Physics Questions

The ends of the two rods of different materials with their thermal conductivities radii of cross section and lengths in the ratio 1 2 are maintained at the same temperature difference If the rate of flow of heat in the larger rod is 4 cal sec that in the shorter rod will be in cal sec 1 1 2 2 3 8 4 16 d no rhown in figure a 20 cal of heat flows through it in 4

1 2 rl W trl cost W 3 2 rl cost The radii of the two columns is U tube are r and r When a liquid of density p angle of contact is 0 is filled in it the level difference of liquid in two arms is h The surface tension of liquid is g acceleration due to gravity pghr r 1 2 5 2 pgh r r 21 1 2 3 2 1 1 pghr r 4 pgh 2 1 1 illery tube is

The r m s velocity of hydrogen molecules at tempreature T is seven times the r m s velocity of nitrogen molecules at 300 K This temperature T is Molecular weights of hydrogen and nitrogen are 2 and 28 respectively A B C D 1050 K 1700 K 1350 K 2100 K

A cylindrical tube L 125 cm is resonant with a tuning fork of frequency 330 Hz If it is filling by water then to get resonance again minimum length of water column is Vi 330 m s air A 50 cm C 25 cm B 60 cm D 20 cm

Consider the circuit below E 48 0 V internal resistance is negligible R 102 C 5 F and C 10 F After the capacitors reach their final charges charge on C is q 20 C What is R R fe tama E R C C

A flywheel is rotating about a fixed axis and has kinetic energy of 450 J when it angular speed was 30 rad s1 The moment of inertia of wheel about the fixed axis is O 1 kg m 2 kg m 0 5 kg m 4 kg m

A long metallic bar is carrying heat from one of its ends to the other end under steady state The variation of temperature 8 along the length x of the bar from its hot end is best described by which of the following figures AIEEE 2009 1 2 3 4

beam of unpolarized light passes through two ideal polarizing filters with different ientations as shown in the figure What is the ratio of the final intensity of the beam to the tial intensity Incident light 40 O O 50 Transmitted light

English Two particles of equal charge after being accelerated through the same potential difference enter in uniform transverse magnetic field and describe circular paths of radii R and R respectively Then the ratio of their masses m m is View in V

British 1 colour 2 labour 3 traveller 4 counsellor 5 centre 6 theatre 7 organise 8 realise 9 defence 10 offence American color labor traveler counselor center theater organize realize defense offense

View in English A 2 V potentiometer is used to determine the internal resistance of a 1 5 V cell the balance point of the cell in the open circuit is 75 cm When a resistor of 10 Q is connected across the cell the balance point shifts to 60 cm The internal resistance of the cell is O 1 50 O 250 350 O 4 50

If an electron enters into space between the plates of parallel plate capacitor a an angle of 30 with the plates and leaves at an angle of 60 to the plates The ratio of its kinetic energy while entering the plates to that while leaving will be 01 3 03 1 02 3

Three capacitors each of capacitance C microfarad are connected in series An exactly similar set is connected in parallel to first one The effective capacity of combination becomes 8 F The value of C in microfarad is O 12

A charged particle of charge q and mass m is released from state of rest in an electric field of constant magnitude E The KE gained by particle after t seconds is q Et 2m 2E 2 q m E 212 2m

The figure shows a system of two concentric spheres of radii r and r and kept at temperature T and T respectively The radial rate of flow of heat in a substance between the two concentric spheres is proportional to 1 r 1 r r 2 In 1 r r 1 4 3 T T 2 512 2 r r 4 r r AIEEE 2005

Two positive charges Q and Q2 are fixed at A and B A unit positive charge is taken from A to B along the line joining AB The force experienced by unit charg O Decreases continuously O Increases continuously Increases first and then decreases Decreases first and then increases

Two identical capacitors 1 and 2 are connected in series to a battery as sho in figure Capacitor 2 contains a dielectric slab of dielectric constant K as shown Q and Q2 are charges stored in capacitors Now dielectric slab is removed and corresponding charges are and then K 1 K Q K 1 2K E

