Basic Physics Questions and Answers

Q A bunch of bananas hangs from the end of a rope that passes over a light frictionless pulley A monkey of mass equal to the mass of the bananas hangs from the other end of the rope The monkey and the bananas are initially balanced and at rest Now the monkey starts to climb up the rope moving away from the ground with speed v What happens to the bananas A They move downward at speed v B They remain stationary C They move up at speed 1 2 v D They move up at speed v By Prasha

2 Suppose that u lu lu3 is an orthogonal basis for a three dimensional Hilbert s space A system is in the state given by 14 lu i 5124 Determine if this state is normalized 7 15 12 11 33 23

A 100 W bulb B and two 60 W bulbs B and B3 are connected to a 220 V source as shown in 1 2 2 Figure Now P P and P3 are the output powers of the bulbs B B and B respectively Then 2 3 B 1 P P P 2 3 P P P3 2 B 220V B 2 P P P3 4 P P P 3 2

When an alternating voltage E E sin oot is applied to a circuit a current I 1 sin cot flows through it The average power dissipated in the circuit is a E c EL 2 rms KIN b EI d 00 Zero 13

A negatively charged object X is repelled by another charged object Y However an object Z is attracted to object Y Which of the following is the most possibility for the object Z a positively charged only b negatively charged only c neutral or positively charged d neutral or negatively charged

21 The voltage across a resistor an inductor and a capacitor connected 8 32 series to an ac source are 20 V 15 V and 30 V respectively The resultant voltage in the circuit is a c 25 V b d 20 V 65 V

Passage 2 Using the following passage sovle Q 69 70 A block of mass m is released from a height h along a smoo track as shown in the figure a mg 69 Determine the force exerted on the block by the track point 2 where radius of curvature is r mg c 2 c m 2gh r m 2gh r M 2 h h 3 b 2mg d mg 70 Determine the minimum safe value of radius of curvats point 3 so that the block does not fly off the track a h h b 2 h h m 2gh 5 d m gh 5 2 h h 3

23 Acceleration of a body is given by the equation a 4 3v m s Speed v is in m s and t is in second If initial velocity is zero then terminal velocity of the 19 o body is 1 4 m s 3 4 m s 3 2 m s 4 4 Infinite

A square plate may either rotate in x z plane about point A or may rotate by falling towards x y plane If I and 1 are moment of inertias in the two cases respectively Find the correct option 2 D a I M1 c 1 1 5 4 ZA C B X b 1 1 2 d 1 1 1 2

Read the given paragraph X Y and Z are three methods of waste management X requires action of biological agents whereas Y and Z are chemical processes Both X and Y reduce the waste volume whereas Z makes the waste reusable Which of the following is incorrect regarding X Y and Z AX enriches the soil with nutrients and helps in recycling of matter between livin organisms and their environment BY generates gases and heat energy and is best suited for disposing toxic waste Z increases the demand and supply of fresh raw material and causes air and water pollution DSaprophytes and getritivores play a major role in X Ctrl

The x and y co ordinates of a particle at any time are given by x 2t 5 and y 72 where x and y are in metre and it is in second Velocity of the particle at t 2s will be Only One Correct Answer A 10i 73 m s B 24i 14 m s

b Calculate all voltage drops and currents in the circuit given below and complete with arrows for current direction and polarity markings for voltage polarity Then calculate the overall voltage gain of this amplifier circuit Av both as a ratio and as a figure in units of decibels dB V 22 k2 47 k R ww R V 3 2 volts

In the system shown m m System is held at rest by thread BC Just after lower thread is burnt wwwwww m A Bm Bumt C Acceleration of m is upwards Magnitude of acceleration of both blocks will be M M M m g Acceleration of m will be equal to zero

A constant current I flows in a strip line conductor resistivity of which increases monotonically in the direction of the current flow If resistivities at cross sections A and B are PA and PB find excess charge accumulated in the section AB Permittivity of free space is and relative permittivity of material of the strip is everywhere in the strip a PB PA I c 1 PB PA I b PB PA I d 1 PB PA I

An infinitely long straight wire carries a current i 1 amp A rectangular current loop placed in the san plane of shown dimensions carries a current i 1 amp anticlockwise Magnitude of net force on t loop is found to be B Find value of B 4x i 1 2a TE iz 2a 2a

The work done by the frictional force on a pencil in drawing a complete circle of radius 1 metre on the surface by a pencil of negligible mass with a normal pressing force N 5 N 0 5 is 1 4J 2 3 J 4 5 J 131

spts An electron traveling with a total relativistic energy of 7 GeV collides with a positron that travels in th opposite direction with a total relativistic energy of 4 GeV The electron and positron annihilate an produce the Y 4S resonance Upsilon What is the mass in GeV e and the speed of the Y 48 resonance Hint For this problem it is a very good approximation to treat the electron and positro as massless

