Basic Physics Questions and Answers

On increasing temperature and mixing impurities the elasticity of a materia 1 Increases Increases 3 Increases Decreases 2 Decreases Decreases 4 Decreases Increases Water is moving with a speed of 3 5ms through a pipe with a cross sectio 2 2cm The water gradually descends 9 66 m as the pipe increase in area to The speed of flow at lower level is

Technician A says modern torque converters are serviceable if an internal component fails Technician B says that modern torque converters are designed to be replaced as a complete assembly if an internal component fails Which technician is correct Technician A Technician B Both technicians A and B Neither technician A nor B

Young s double slit experiment is first performed in air and then in a medium other than air It is found that 8th bright fringe in the medium lies where 5th dark fringe lies in air The refractive index of the medium is nearly A B C 1 78 1 25 1 59

A particle move along the parabolic path X y 2y 2 in such a way that the y component of velocity vector remain 5 m s during the motion The magnitude of the acceleration of the particle is 1 50 m s 2 100 m s 3 10 2 m s 4 0 1 m s

6 Three vectors P Q and R are shown in the figure Let S be any point on the vector R The distance between the point P and S is b R The general relation among vectors P Q and S is JEE Advanced 2017 P b R Q a S b 1 P bQ c S 1 b P b Q S R Q P X b S 1 6 P bQ d S 1 b P bQ

Two vectors and b add up to a vector c When vector is made 3 times as long and vector b is doubled in length without changing their directions then it is found that vector c is also doubled in length without change in direction Then which of the following is true J K CET 2012 a All three vectors must be parallel b b and must be parallel to each other but a need not be parallel to b and c c a and b must be perpendicular to each other d It is impossible for three non zero vectors a b and c to have the property stated above

If B C and the angle between C 120 then O O Must be equal to must be less than A B may be equal to A B Must be greater than A B A B and B is Clear Resp

1 A pulse of light of duration 100 ns is absorbed completely by a small object initially at rest Power of the pulse is 30 mW and the speed of light is x 108 ms The final momentum of the object is 1 a 0 3 x 10 17 kg ms b 1 0 10 7kgms c 3 0 x 10 7kg ms d 9 0x 10 17 kgms 1 JEE Adv 13

A point like body has velocity and acceleration at initial point as shown in figure Time after which velocity reaches at minimum value V 24 m s 143 a 6 m s 4 sec 2 3 2 sec 3 2 4 sec 4 3 sec

D Assume that a police siren emits sound of wavelength 2 cm If an observer moving with a speed 20 m s approaches a stationary police jeep which with its siren switched on then the wavelength observed by the observer will be 1 0 5 m 2 1 cm 4 2 cm

7 Two vectors A and B have components A Ay A and B By B respectively If A B 0 then Odisha JEE 2010 a A B A B A B b Ax B A B A B 2 c A Bx A B A B d A B A B A B

The velocities of sound at the same pressure in 9 two monoatomic gases of densities p and p are V and v respectively If 4 then the P2 value of is 0 2 3 2 A rocket is fired from earth s surface with a 10 at V 1 2 3 4 que tu ara af in 2 fe V m 1 P2 3 2 1 2 ne year of dy 2 Refer 4 4 4

Question No 1 Two rods of equal length AC and BC are freely joined at C C is movable Two ends A and B are pulled with speeds 2 m s and 3 m respectively as shown in the figure at a particular instant Take l 3m 0 3 The speed of the point C at this instant is 1 The speed of the point C at this instant is 2 m s 5 The angular velocity of the left rod is 3 3 m s rad s 5 The angular velocity of the right rod is 3 3 rad s 2 m s A 1 60 1 60 B 3 m s

3 A small telescope has an objective lens of focal length 140 cm and an eye piece of focal length 5 cm What is the magnifying power of the telescope for viewing distant objects when a The telescope is in normal adjustment final image at infinity b The telescope is in adjustment for least distance of distinct vision

