Basic Physics Questions and Answers

A cylinder of volume V 10 2 m made by non conducting walls contains 8 gm of He gas The cylinder is divided by a thin fixed membrane into two unequal parts Volume of the left compartment is V 3 and the right component has volume 2V 3 The left compartment has an installed electric heater Due to finite conductivity of the membrane heat passes from the left part into the right part Heat transfer rate through the membrane is 0 2 watt per AT 1 C temperature difference across the membrane Initially the heater is off and both the parts are in thermal and mechanical equilibrium The membrane can withstand maximum pressure difference of 103 Pa The heater starts supplying heat slowly the left compartment at its maximum possible power such that the membrane remains intact after long time of heating also Take R 25 3 J mol K Column Column II A For the left compartment B For the right compartment C For the whole cylinder D Through the membrane q s t 100001 Pressure of the system 1 Temperature of the system Rate of transfer of heat is 0 20 watt Rate of transfer of the heat is 0 06 watt Rate of transfer of heat is 0 12 watt Rate of change of internal energy is constant

A gas shows heating effect on sudden expansion It shows that A the gas is nobel B the gas is ideal C the inversion temperature of the gas is very low D its Vanders Waal s constant b is high

3 A null point is obtained when two resistors of resistance r each are connected in series and placed in the fourth arm of a Wheatstone bridge Now the resistance R of the third arm is kept fixed and r connected in parallel are placed in the fourth arm Then a null point is obtained only by interchanging the resistances P and Q of the first two arms Find the ratio of P and Q and also the value of r R

2 In a Wheatstone bridge a resistance S is fixed in fourth arm Keeping resistance R in third arm null condition is obtained Now if the resistances P and Q are inter changed resistance R has to be replaced by R to get the balance condition again Find the ratio of P and Q and LR R R R also the value of S

1 Two cells of emfs and are connected as shown in Fig 2 70 When a potentiometer is connected between A and B the balancing length of the potentiom eter wire is 3 00 m On connecting the same potentiometer between A and C the balancing length is 1 00 m Calcu late the ratio of 1 and 2 411 B 62 C

The half life of Bi2 0 is 5 days In what time 7 8 th part of the sample will decay Question Type Single Correct Type 1 2 3 4 Status 3 4 days 10 days 15 days 20 days Unattempted

A man in a boat crosses a river from point A If he rows perpendicular to the banks he reaches point C BC 120m in 10 min If the man heads at a certain angle a to the straight line AB AB is perpendicular to the banks against the current he reaches point B in 12 5 min Find the width of the river w the rowing velocity u the speed of the river current v and the angle a Assume the velocity of the boat relative to water to be constant and the same magnitude in both case u B A

A wwwww www 60 wwwww 100 wwww 2 www 45 B Fig 2 71 420 In the Fig 2 71 if a potential difference of 2 1 V is applied between the points A and B then what will be the cur rents through the resistances 40 and 45 30 mA 20 mA

A student crazed by final exams uses a force P of magnitude 81 N and angle 8 74 to push a 5 1 kg block across the ceiling of his room as in the figure If the coefficient of kinetic friction between the block and the ceiling is 0 43 what is the magnitude of the block s acceleration AP 18

9 The resistance of a potentiometer wire is 10 kn Its two ends are connected with a 200 V source of electricity If a voltmeter of resistance 5 kn is connected in parallel with one fourth of the wire then what will be the reading of the voltmeter 36 4 V

The distance between the positions of two null points obtained in a metre bridge wire of length 100 cm by interchanging a known resistance of 2 5 unknown resistance in the two gaps is 28 6 the value of the unknown resistance and an cm Find HS 11

In downward direction a ball is dropped it s initial velocity is zero and if thrown it s initial velocity is present it is not zero So two words drop and throw completely different meanings 11 51 PM

A cell of emf V volts and negligible internal resistance is connected across a potentiometer whose sliding con tact is placed exactly at the middle A voltmeter is con nected between the sliding contact and one fixed end of the potentiometer If it is assumed that the resis tance of the voltmeter is not very high compared with the resistance of the potentiometer what voltage will the voltmeter show higher than or less than Justify V your answer

In the left gap of a metre bridge there is a coil of copper and in the right gap there is a fixed resistance If the coil of copper is dipped in ice the balance point is obtained at 41 2 cm of the bridge wire Next the coil is taken off from ice and placed in a container of hot water Now the balance point is shifted by a distance 8 1 cm towards right What is the temperature of hot water Temperature coefficient of resistance of 125 x 10 4 C 1 18

3 8 s Two balls A and B of same masses are thrown from the top of the building A thrown upwards and B thrown downwards with same speed Then on reaching the ground the velocity of ball 1 A is more than that of B 2 B is more than that of At at 94 0 42 6 4 2450 3 A is same as that of B wootly double than that of A4 64 6 9 42 59 60