250 17 250 X 10 cm 10 cm Figure also shows variation of potential between planes A negative charged particle carrying a charge q 1 6 10 1 C and having mass m 16 10 31 kg is released from rest at x 10 cm determine time taken in ns by particle to strike the other plane Neglect relativistic considerations eu faya Rada ct if g 1 6 10 1 Cu fy y 31 16 x 107 kg Ac x 10 cm ghazm d a agaa cha ay ny qua Ay

100 g of water at 25 C is poured into an insulating cup 50g of ice at 0 C is added to the water The water is stirred until the temperature of the water has fallen to 0 C 18 g of ice remains unmelted The specific heat capacity of water is 4 2J g C Which value does this experiment give for the specific latent heat of fusion of ice

Problem 1 50 points Analytically determine the linear displacement of the piston in th compressor linkage shown in Figure as the 55 mm crank is rotated from its current positic 20 clockwise Use analytical method Drawing is necessary but don t have to dra with proper scale 55 mm 60 crank 120 mm piston

on is connected to an external power supply the junction is said to be forward options Marks 1 The depletion width junction OPTIONS widens remains same shrinks in the forward bias which results in having a majority flow across th widen and shrink alternatively

Newton s rings are formed with a source of light containing two et elengths and 22 If mth order dark ring due to coincides with the th order dark ring due to 2 prove that the radius of the mth dark ring is equal to m ved surface 1 2 R 21 22 where R is the radius of curvature of the lower litounoriment with a light of wavelength 600 nm

a What do you understand by wave particle duality Describe with diagram an experiment which verifies de Broglie s hypothesis he Ek Ek 2moc b Prove that de Broglie wave length for a particle of rest mass mo and kinetic energy E is What will be the de Broglie wavelength for a free electron with energy 1 MeV c Find the velocity of an electron whose de Broglie wavelength is equal to its Compton wavelength

hr mir When two displacements represented by y a sin wt and y b cos wt are superimposed the motion is Simple harmonic with amplitude a b 2 Not a simple harmonic

Consider an electron with a kinetic energy of 2 8 eV incident on a step potential function of height 3 5 eV Determine the relative probability of finding the electron at a distance a 5 beyond the barrier b 15 beyond the barrier and c 40 beyond the barrier compared with the probability of finding the incident particle at the barrier edge

Problem 1 Two earth satellites A and B each of mass m are to be launched into circular orbits above earth s surface at altitudes 6400 km and 1 92 104 km respectively The radius of the Earth is 6400 km Find the ratio of their potential energies Ratio A 2 200 1 11 1 GMem 6400 6400 G Mem 6400 1 92X10 GM m 12800 P E GM m 12800 G Mem r 11 G Mom Reth 1 92 X10 6400 12800 2 1 2

17 The arm PQ of a rectangular conductor is moving from x 0 tox 2b outwards and then inwards from x 2b to x 0 as shown in the figure A uniform magnetic field perpendicular to the plane is acting from x 0 to x b Identify the graph showing the variation of different quantities with distance x 0 x b x 2b b 2b b a A Power dissipated B Flux C EMF b A EMF B Power dissipated C Flux c A Flux B Power dissipated C EMF d A Flux B EMF C Power dissipated

35 180 Mark for Review A conducting square frame of side a and a long straight wire carrying current are located in the same plane as shown in the figure The frame moves to the right with a constant velocity V The emf induced in the frame will be proportional to 108 02 49 hr min V

A person whose mass is 100 kg travels from Earth to Mars in a spaceship Neglect all other objects in sky and take acceleration due to gravity on the surface of the Earth and Mars as 10 m s2 and 4 m s2 respectively Identify from the below figures the curve that fits best for the weight of the passenger as a function of time

13 A current of 5 A is passing through a non linear magnesium wire of cross section 0 04 m At every point the direction of current density is at an angle of 60 with the unit vector area of cross section The magnitude of electric field at every point of the conductor is Resistivity of magnesium p 44 x 10 8 22 m a 11 x 105 V m c 11 x 10 V m 1 1 b 11 x 107 V m d 11 x 102 V m 1

Two short bar magnets with pole strengths of 900 ab amp x cm and 100 ab amp x cm are placed with their axes in the same vertical lines with similar poles facing each other Each magnet has a length of 1 cm When the separation between the nearer poles is 1cm The weight of the upper magnet is supported by the repulsive force between the magnets If g is 100 cm sec then the mass of the upper magnet is A 100 g B 55 g C 77 5 g D 45 g