CENTRE A block of mass M is placed on a horizontal smooth table It is attached to an ideal spring of force constant k as shown The free end of the spring is pulled at a constant speed u Find the maximum extension x in the spring during the subsequent motion M k 4 Aakash MedicalT JEE Founda

Let the angle between two nonzero vectors A and B be 120 and resultant be C a C must be equal to A BI b C must be less than A BI c C must be greater than A BI d C may be equal to be equal to A BI

5 Consider a uniform electric field E 3 x 10 i N C a What is the flux of this field through a square of 10 cm on a side whose plane is parallel to the yz plane b What is the flux through the same square if the normal to its plane makes an angle of 60 with the x axis c What is the net flux through a cube of side 20 cm oriented so that the faces are parallel to the coordinate planes d If the flux through the cube mentioned above has no net flux through itself can you conclude that there is no charge inside the cube Why or why not

A wire of length 1 6 00 0 06 cm and radius r 0 500 0 005 cm has mass m 0 300 0 003 g Maximum percentage error in density and quantity contributing to maximum percentage error is O O 4 radius 2 radius 4 length Clear Respons

Bonus Question 1 A monkey is sitting on a wood plate attached to a rope whose other end is passed over a tree branch as shown in the figure The monkey holds the rope and tries to pull it down The combined mass of the monkey and the wood plate is 125 kg a What is the minimum force the monkey has to apply to lift off the ground in N m 125kq 9 9 8mls M 2T mg 2T 125 9 8 T 613 5 Not a b cal Lal M A 382 82 B 447 90 C 524 04 D 613 12 E 717 36 F 839 31 G 981 99 H 1148 93 LEVOLEZ MARGARE HAC 12 A OHATE b Now assume there is a second monkey standing on the ground and pulling down the rope by himself What is the minimum force this second monkey has to apply to lift the first monkey on the wood plate off the ground in N A 408 58 B 478 04 C 559 31 D 654 39 E 765 63 F 895 79 G 1048 08 H 1226 25

Two vectors A and B lie in a plane Another vector lies outside this plane The resultant A B C of these three vectors A can be zero C lies in the plane of A B D lies in the plane of A B B cannot be zero

A 4m long rod AB slides down the plane with VA 4 m s to the left and aA 5 m s to the right The value of 0 at given instant is 30 cos 15 0 965 sin 15 0 258 Choose the correct statement s 4m 135 a 0 The angular velocity w of the rod at given instant of time is 0 73 rad sec The angular velocity w of the rod at given instant of time is 0 23 rad sec The angular acceleration a of the rod at given instant of time is 0 234 rad sec The angular acceleration a of the rod at given instant of time is 0 77 rad sec B

A parallel plate capacitor with a Porcelain dielectric has a capacitance of 87 3 nF If the Porcelain is replaced by pyrex glass the capacitance will now be nF Dielectric constants for various materials at 25 C Material Vacuum Air at 1 0 atm Polystyrene Paper Pyrex glass Porcelain Nerve membrane Silicon Ethanol Water Dielectric constant k 1 0 1 0005 2 6 3 5 4 7 6 5 7 0 12 0 25 0 78 5

Just like in reflection of light the reflected r ay takes a path keeping the angle of reflecti on same as the angle of incidence with the normal similarly if a small ball hits a polish ed hard surface at an angle with the normal at the point it hits will it follow a path makin g the same angle with the normal as a refle cted ray when it bounces back

3 Two parallel infinite line charge having equal and opposite charge density separated by a distance 4 cm produce a field 18 104 N C midway between them The magnitude of linear charge density of line charges will be 1 0 2 Cm 2 0 1 Cm 4 0 5 Cm 1 3 0 15 Cm