The stove has a room temperature of 21 C until it is lit When lit the temperature of the stove rises by 9 C every minute a What is the temperature of the stove after being lit for 20 minutes b The meal has to be baked at a temperature of 318 C How many minutes does it take to heat the stove to the right temperatu

02 A parallel plate capacitor with air between plates has capacity of 1 pF Now plates are moved apart with insulating handle so that separation is twice of original value The space between plates is filled with a medium of dielectric constant 6 The new value of capacity in pF is 03 01 Mark for Review 6 hr

4 50 C in both the above cases The energy emitted per second by a black body at 1227 C is E If the temperature of the black body is increased 2727 C the energy emitted per second in terms of E is 1 16 E 2 E 3 4E 4 2E

Is this a stable equilibrium position for a charged particle placed at this point Discuss the nature of the equilibrium 19 A semicircular ring of radius R is carrying a charge q uniformly distributed over its length Calculate the magnitude of the electric field at the center of the ring Can you calculate the field without using integration For your sake of information Archimedes could have done so 20 Use problem 15 to generate 10 C charge starting with a shell carrying a charge 1 C

3 32 4 64 The temperature of the two outer surfaces of a composite slab consisting of two materials K and 2K and thickness x and 4x respectively are T and T T T The rate of heat transfer through the slab in a steady state is A T T K X with f equal to T K 2K AIEEE 2004

Which of the following radiations has the least wavelength 1 y rays 2 B rays 3 rays 4 X rays If the termpreature of the sun were to increase from T to 2T and its radius from R to 2R then the ratio of the radiant AIEEE 2003

1 A capacitor having capacitance 1 F with air is filled half half with two dielectrics as shown How many times capacitance will become 1 12 2 6 3 88 4 3

are connected with weight less spring as shown The system is resting on the support S If the support S is quickly removed then acceleration of each weight just after the removal of S are Given m m m 2m 5 00000000 m support 1 a g m s a2 2g m s Xal 2 a g 2 m s a 1 78 3 3 a 0 a g m s 2 8 m s

m A compound slab is composed of two parallel layers of different material with thicknesses 3 cm and 2 cm The temperatures of the outer faces of the compound slab are maintained at 100 C and 0 C If conductivities are 0 036 cal cm sec C and 0 016 cal cm sec C then the temperature of the junction is 1 40 C 2 60 C 3 100 C 4 50 C of cross section are joined as shown One end is kept at 100 C

A infinite line charge produces a field of 9 x 104 N C at a perpendicular distance of 2 cm The linear charge density is 107 Cm O 2x 10 6 Cm 1 10 Cm O4x 107 Cm1

2 A parallel plate capacitor of capacity 5 F and plate separation 6 cm is connected to a 1 V battery and is charged A dielectric of constant 4 and thickness 4 cm is introduced into the capacitor The additional charge that flows into the capacitor from the battery is 1 2 C 2 3 C 3 5 C 4 10 C

If the termpreature of the sun were to increase from T to 2T and its radius from R to 2R then the ratio of the radi energy received on earth to what it was previously will be 4 ATM AIEEE 201 1 4 2 16 3 32 4 64 The temperature of the two outer surfaces of a composite slab consisting of two materials K and 2K and thickne

m The coefficients of thermal conductivity of copper mercury and glass are respectively K K and K such that K K K If the same quantity of heat is to flow per second per unit area of each and corresponding temperature gradients are X X and X m 1 X X K in 3 X X X m g 2 X X X m 4 X X X m 1 CC The

In the given figure a circuit is shown In this figure galvanometer G will have zero deflection only wh P www OPQ RS OPR QS OPS QR www S www For any relation between rocictonco

plates 59 An air filled parallel plate condenser has a capacity of 2 pF The separation 81 doubled and the interspace between the plates is filled with wax If the capacity is increased to 6 pF the dielectric constant of wax is 1 2 3 4 2 3 4 6

Two identical positive charges are fixed on the y axis at equal distances from the origin O A particle with a negative charge starts on the x axis at a large distance from O moves along the x axis passes through O and moves far away from O Its acceleration a is taken as positive along its direction of motion The particle s acceleration a is plotted against its x coordinate Which of the following best represents the plot A C 0 a B a D