1 AIPMT 2007 A 5 watt source emits monochromatic light of wavelength 5000 A When placed 0 5 m away it liberates photoelectrons from a photosensitive metallic surface When the source is moved to a 9 The figure shows a plot of pl distance of 1 0 m the number of photo electrons liberated will 1 be reduced by a factor of 2 2 be reduced by a factor of 4 3 be reduced by a factor of 8 4 be reduced by a factor of 16 MP0066 is 9 mW The number of photons arrivir on the average at a target irradiated b 1 3 x 10 MP0068 1014 Hair 3 3x106 2 9x15 4 9x three different radiations Whis is a correct statement phot Retarding

A circular disc of mass m and radius R is set into motion on a horizontal floor with a linear speed v in the forward direction and an V angular speed in clockwise direction as shown in figure 3R Find the magnitude of the total angular momentum of the disc about the axis perpendicular to the plane of disc and passing through the bottom most point O of the disc and fixed to the ground

7 As shown in figure a dust particle with mass m 5 0 x 10 kg and charge q 2 0 nC starts from rest at point a and moves in a straight line to point b What is its speed v at point b 1 26 ms 3 46 ms 3 0 nC 1 0 cm a 2 34 ms 4 14 ms 1 0 cm 3 0 n b 1 0 cm

A moldable blob of mater of mass M is to be situated between the planes z 0 and z 1 see figure so that the moment of inertia around z axis be as small as possible What shape of a sold object should the blob take A solid cylinder C solid sphere Z 1 z 0 z axis B solid obtained by rotating parabola D solid cone

12 An ink dot on a sheet of paper is viewed from above a dis tance of 50cm By what distance would the ink dot appear to be raised if it is viewed through a glass slab of thickness 15cm held parallel to the paper Given refractive index of glass 1 5 5 cm

A rigid uniform bar is pivoted or hinged at its lower end on a wall and makes an angle of 30 with the vertical To the upper end of the bar is attached a horizontal rope vhose other end is attached to the wall A load of 2000 N is hung from the upper end of the bar If the bar is 6 6 m long and has weight of 1500 N find a the tension in the ope and b the vertical and horizontal force exerted by the wall on the pivot at the ower end of the bar

13 Refractive index of glass is 1 5 and that of water is 1 33 Will total internal reflection of a ray of light take place from glass to water If total internal reflection takes place what will be the critical angle yes 60

A metal cube of 300 g at 90 C is dropped into a copper container of mass 200 g containing water weighing 180 g at 50 C The final temperature reached is 60 C Calculate the specific heat capacity of the metal cube Specific heat capacity of copper is 0 4 Jg 1 C 1 and that of water is 4 2 J g 1 C 1

A uniform rod string AC End A of the string is fixed to the ceiling and the end B of the rod is on a smooth horizontal surface B is exactly below point A and length AB is b a b 2a The system is released from rest and the rod begins to slide Find the speed of the centre of the rod when the string becomes vertical 2 B 2 g

A ladder AB is supported by a smooth vertical wall and rough horizontal floor as shown A boy starts moving from A to B slowly The ladder remains at rest the pick up the correct statement s Smooth Wall Rough floor A Magnitude of normal reaction by wall on ladder at point B will increase B Magnitude of normal reaction by wall on ladder at point A will decrease C Magnitude of normal reaction by floor on ladder at point A will remain unchanged D Magnitude of friction force by floor on ladder at point A will remain Increase

To a driver going east in a car with a velocity of 40 kmh a bus appears to move towards north with a velocity of 40 3 km h What is the actual velocity and direction of motion of the bus 3

1 If force F length L and time T are chosen as the fundamental quantities then what would be the dimensional formula for density 2

Read Only You can t save changes to this file Qs 8 A thin flexible uniform chain of mass and length I is suspended so that its lower end just touches a smooth inelastic plane inclined at 45 When it is released find the force exerted by the chain on the plane at any instant QE a c 3mg 1 2 21 mg 21 b d 3mg t EL mg 2 4L 45

A ladder is at rest with its upper end against a wall and its lower end on the ground A worker about to climb it When is it more likely to slip a Before the worker is on it b When the worker is on the lowest rung c When the worker is halfway up the ladder d When the worker is on the top rung

The two slits of double slit experiment were moved symmetrically apart with small relative velocity v and the distance between screen and mid point of slits is fixed and equal to D Consider a point P on the screen at a distance x from central maxima then x D A Rate of change of number of fringes between central maxima and point P changes with XV AD respect to time is B Number of fringes contained between central maxima and point P increases with time C Fringe width decreases as time passes D Maximas are moving closer to each other

Four balls each of radius 10 cm and mass 1 kg 2 kg 3 kg and 4 kg are attached to the periphery of the massless plate of radius 1 m 210 cm dificha wa 1 kg 2 kg 3 kg 4 kg ilha de palice 1 m af AR CATA 4 kg 1 kg B 10 04 kg m 1 m 2 kg 3 kg What is moment of inertia of the system about the centre of the plate CHITTA CRY FICPIC PIPDAK GYOI GNK 201 A 12 04 kg m C 11 50 kg m D 5 04 kg m