6 A steel block of 10 kg rests on a horizontal floor as shown When three iron cylinders are placed on it as shown the block and cylinders go down with an acceleration 0 2 m s2 The normal reaction R by the floor if mass of the iron cylinders are equal and of 20 kg each is N 2 Take g 10 ms and 0 2 3 2 77 a 0 2 ms

A uniform rod of length and mass M hinged at one end is released from vertical position as shown The acceleration of centre of mass of rod in horizontal direction when the rod is in horizontal position will be 0 0 3910 3g 3g 02

A satellite is moving around the earth in circular orbit The total energy of satellite is E and gravitational potential energy is U then E Find n Answer 0 01 02 03 04 05 06 07 8 09 00 01 02 03 04 05 06 07 8 09

In a physics lab the teacher decided to test the students ability to set up electrical circuits and asked them to set up the circuit shown in the figure Each student was given a combination of 3 resistors of 2 00 4 00 and 6 00 and 2 ideal batteries of 8 00 V and 12 0 V The teacher later wanted to assess the students work but she did not have enough time to examine each circuit connection Therefore she decided to use a voltmeter to measure the voltage between points c and d for each student s circuit What would be the voltmeter reading in case of correct connection A 1 36 V B 1 82 V C 3 00 V D 4 80 V www 2 00 8 00 V 120 V H 6 00 4 00 V

A wire of length L is hanging from a fixed support The length changes to L and L when masses M and M are suspended respectively from its free end Then L is equal to b LL d a c L 1 2 2 L M L M L M L M

7 a Establish relativistic energy momentum relation And hence show that the group velocity associated with a particle is essentially velocity of that particle b Why in case of moving electrons quantum mechanics is used while for moving car we use Newtoniar mechanics c Find the velocity of an electron whose de Broglie wavelength is equal to its Compton wavelength

7 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 ent puout bot ert 4 152 benuo st

Two objects of masses 1 kg and 3 kg are connected by a massless string passing over a fixed smooth pulley The acceleration of heavier mass with respect to the lighter mass is 1 kg 3 kg 294 O g 0 39 O

The ratio of the specific heats 9 7 in terms of degrees of freedom n is given by 0 1 1 2 1 0 0 1 1 O

22 Two identical cells whether joined together in series or in parallel give the same current when connected to external resistance of 2 2 Their internal resistance 1 22 3 1 5 ris 2 19 4 4 Q

A uniform rod of mass M and length hinged at one end is held in equilibrium by applying a constant force F at other end as shown in figure The system is in vertical plane Force exerted by hinge on the rod is F

d hours if it is rotating from east to west 17 If E M L and G denote energy mass angular momentum and gravitational constant respectively then which of the following is are having incorrect dimension for F L M G a Angle c Mass b Length d Energy

2 If arithmetic means are inserted between two sets of numbers a 2b and 2a b where a b e R Suppose that mth arithmetic means between these two sets of numbers is same then the ratio a b equals to b nm 1 n d n nm 1 a nm 1 m c m nm 1

The vessel shown in figure has two sections of area of cross section A and A A liquid of density p fills both the sections up to height h in each Neglecting atmospheric pressure Then which of the following statements is are correct Fr A X a The pressure at the base of the vessel is 2hpg b The force exerted by the liquid on the base of vessel is 2hpgA c The walls of the vessel at the level X exert a force hpg A A downwards on the liquid d The weight of the liquid in vessel is equal to 2h0gA

A light rod of length I is hanging inside a vehicle moving horizontally with acceleration g having a small mass attached at it s one end is free to rotate about an axis passing through the other end The minimum velocity given to the mass at its lowest position so that it can complete vertical motion is

Zero Marks 0 Negative Marks 2 In all other cases A monoatomic ideal gas of two moles is taken through a cyclic process starting from A as shown in figure AP V V V If none of the options is chosen i e the question is unanswered 0 BEN A MENA DE BE D I B T V VA The volume ratios are 2 and VA temperature T at A is 27 C Then a the temperature of the gas at point B is 600K b heat absorbed is process AB is 1500R c heat released in process DA is 750 9R d heat absorbed in process BC is 831 8R 4 If the

13 If the potential difference V applied across a conductor is increased to 2V with its temperature kept constant the drift velocity of the free electrons in a conductor will 1 iv remain the same become half of its previous value be double of its initial value become zero

Q 46 A circular coil of 20 turns and radius 10 cm is placed in a uniform magnetic field of 0 10 T normal to the plane of the coil If the current in the coil is 5 0 A The total force and toque on the coil will be a 10 N and 20 J b 0 N and 0 J c 0 N and 5 x 10 25 J d none of these

that substance is Read the following passage to answer the given questions based on it Choose the correct options Marks 2 The atomic packing fraction of lattice will be OPTIONS 6 3TT 8 2 6 9 O 3r 6