Basic Physics Questions and Answers

The point of this question is to compare rest energy and kinetic energy at high speeds An alpha particle a helium nucleus is moving at a speed of 0 9990 times the speed of light Its mass is 6 40 x 10 27 kg Question What is its kinetic energy

Y O If u a bj and v pi qj O orientation of two vectors u and v in the XY plane Which of the following is correct O X a a and p are positive while b and q are negative b a p and b are positive while q is negative c a q and b are positive while p is negative d a b p and q are all positive X

Lower end of a uniform inextensible rope of length 4m and having mass 2kg is attached to a block which is at rest due to sufficient friction Tangent at lower end is horizontal F Upper end is pulled with hand by a force F tangentially so that whole system is in equilibrium Take tan 0 5 26 5 List l List II P Force applied by hand in N Q Friction acting on block in N R Angle made by F with horizontal in degree S Tension at half the height of hand in N OP 4 Q 3 R 5 S 2 2m OP 20 3 R 5 S 1 1 37 2 3 20 4 25 5 53 15

Two particles 1 and 2 start from origin and move along same straight line in same direction The acceleration versus time graph of both particles is shown in figure Choose correct statement s about the motion of 1 and 21 A During motion from O to T somewhere one particle will overtake the other B During motion from O to Taverage speed of both the particles is same C During motion from O to T average speed of both the particles are different D Displacement covered by the two particles from O to T are same

1 57 A point charge Q is located on the axis of a disc of radius R at a distance a from the plane of the disc If one fourth of the flux from the charge passes through the disc then find the relation between a R R Ans a

Consider the solid of revolution formed by revolving about the y axis the region in the first quadrant bounded the curve y 4 x and the coordinate axes where x and y are both measured in meters a Use the cylindrical shell method to find the volume of the solid

There is a narrow bridge somewhere on a road connecting two towns Two cars travel from one of the towns to the other with a constant speed U everywhere on the road except on the bridge where they travel with another constant speed U How the separations between the cars varies with time t is shown in the following graph 8 m 4 8 500 8 200 1 80 100 tls t 10 30 a What is the speed u of the cars on the road b What is the speed v of the cars on the bridge c What is length of the bridge

Q2 The 8 bit registers AR BR CR and DR initially have the following values AR 11010010 BR 11100011 CR 10111001 DR 10101011 Determine the 8 bit values in each register after the execution of the following sequence of microoperations AR AR BR CR CR DR BR CR 1 AR AR CR 5 marks

3 52 The space between two conducting concentric spheres of radii a and b a b is filled up with homogeneous poorly conducting medium The capacitance of such a system equals C Find the resistivity of the medium if the potential difference between the spheres when they are disconnected from an external voltage decreases n fold during the time interval At Ans Atx 4 ab C b a logen

in the part of a circuit shown in figure the potential difference Vo VH between points G and H will be 1A G2A 4023 3V ov 202 ww 10 5V 3A

ALLEN Two point charges 5 C and 2 C are kept at a 43 distance of Im in free space The distance between the two zero potential points on the line joining the charges is 1 m 2 m 3 m 4 20 21 m a fa de fair f i tr t ti an far ardi ton gu fava fargen a aft att t 1 m 2 m 50 22 4 20

3 P P P 4 P P P When a current flows through a conductor its 29 temperature 1 May increase or decrease 2 Remains same 3 Decreases 4 Increases 3 P P P 814 h 1 2 kafa tal 3 4 gal 4 P P P at se

This section contains 35 SINGLE CORRECT TYPF questions Each question has 4 Read More An electric field in a certain region is radially outwards from origin and has a magnitude equal to Ar 2 where ris distance from the origin The charge contained in a sphere of radius R centered around origin is 4 E AR7 2 4 E ARS 2 6T AR

1 73 A point charge q mass 100g experiences a force of 100N at a point at a distance 20cm from a long infinite uniformly charged wire If it is released find its speed when it is at a distance 40cm from wire Ans 20 In 2

An iron rod of susceptibility 599 is subjected to magnetising field of 1200 A m 1 The permeabili of the material of the rod is NEET 2020 Phase 1 Mo 4 x 10 7 Tm A 1 8 0 x 10 5 T m A 1 2 2 4 10 5 T m A 1 3 2 4 x 10 7 Tm A 1 4 2 4 x 104 I m 0 1

Two blocks each having mass M rest on frictionless surfaces as shown in the figure If the pulleys are light and frictionless and M on the incline is allowed to move down then the tension in the string will be 1 Mg sin 0 2 2 2 2 Mg sin 0 M o fixed 3 M Mg sine 2 4 2 Mg sin 0

A block of mass m is connected to a spring spring constant k Initially the block is at rest and the spring is in its natural length Now the system is released in gravitational field and a variable force F is applied on the upper end of the spring such that the downward acceleration of the block is given as a g at where t is time elapsed and a 100 m s3 find the velocity in m s of the point of application of the force at t 2 sec m 2kg k 100 N m F 000000 k

a Convert the 8 bit Sign and Magnitude binary number 1010 01012 to decimal b Convert the 8 bit Sign and Magnitude binary number 0011 10012 to decimal

that of sr with er one particle Then net omplete 9 Consider a square ABCD of side 1 m each as shown in figure Then OA AB BD will have a magnitude of 1 1 m 3 2 m A B 2 2 m 4 1 2 m