9 A given charge situated at a certain distance from a short electric dipole in the end on position experience a force F If the distance of the charge is doubled the force acting on the charge will be 1 2F 2 2

3 1023 m s The electric field at a point on the equatorial plane at a distance r from the centre of a dipole having dipole moment p is given by r separation of two charges forming the dipole Eo permittivity of free space NEET 2020 Phase 2 1 2 3 E L P 3 4 or P 4 or 3 2P 3 4 or P

3 4 10 Nm 1 A charge q is placed at the centre of the open end of a cylindrical vessel The flux of the electric field through the surface of the vessel is 1 Zero 2 q Eo 2a

5 Due to effect of interfernce floating oil layer in water is visible coloured due to observation of this the thickness of oil layer should be 1 10 nm 2 0 1 m 3 1 mm event 4 10 mm WO0035

0 A particular straight line passes through origin and a point whose abscissa is double of ordinate of the point The equation of such straight line is 1 y X 2 3 y 4x 2 y 2x 4 y X 4

11 In a parallel circuit as shown in figure if IR IL Ic and I represent the rms values of current flowing through resistor inductor capacitor and the source then choose the appropriate correct answer 44900 a I IR IL Ic c I or I may be greater than I IR IL Ic R vooo C HH ad bodi b I IR IL Ic d None of these

A bird is flying to and fro between two cars A and B moving towards each other on a straight road with speed 18 km h and 36 km h respectively The bird starts moving from car A towards car E when the two cars were separated by 54 km Th displacement of bird till two cars meet is Negler dimensions of car 1 54 km 18 km 3 36 km 6

2 A bird is flying to and fro between two cars A ar B moving towards each other on a straight ro with speed 18 km h and 36 km h respective The bird starts moving from car A towards car when the two cars were separated by 54 km T displacement of bird till two cars meet is Negl dimensions of car 1 54 km 218 km 3 36 km 4 Data insufficient

In the figure magnetic field points into the plane of paper and the conducting rod of length lis moving in this field such that the lowest point has a velocity v and the topmost point has the velocity v U The emf induced is given by a Bul c B v v l X X X X X X V2 X X X X V X X X X X X b Bugl d B v v 1

The sum of magnitudes of two forces acting at a point in 16 N If their resultant is norm 7 24 smaller force and has magnitude of 8N 1 forces are 1 3 N 13 N 2 4 N 12 N 3 6 N 10 N 4 7 N 9 N

28 In figure the switch is in the position 1 for a long time then the switch is shifted to position 2 at t 0 At this instant the value of i and in are 1 2 a ERD 0 E E ET 0000 R b iz E E R R d None of these

Q 47 Two fixed frictionless inclined planes making an angle 30 and 60 with the horizontal are shown in the figure Two blocks A and B are placed on the two planes What is the relative acceleration of A with respect to B 60 B 30 1 4 9 ms 2 in horizontal direction 2 9 8 ms 2 in vertical direction 3 Zero 4 4 9 ms 2 in vertical direction

24 If random error in an experiment for 10 observations is e then random error in experiment for 60 observations will be 1 e 3 6 e L 2 4 6 e 36

23 A balloon carrying a stone is moving upward with constant speed 10 m s When balloon is at heigh 75 m the stone is dropped The time taken b is the stone to reach the ground after release g 10 m s2 1 4 s 3 5 s 2 15 s 4 6 s

A solid ball of mass m and radius r spinning with angular velocity falls on a horizontal slab of mass M with rough upper surface coefficient of friction and smooth lower surface Immediately after collision the normal component of velocity of the ball remains half of its value just before collision and it stops spinning Find the velocity of the sphere in horizontal direction immediately after the impact given Rw 5 M

31 A ball A is thrown up vertically with a speed u and at the same instant another ball B is released from a height h At time tt to B is LEITU 10 2h g 1 speed of A relative 2 2u 2

2 46 Two polaroids are placed in the path of an unpolarized beam of intensity Io such that no light is emitted from the second polaroid If a third polaroid whose polarization axis makes an angle with the polarization axis of first polaroid is placed between these polaroids the intensity of light emerging from the last polaroid will be 2 4 20 1 8 20 20 10 3 4 1 A

27 particle is projected at an angle 30 with the horizontal with speed 20 m s How high will it strike a wall 8 3 m away from point of projection g 10 m s 1 5 m 3 24 m 2 4 8 m 4 96 m

33 In the following question a statement of assertion A is followed by a statement of reason R A Pascal s law is the working principle of hydraulic lift Thrust Area 1 A is true and R is true and R is the correct explanation of A 2 A and R are true but R is not the correct explanation of A R Pressure 3 A is true R is false 4 A is false R is true