Physics Questions

The motion of a charged particle can be used to distinguish between a magnetic field and electric field in a certain region by firing the charge 1 Perpendicular to the field 2 Parallel to the field 3 From opposite directions 4 With different speeds

A bar magnet of magnetic moment 4 A m2 is placed along diagonal of a square in x z plane with its center at orig The magnetic field at a distance 1 m on y axis in tesla is 10 4 x 10 7 4 x 10 2 8

Given Potential difference V 8 0 5 V and current I 2 0 2 A The value of resistance R in Q is Question Type Single Correct Type 1 2 3 4 4 16 25 4 6 25 4 10 4 8

30 The slit in a double slit interference illuminated by a light of wavelength 600 nm A thin transparent sheet of thickness t is placed in front of one of the slits The number of fringe shifting is plotted across the refractive index u of the sheet as given The value of t is N No of fringe shifted 60 50 40 30 20 10 0 25 0 50 0 75 1 00 1 25 1 50 1 75 2 00 1 2 4 m 2 24 m 3 4 8 m

For two resestors R and R connected in parallel if R 30 1 2 and R 60 2 2 The percentage error in the measurement of equivalent resistance is 1 3 33 3 6 67 2 33 3 4 9 that is true

Carbon resistor has resistance specified by three bands having colour red yellow and black If this resistor is cut into two pieces of equal length then the new colour code of each one will be Neglect tolerance of 4th band Brown Red Black Red Orange Black White Blue Black O Black Blue Black

3 In the pair production process a y ray photon creates an electron positron pair If the total kinetic energy of electron and positron is 0 78 MeV then the energy of y ray photon is 1 1 80 MeV 2 1 10 MeV 3 1 01 MeV 4 1 27 MeV

Magnetic field Bo exists perpendicular inwards The resistance of the loop is R When the switch is made closed the current induced in the circuit is x x X X X X A X X X Bolv R Zero 38 v R 2B v R X R X X X x X X B C x X Bo X

A proton a deutron and an x particle accelerated through the same potential difference enter a region of uniform magnetic field moving at right angles to it What is the ratio of their kinetic energy 1 1 1 2 2 2 2 1 3 1 2 1 1 C A

A uniform disc of radius R and mass m lies on a smooth horizontal plane A ring of mass 2m and radius R 2 spinning with angular velocity wo is carefully lowered onto the disc such that centre of disc and centre of the ring coincide The coefficient of friction between them is Then which of the following is INCORRECT A The time when both disc and ring spin with the same angular velocity is R R B The time when both disc and ring spin with the same angular velocity is 2 g C The final angular velocity of disc becomes D The final angular velocity of ring becomes o 2 4 g 2

The two coils of self inductance 4 H and 4 H are wound on the same iron core The coefficient of mutual inducta for them may be 4 H 10 H 20 H 64 H

The magnetic susceptibility of a substance at room temperature is 0 0002 The susceptibility when the temperature increased by 2 C will be 0 0001 0 0002 0 0002 0 0005

A bar magnet and a wooden bar identical in dimension and mass are released from same height to fall under gra passing through multiple rings of conducting material Time taken by bar magnet is T and by wooden bar is T T which is possible out of given options T T T T T T None of these

During fusion reaction the device in which magnetic field is used to confine the plasma is called 1 Breeder reactor 2 Moderator 3 Tokamak 4 Geiger Nuttal counter

20 A wall has two layers A and B each made of different materials Both the layers have the same thickness The thermal conductivity of the material of A is twice that of B Under thermal equilibrium the temperature difference across the wall is 36 C The temperature difference across the layer A is A 6 C C 18 C B 12 C D 24 C 1

Question No The coercivity for a certain permanent magnet is 4 0 x 104 A m This magnet is placed inside a long solenoid of 40 turns cm and a current is passed in the solenoid to demagnetize it completely Find the current 10 A 20 A 30 A 5 A

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A steel wire of cross sectional area 0 5 mm is held between two fixed supports If the wire is just taut at 20 C determine the tension in N when the temperature falls to 0 C Coefficient of linear expe 1 2 x 10 5 C and its Young s modulus is 2 0 x 10 N m

35 In the given circuit switch is clos After a long time the iron rod is withdrawn from the inductor L Then the bulb Iron Rod 70000 L tham S B 1 Glows with same brightness 2 Glows more brightly 3 Gets dimmer 4 Stops glowing R

A body performs S H M due to force F with time period 0 8 s If force is changed to F it executes S H M with time period 0 6 s Now both the forces act simultaneously in the same direction on the same body New periodic time is A B C 0 48 s 0 24 s 0 12 s

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Figure shows a smooth horizontal table in x y plane between two identical fixed walls Two identical springs are connected to the small ball The length of the springs in the free state is The ball is shifted slightly from the equilibrium position in two different ways once along the axis OX and second along the y axis and it begins to perform vibrations The time period for these motions is T and T respectively A Motion along x axis is simple harmonic B Motion along y axis is simple harmonic C T 2n A A B B C C D D m 2k D T 2 2k Y mi 000000 000000 k k X

Question No 19 There are two circular coils of equal areas and equal magnetic flux through them The resistances of the colls are in the ratio 1 2 If the magnetic flux through the coils is switched off then the ratio of the charges flown through the coils will be 2 1 1 3 4 1 1 6

56 The wavelength of radiation emitted when an electron jumps from the third to second orbit of hydrogen atom is The wavelength of radiation emitted for the electron jumps from the fourth to second orbit of hydrogen atom will be 2 3 27 20 201 27 42 5 52

2 An electron is 2000 times lighter than a proton Both are moving such that their matter waves have a length of 1 The ratio of their kinetic energy in approximation is A 1 1 B 1 2000 D 1 200 C 2000 1