1 2 2 3 3 3 2 4 2 A thin plano convex lens acts like a concave 43 mirror of radius of curvature 20 cm when its plane surface is silvered The radius curvature of the curved surface if index of refraction of its material is 1 5 will be 1 10 x 10 m 3 10 x 10 m 2 10 10 m 4 10 10 m X An astronomical talascona har an objective lang 1 2 2 3 20 cm if 31 5 ari 3 3 2 1 10 x 10 m 3 10 x 102m 12 m a zit de 4 2 dan af aastal faal 2 10 x 10 m 4 10 x 10 m s G AI L

question has 4 choices 1 2 3 and 4 out of which only one is A parallel plate capacitor is filled with two dielectrics as shown in the diagram The area of plates is A and the distance between the plates is d If the thickness of each dielectric slab is d 2 and the dielectric constants are K and K then the net capacitance is K K 2 AKK d K K O BA A K K Read More 80 A K K 2d

1 Consider a rectangular rod AB CD in which CD is a movable arm is placed in the magnetic field to the plane of the paper Let us ass ume length of the rod AB I and x is the distance moving with the v elocity v Derrive the expression f or emf and current in the circuit

5 A metallic ring with a cut is held horizontally and a magnet is allowed to fall vertically through the ring then the acceleration of this magnet is 1 Equal to g 2 More than g 3 Less than g news of AY ometimes loss and sometimes more than T

A gas is compressed at a constant pressure of 50 N m from a volume of 10 m to a volume of 8 m Energy of 200 J is then added to the gas by heating Its internal energy is 1 Increases by 300 J 2 Increases by 200 J 3 Increases by 400 J 4 Increases by 100 J

SAMPLE PROBLEM 4 5 The Moon revolves about the Earth making a complete revolution in 27 3 days Assume that the orbit is circular and has a radius r 238 000 miles What is the magnitude of the gravitational force exerted on the Moon by the Earth Solution We have r 238 000 mi 3 82 x 10 m From Ap pendix C we find the mass of the Moon is m 7 36 x 1022 kg The time for one complete revolution called the period is T 27 3 d 2 36 106 s The speed of the Moon assumed constant is therefore V FME 2 r T The centripetal force is provided by the gravitational force on the Moon by the Earth Result my Speed of the moon Centripetal force I 1 m s N

ILLUSTRATION 4 5 A long copper wire carries a current of I ampere Calculate the magnetic flux per meter of the wire for a plane surface S inside the wire as shown in figure R 0 S Sol Consider an element of width dr at a distango u fr

A and B working together can complete a work in 12 days If they start the work together and after working for 3 days A leaves the work and B completes the remaining work in 15 days then the time taken by A to complete the whole work is 18 days 20 days 25 days 30 days

A semicircular conducting ring ABC of mass m 20 kg and radius r 4m is placed on a horizontal surface and a uniform magnetic field B 2 Tesla exists parallel t horizontal surface but perpendicular to the line AC Almost instantaneously a certain amount of charge is passed through it then it is found to jump to a height h 5m then find the amount of charged passed through the conductor is coulomb take g 10 m s C B

The strain in the upper wire when the whole system moves upwards with an acceleration of 2 ms2 will be given that area of cross section of each string is 0 5 mm and Y 2 x 10 1 Nm 2 x 10 4 4 x 10 4 3 kg T 2 kg

50 ml of 0 20 M solution of washing soda reacts with one of the acids in aqua regia One of the products is Chile saltpetre If the strength of the acid is 0 25 M what vol ume of it will be required to react with the above solu tion 2013 IJSO Stage II A 40 ml B 10 ml C 20 ml D 80 ml

If a coin lying at the bottom of a water filled bucket appears to be raised by a distance At then water is filled in the bucket upto a height Refractive index of water n 1 3 Atn Atn jons 2 At 1 Aff1 4 At 1 n

The cart shown accelerates along the track with a 2t 4 m s2 Its initial velocity is 3 m s At t 5s R 100 m 0 The magnitude of acceleration is 6 034 m s The angular position of go cart along the track is 0 0667 rad The position of go cart along the track is 6 67 m The total distance travelled along the track in 0 5 s interval is 28 3 m

4 A particle is executing SHM on a straight line A and B are two points at which its velocity is zero The particle is crossing certain point X AX XB at successive intervals of 1 2s and 3 6s with a speed of AX 4 m s The ratio is XB 1 3 2 2 1 3 2 C 2 4 2 1 2 1 2 1 2 1

