light passing through a prism suffers minimum deviation It is found that the hongo mathor mahongo mathor angle of incidence is double the angle of refraction mathongo mathongo within the prism Then the angle of prism is mathongo mathor in degrees

41 In the indicator diay am shown for an ideal gas the heat exchange between the gas and surrounding is zero for process OA The heat exchange will be negative for the process P O 1 B 3 D D B Ai 2 C 4 Both C and D

A beam of unpolarized light of intensity lo is passed through a polaroid A and then through another polaroid B which is oriented so that its principal plane makes an angle of 45 relative to that of A The intensity of the emergent light is A Io 8 B Io C Io 2 D I0 4

Identify the correct statement O A neutron is formed by an electron and a proton combining together Therefore it is neutral Mass of an electron is about 1840 times that of proton O Each energy level in an atom is associated with a fixed amount of energy 14 and 14N shows different 7 chemical reactivity due to difference 6

One radio transmitter A operating at 60 0 MHz is 10 0 m from another similar transmitter B that is 180 out of phase with A How far must an observer move from A toward B along the line connecting A and B to reach the nearest point where the two beams are in phase

India s Superlatives Match the following and mark in the box given below A B 1 Longest River 2 Longest Road 3 Fastest Train 4 Smallest State 5 Largest Residence of the head of India 6 Most Populous City 7 Largest Desert 8 Highest Mountain Peak a National Highway 44 b Kanchenjunga c Ganga also Ganges d Vande Bharat Express e Goa f Rashtrapati Bhawan g Mumbai h Thar

A parallel plate capacitor A of capacitance 1 F is charged to a potential drop 100 volt and then disconnected from the battery Now the capacitor A is completely filled with a dielectric slab of dielectric constant k 4 Another parallel plate capacitor B of capacitance 2 F is charged to a potential drop 20 volt and then disconnected from the battery Now the two capacitors A and B are connected with each other with opposite polarities Then the heat dissipated after connecting the capacitors is A 1 15 10 J C 1 35 10 J B 1 25x10 J D 1 45 10 J

A time varying magnetic field B Kr t is existing in a cylindrical region of radius R as shown where k is a constant The induced electric field E at R is 2 A C KR 20 KR4 60 B D KR 40 KR4 80 B kr t

A thin film of oil n 1 25 is located on a smooth wet pavement When viewed perpendicular to the pavement the film reflects most strongly red light at 640 nm and reflects no blue light at 512 nm How thick is the oil film

A periodic voltage V varies with time t as shown in the figure T is the time period The r m s value of the voltage is V V T 4 T t Question Type Single Correct Type

Monkey A 10 kg is climbing on a pole while B 5 Kg is holding on to the tail of monkey A If monkey A is climbing with acceleration 1 m s and its tail can withstand tension of 65 N before it snaps with what maximum relative acceleration in m s with respect to monkey A monkey B climb on its tail A 10 kg B 5 kg

Q31 In Young s double slit experiment distance between two sources is 0 1 mm The distance of screen from the sources is 20 cm Wavelength of light used is 5460 Then angular position of the first dark fringe is 1 0 08 2 0 16 3 0 20 4 0 32 1 2 3 From NCERT 4

1 04 A ship A is moving Westwards with a speed of 10 km h and a ship B 100 km South of A is moving Northwards with a speed of 10 km h The time after which the distance between them becomes shortest is a 0 h b 5h c 5 2h d 10 2 h

5 In the diagram A and B are two conductors on insulating stands Both A and B were initially uncharged A X Y B i a Conductor A is given the positive charge shown on the diagram i On a copy of the diagram mark the signs of the charges induced at end X and at end Y of conductor B 1 ii Explain how these charges are induced 3 iii Explain why the charges at X and at Y are equal in magnitude 1 b B is now connected to earth by a length of wire Explain what happens if anything to i the charge at X ii the charge at Y 1 2

A bob is circulating in horizontal plane whose radius is constant with the help of ideal str that it forms a conical pendulum Then choose the correct option s Answer A B C Your Attempt Correct answer Angular velocity of the string is constant Magnitude of angular velocity of the string is constant Direction of angular velocity of the string is varying ular velocity are varying Rate this qu

5 An insulated cylinder covered by a weighted frictionless piston of 500 kg and an area of 100 cm contains air at 1 MPa and 300 C The piston is held in position by a stop The environment is air at 100 kPa and 30 C The stop is removed and the piston rises to a new equilibrium position 50 cm higher a Find final pressure of air b Find initial and final volume of air C Calculate the mass of air 50 cm

An electric dipole consisting of two opposite charge of 2 x 10 6 C each separated by a distance of 3 cm is placed in an electric field of 2 x 105 N C The maximum torque on the dipole will be Question Type Single Correct Type 1 12 10 Nm 2 12 x 10 N m 3 24 10 N m

6 Two particles of equal mass m go round a circle of radius R under the action of their mutual gravitational attraction The speed of each particle is 4Gm b v d v R a v Gm VR Gm c v 1 Gm 2 R 2 R tunnel is dug along a straight line

The potential difference between points A and B is A 2V 192 1 4V 192 Question Type Single Correct Type 2 V 3V 19 B 2 6 V

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

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

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

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

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

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

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

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

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

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

A long wire carrying current I is bent into the shape as shown in the figure The net magnetic field intensity at the centre O is A 1 2 C 4 R B D Hol 4TR 4TR 4 R Hol 4TR 9 O

3 Start rotating around earth in a circular orbit 4 Escape from gravitational field of earth Gravitational field intensity 33 A uniform sphere of mass M and radius R is surrounded by a concentric spherical shell of same mass but radius 2R A point mass m is kept at a distance x R in the region bounded by spheres as shown in the figure The net gravitational force on the particle is 1 2 GMm x GMmx R G M m x 3 4 Zero M R m 2R M

Region I and II are separated by a spherical surface of radius 25 cm An object is kept in region I at a distance of 40 cm from the surface The distance of the image from the surface is Wmathongo mathongo mathongo mathongo II 25am C 1 25 mathongo mathongo mathongo Amathange 1 4 1 55 44 cm 2 9 52 cm ng mathongo 3 18 23 cm 4 27 5 mathongo mathongo mathongo mathongo mothongo mathonge mathongo mathongo mathongamathongo mathongo mathongo mathongo mathongo mathango mathongs mathongo mathongo mathongo