R Two balls of equal masses are thrown upward along the same vertical line at an interval of 2 seconds with the same initial velocity of 40 m s Then these collide at a height of Take g 10 m s A 120 m B 75 m C 200 m D 45 m

of suspension For such a rope general equation for z use A long rope is design as shown in the figure such away that v independent of z is distance from point cannot be constant Where is leniar density of rope what is the as mass per unit length of the rope at point z 0 a 4 8 z b Hoe 8 0 2 c 4 e 8 v z d M 4 0e 8 0 2 A string of length L consists of two distinct sections The left half has linear mass density 40 2 Z dz

5 97 Determine the reactions at A for the cantilever beam subjected to the distributed and concentrated loads Ans A 0 A 8 kN M 21 kN m MA y 3 m 4 kN m 2 kN 1 5 m 1 5 m I

Q No 26 A sphere of radius 10 cm is charged to a potential of 3000 V The outward pull per unit area of its surface is 1 3 4 4x10 3 N m 2 10 3 N m 1 10 3 N m Zero Correct Answer 1 Status unattempted

Three identical balls are placed on a smooth horizontal surface as shown in figure Each of them is smooth and has mass m Three balls are touching the horizontal surface and fourth is placed above them Assume that the mg find k balls on the horizontal surface just touch each other The tension in the thread connecting is k

A car is running on a road at a uniform speed of 60 km h The net resultant force on the car is A driving force in the direction of car s motion B resistance force opposite to the direction of car s motion C an inclined force D equal to zero

Assume that z 0 plane is the interface between two linear and homogeneous dielectrics see figure The relative permittivities are r 5 for z 0 and 4 for z 0 The electric field in the region z 0 is E 31 5j 4k kV m If there are no free charges on the interface the electric field in the region z 0 is given by 8 5 i i k kv m e 4 E 37 51 k kV m E 31 51 5k kV m E 37 5j 5k kV m

Three decal cylinders each of mass m are placed on a horizontal smooth surface as shown in figure Horizontal force F can vary between maximum and minimum value so that all three cylinders always move together List P Normal force between 1 3 when F is minimum Q Normal force between 2 3 when F is minimum R Normal force between 1 3 when F is maximum S Normal force between 1 2 when F is maximum List ll 1 2 3 4 2mg 3 3 3mg 2 2mg 3 mg 3 X

A non conducting sphere of radius a has a net 20 charge q uniformly distributed throughout its volume A hollow spherical conductor having inner and outer radii b and e and net charge q is concentric with the sphere see the figure Read the following statements i The electric field at a distance r from the centre of the sphere 1 qr 4x o a ii The electric field at distance r from the centre of the sphere for a r b 0 for r a iii The electric field at distance r from the centre of the sphere for b r c 0 iv The charge on the inner surface of the hollow sphere q v The charge on the outer surface of the hollow sphere q Which of the above statements are true 1 i ii and v 3 ii iii and iv husiast Leader Achiever All Phase H29072020 2 i iii and iv 4 ii iii and v a from alle s q gu fakta ya al forn at a fe t d t 3dz q i fan m t m i t for f farger 1 r a 1 qr 4x o a ii a r br 0 r iii b r cf au faga 27 0 iv 3 v 1 i ii 3 ii iii faga V iv 2 i iii 2 iv 4 ii iii v 1001CMD303119101 Pano 7 53

A solid A B having ZnS structure zinc blende is heated so that the ions along one of the body diagonal are lost and trivalent ion C enters here to maintain the electrical neutrality so that the new formula of lattice becomes A B C Report the value of y x z where x y and z are smallest natural numbers 90 00

A cylinder adiabatic contains He and O of equal volume separated by a massless freely movable piston as shown If the gas is adiabatically compressed by moving the upper piston so that volume of He becomes half If A is the cross sectional area of the cylinder the volume LA occupied by O is where n is The middle piston is also adiabatic in nature 221 He massless 0 Ay

4 2500 2 in parallel Figure shows three resistor configurations R R 28 and R connected to 3V battery If the power dissipated by the configuration R R and R is P P and P respectively then R 152 1 P P P 3 P P P R 152 008 043 152 R 4 2500 2 f3 e 2 P P P 4 P P P configurations R R R fara fa R R R P at at R tu da facu 1 P P P3 3 P P P R P P R 2 P P P 4 P P P

ALLEN Two spherical conductors A and B of radius a 30 and b b a are placed in air concentrically B is given charge Q coulomb and A is grounded The equivalent capacitance of these is 2 4 o a b 1 4 ab b a A B a b den any B QT I at sa 1 4 ab a 2 4 o a b

Two blocks B and C of mass 1kg and 3kg respectively rests on a bracket A of mass 1kg Constant forces F 20 N and F 8N are applied on block C and bracket A then initial acceleration of bracket A is All surfaces are smooth 1 4 m s 3 16 m s A B 2 2 m s 4 12 m s