In the given circuit the potential difference between A and B is 18 V and charge on 2 F capacitor is 24 C The value of C is a cv 244 181 6X18 2 F HH A 1 1 F az cv 6 F HH 108 0 HH 12V 2 2 F B 108 24 1 x 2

A 100 eV electron is fired directly towards a large metal plate having surface charge density 2 x 106 C m 2 The distance from where the electron is projected so that just fails to strike the plate is 0 44 mm 0 66 mm O 0 32 mm O 0 16 mm

In the given circuit the sources are ideal and have emf s E 4 V and E2 1 V and the resistance are equal to R 100 R 200 and R3 300 The potential difference VB V across the plates of the capacitor is V MM R 3 R m C AB E R wi I E

57 A parallel plate air capacitor has capacitance C Now half of the space is filled with a dielec material with dielectric constant K as shown in figure The new capacitance is C Then 1 C 11 K 2 3 C C1 K Air 2 C C 1 K 4 C C K

An electric dipole charges q q masses m each is placed along x axis with its positive charge at 0 0 and the exists in the region Find the angular acceleration of negative charge at a 0 A variable electric field E Ax the dipole A B E Aaq ma 2 E Aa q GO ma 2E Aa q ma D None of these

2 58 A parallel plate air capacitor has capacitance C Half of space between the plates is filled wit dielectric of dielectric constant K as shown in figure The new capacitance is C Then c k K 1 C C 3 C K 1 2C Air 2 C C 2K K 1 4 C C 1 K

The insulation property of air breaks down at E 3 x 105 V m The maximum charge that can be given to a sphere of radius 3 m is 03 10 4 C 09x 10 4C 0 6 10 4 C O 4 x 105 C

View in English A deuteron of kinetic energy 50 keV is describing a circular orbit of radius 0 5 m in plane perpendicular to magnetic field B The kinetic energy of proton that describe a circular orbit of radius 0 5 m in the same plane with the same magnetic field B is O200 keV O 50 keV O100 keV O 25 keV

A hollow uncharged metallic shell of radius R has a charge q at a distance R 2 from the center Find the charge that will flow into the shell after the shell is earthed A q B 2q C q 2 D zero

The coil of a dynamo is rotating in a magnetic field The developed induced emf changes and the number of magnetic lines of force also changes Which of the following conditions is correct que V GR fa emffaf ata a ter tufafa at Affi A Lines of force minimum but induced emf is zero an tani B emf Lines of force maximum but induced emf is zero tag aften f C Lines of force maximum but induced emf is not zero ten af f D Lines of force maximum but induced emf is also maximum ad temi affemf

A particle of charge q is released from rest from a point A It moves due to a electrostatic field in this region to a point B If VA and VB are the potentials of A and B respectively then neglecting electromagnetic radiation the kinetic energy of the particle at B is A q VA VB B q VB VA C q VA VBI D qVBl JI

A simple harmonic oscillator has an amplitude a and time period T The time required by it to travel from x a tox a 2 is Rad and f Sara T A T 6 B T 4 C T 3 D T 2 x A 2 Your Answer A 32

charge will be same 38 Two plates area s charged to q and 92 9 q are brought closer to form a capacito of capacitance C The potential difference across the plates is 39 1 3 91 92 2C 91 92 For a on 2 4 91 92 C 2 9 92 C

A dielectric sphere of radius R carries a uniform charge density Calculate the electric field at a distance R 2 from the center if the field at a distance 2R from the center is E A E B E 2 C 2E D 4E 3

If and u represent the permitivity and permeability of vacuum and and u represent the permitivity and permeability of medium the refractive index of the medium is given by THO A B C D daien Eoflo E E Eotto E V M EO Eo V again a grupal

Two particles carrying equal negative charge are kept fixed at x a and x a Another charged particle of mass m and charge of magnitude q is initially at rest at the origin and is constrained to move only along the X axis If the particle is displaced slightly in one direction it performs an SHM with time period T Then A The particle may be positively charged B The particle may be negatively charged C T2 000 m D T200 1 q

In figure current in the wire between a and b is neglect any resistance of connecting wires E r E r 1 E r 3 3E 4r b E r a BIN 2 5E 4r 4 E 2r