A tunnel is dug along a chord of earth having length 3R where R is radius of Earth A small block is released in the tunnel from the surface of Earth The particle comes to rest at the centre of tunnel Find coefficient of friction between the block and the surface of tunnel Ignore the effect of rotation of Earth 3 1 74

28 In a Young s double slit experiment sources of equal intensities are used Distance between slits is d and wavelength of light used is 2 2 d Angular separation of nearest points on either side of central maximum where intensities become half of the maximum value is 1 2 3 2 2d 2 4d

An electromagnetic wave of intensity 30 W m2 is incident on a surface of area 2 m If the surface is per absorbing then the amount of momentum transferred to the surface in 10s will be 2 x 10 6 kg m s 2 x 106 kg m s 4 x 10 9 kg m s 10 8 kg m s

t A thin ring of radius R metre has charge q coulomb uniformly spread on it The ring rotates about its axis with a constant frequency f revolution s The value of magnetic field in tesla at the centre of the ring is 1 2 3 Hogf 2mR Pog 2fR 4 Moq 2 fR Hogf 2R Al their planes at right angles to each other

7 If E is the amount of energy released radioactive element having mass number A undergoes alpha decay then the velocity of alpha particle is 1 3 2Q VA 4 A 4 E 2 4 2 A 4 E V Ama 2AE

27 In the following common emitter circuit if 100 VCE 7V VBE Negligible R 2 ko then I Ra ww B Rc E A 0 01 mA B 0 04 mA C 0 02 mA 15 V

The net charge in a current carrying wire is zero still magnetic field exerts a force on it because a magnetic field exerts force on 1 Stationary charge 2 Moving charge 3 A positive charge only 4 A negative charge only

1 An electron having kinetic energy ko collides with a hydrogen atom in the ground state This collision will be elastic if 1 3 4 eV k 10 2 eV 2 k 10 2 eV 3 k 10 2 eV k 10 2 eV

Zero Marks In all othe 300 identical galvanic cells each of internal resistance 90 are arranged as several in series groups of cells connected in parallel The arrangement has been laid out so that power output in an externally connected resistance of value 160 is maximum If n number of cells are connected in every series group that form parallel combination then find value of n HF 1 E E I E n 4 wwwwww R 16

A parallel plate capacitor with circular plates of radius R is being charged with a current as shown in the figure At R and R is given by instant shown the displacement current between the places enclosed between T O O i 15 16

1 Two protons each having kinetic energy K move towards each other from infinitely large separation Assuming a proton to be a sphere having radius equal to 1 fermi the minimum value of K for which the protons are able to touch each other is 1 360 keV 2 180 keV 3 720 keV 4 1440 keV

2 Consider the situation shown in figure The wire AB is slide on the fixed rails with constant velocity v If the wire AB is replaced by a semicircular wire the magnitude of the induced current will X X X X X X V X X X X X B X A increase B remain the same C decrease D increase or decrease depending on whether the semicircle bulges towards the y from it

A solenoid has an inductance of 10 henry and a resistance of 2 Q It is connected to a 10 V battery Time taken for t magnetic energy to reach 1 4 th of its maximum value is approximately C 2s 8s 3 5 s 2 5 s

Question The magnitude of emf induced in a 2 mH inductor in which the current changes from 8 A to 6 A in 10 sece 2 x 10 6 V 8 x 10 6 V 4 V 8V

Two wires are of same length and same area of cross section If first wire has resistivity p and temperature coefficient of resistance a but second wire has resistivity p and temperature coefficient of resistance a Their series equivalent resistance is independent of small temperature changes Then a a 0

120 The number N of scattered a par versus scattering angle 0 graph for a particle scattering experiment obtained by Geiger and Marsden is best represented by NA 1 3 V NA 2 4 V NA

A ballon start rising from the surface of the earth The ascent rate is constant and is equal to vo Due to the wind the balloon gathered the horizontal velocity component V ay where a is constant and y is the height of ascent Find the horizontal drift of the ballon x y

A thin bar magnet of length 24 and magnetic moment M is bent at the mid point so that the angle between the two halves is 60 The new magnetic moment of the bar magnet will be O O O M 2 2M 8M 4M

Phy Section A This section contains 35 SINGLE CORRECT TYPF questions Each question has 4 Read More A bulb is first connected across a 10 V DC supply and then a 20 V DC supply The ratio of power dissipated in the two cases will be resistance is constant 01 2 01 4 02 3

Which of the following statements are true a Magnetic field is produced by moving electric charge b Magnetic poles are only mathematical assumptions having no real existence c A north pole is equivalent to a clockwise current and a south pole is equivalent to an anticlockwise curres d A bar magnet is equivalent to a long straight current carrying wire a b and c are correct a and b are correct b and d are correct a and c are correct

61 If mass of electron is equal to 1840 mass of proton then energy of y photon required for the pair production of an electron and positron is 1 Less than 1 01 MeV 2 Equal to 1 01 MeV 3 Greater than 1 01 MeV times the Less than or equal to 1 01 MeV E

The magnetic field due to a small bar magnet in equatorial position is B the magnitude of magnetic field at the sax distance at axial position will be O O 28 812 B 4B

In semiconductors at a room temperature A The valence band is partially empty and the conduction band is partially filled B The valence band is completely filled and the conduction band is partially filled C The valence band is completely filled D The conduction band is completely empty

9 Which of the following graphs may represent 125 the relation between the capillary rise h and the radius r of the capillary h d W b a C A a B b r C C D d 12

Question No In a bar magnet angle between the magnetic axis and magnetic moment is choose the best possible answ OO 0 60 90 120