36 In a hurdle race a runner has probability p of jumping over a specific hurdle In 5 trials if the runner succeeded 3 times then the conditional probability that the runner had succeeded in the first trial is 3 2 1 d None 5 5 5 a b C

3 3 x 108 4 0 5 10 Light of wavelength 5000A is incident on a 23 single slit such that first minima is formed at a distance 5 mm from the centre If the screen is placed 2 m away then find the width of slit 1 0 2 mm 3 0 4 mm 2 2 mm 4 4 mm 3 3 108 4 0 5 10 5000 de t far qven fafers fa 2 m fera 1 0 2 mm 3 0 4 mm fer af mm fer 2 2 mm 4 4 mm

A chain with mass density o kg m lies in a heap at the edge of a table One end of the chain initially sticks out an infinitesimal distance from the heap You grab this end and accelerate it downward with acceleration a Assume that there is no friction of the chain with itself as it unravels Choose the correct statement s 0 The force as a function of time that hand apply to the chain is at 0 The force as a function of time that hand apply to the chain is oat 3a g The value of a that makes force by hand to be zero is O The value of a that makes force by hand to be zero is zero

Question No 35 Single Correct A A Ratio of de Broglie wavelength of proton and deuteron is 1 4 Then ratio of their KE will be 32 1 8 1 64 1 16 1

4 All to above A prism shaped imaginary structure is given A 16 point charge is kept a given in figure Calculate electric flux passing through the prism 45 1 9 4 0 9 2 8E0 9 16 0 3 q 4 32 o Series of infinite charges is given then force at 17 4 3 far far farger can en feu yar aral fayd v m 9 1 4E0 2 3 8 0 9 16 0 4 45 9 32 o 33 fare f

A fluid is flowing through a horizontal pipe of varying cross section with v 1 ms at a point where the pressure is P Pascal At another point where pressure 1 P 2 Pascal its speed is V ms ms If the 3 density of the fluid is p kg m and the flow is streamline then V is equal to A B U D P 2p IP P tu 2P tu IP v

1 47 A ball is projected from ground with a speed of 20 ms at an angle of 45 with horizontal There is a wall of 25 m height at a distance of 10 m from the projection point The ball will hit the wall at a height of a 5 m b 7 5 m c 10 m d 12 5 m height and another Kk

A 72 B 72 Water freezes inside a pipe normally it expands by about 9 due to freezing What would be the pressure increase inside the pipe The bulk modulus of ice is 2 00 x 10 N m A 1 80 x 108 N m B 3 60 108 N m C 9 x 107 N m D 7 2 x 108 N m 27

4 20 V The potentiometer is best for measuring voltage as 1 It has a sensitive galvanometer 2 It has wire of high resistance 3 It measures potential difference in closed circuit ZAN It measures potential difference in open circuit Read Office Aak

An ideal gas has molar heat capacity at constant pressure Cp 5R 2 The gas is kept in a cylindrical vessel fitted with a piston which is free to move Mass of the frictionless piston is 9 kg Initial volume of the gas is 0 0027 m and cross section area of the piston is 0 09 m The initial temperature of the gas is 300 K Atmospheric pressure Po 1 05 x 105 N m An amount of 2 5 x 104J of heat energy is supplied to the gas then A B C D Initial pressure of the gas is 1 06 x 105 N m Final temperature of the gas is 1000 K Final pressure of the gas is 1 06 x 105 N m Work done by gas is 9 94 x 10 J

A bar magnet and a wooden bar identical in dimension and mas released from same height to fall under gravity passing through multiple rings of conducting material Time taken by bar magnet is T and by wooden bar is T2 Then which is possible out of given options O T1 T2 O T T2 O T1 T2 O None of these

69 Force on the short dipole due to the point charge kept on the equator of the dipole in the configuration shown in the figure is 1 Zero Oga d 2 2a Qqa Red Oga