Two particles are moving on a plane with constant but different velocities Separation between them as a function of time is as shown in figure All values in list II are in S I unit m List I P Magnitude of slope of graph at t 0 Q Slope of graph at t 8 sec R Magnitude of angular velocity of one particle with respect to other at t 8 sec S Slope of graph at very large time 12 List II 1 5 2 5 8 2 5 3 5 53 3 3 4 5 5 58 18 t s

The block diagram of a feedback control system is shown in Figure 2 R GR H Gp Figure 2 a Write the closed loop transfer function of the feedback system in terms of

The given circuit can 220 i yi 3 R 1 2 12 1 x R 1 R 0 2 Reff R R Ri RI RIS R R13 R P12 S R KA be redrawn as 4 1 3 2 14 N m 3 12 R I Re 3 1 2 1 2 1 72 12 1 20 11 12 12 2 1 201 RR v iReff i 220 Reff i 5x220 R 1 1 1 Pett RUND 12 iz 1 1 1 5 1 3 1100 1100 I 1 Amp

For measuring voltage of any eris faxeit i ukuu at ald 4147 f y alcul r at g u fawujui as aktual di Girdi quia OPTIONS MARK FOR REVIEW CLEAR SELECTION O A The potentiometer is cheap and easy to handle A HIG GIF B Calibration in the voltmeter is sometimes wrong ale ad The potentiometer draws no current during measurement THE BEURT HE Range of the voltmeter is not as wide as that of the potentiomotor

What is the largest mass of C in kg that can be suspended without moving blocks A and B The static coefficient of friction for all plane surface of contact is 0 3 Mass of block A is 50kg and block B is 70kg Neglect friction in the pulleys a 120 kg b 92 kg c 81 kg d None of the above A B

5 A closely wound solenoid of 2000 turns and area of cross section 1 5 x 10 4 m carries a current of 2 0 A It is suspended through its centre and perpendicular to its length allowing it to turn in a horizontal plane in a uniform magnetic field 5 x 10 2 tesla making an angle of 30 with the axis of the solenoid The torque on the solenoid will be AIPMT Mains 2010 1 3 10 N m 2 1 5 10 3 Nm 3 1 5 10 2 Nm 4 3 x 10 Nm

The x y z co ordinates of two points A and B are given respectively as 0 1 2 and 1 3 1 The unit vector along the displacement vector A to B is given by 2j 3k 14 2j 3k 14 i 2j 3k

marks Two blocks of masses 5 kg and 3kg are placed in contact over an inclined surface of angle 37 as shown is friction coefficient between 5kg block and the surface of the incline and similarly 2 is friction coefficient bet the 3kg block and the surface of the incline After the release of the blocks from rest on the inclined surface if 0 5 and H 0 3 then 5 kg block exerts 3N force on the 3 kg block if 0 5 and 2 0 3 then 5 kg block exerts 8 N force on the 3 kg block if 0 3 and 0 5 then 5 kg block exerts 1 N force on the 3kg block if p 0 3 and 0 5 then 5 kg block exerts no force on the 3kg block 5kg 3kg H H 37

A conducting rod of mass m is placed in contact with two long conducting rails placed parallel with a distance L between them The resistance of the rod and the rails is negligible Two ends of the rails are connected by a wire of resistance R and the whole setup lies on an insulating horizontal surface A uniform magnetic field of intensity B exists in a direction perpendicular and into the plane of the paper At t 0 the rod is given a velocity v perpendicular to its length as shown The rod moves on the rails without friction At subsequent time instants

A 23 Two particles A and B located as shown start moving simultaneously with constant velocities VA V 4 m s and VB 41 m s The shortest distance between them is x 2 m then value of x Y B 4 4

3 20 20 4 16 18 One mole of an ideal monoatomic gas at 36 temperature T expands slowly according to law P kV k is constant If final temperature is 2T heat supplied to gas is 1 2 RT 3 RT 2 3 2 RT 4 RT 2 3 20 20 P kV k is constant a 4 16 18 1 2 RT 3 RT 0 af sifa y 2 3 2 RT 4 RT 2 y

The figure shown a hexagonal swimming pool A person standing at point A on ground wants to reach point B see figure in least possible time The person can move with a speed V on ground and with a speed in pool Find the least possible time in which the person can go from A to B Given 2 OA OB 51

Now the devices maintaining temperatures of the pistons are removed and the pistons are covered with heat insulating materials After a sufficiently long time when a steady state is reached again what will the distance between the pistons become a 80 0 cm c 89 2 cm b 88 9 cm d 92 7 cm

Steam at 100 C is passed into 22g of water at 37 20 C The mass of water that will be present when the water acquires a temperature of 90 C Latent heat of steam is 540 cal g is 1 24 8 gm 2 24 gm 3 36 6 gm 4 30 gm 100 C 22 90 C 1 24 8 gm 2 24 gm 3 36 6 gm 4 30 gm 20 C you a 540 cal g

3 A beam of ultraviolet light with wavelength of 250 nm is incident on a metal whose work function is 2 8 eV Note that 1 5 V is applied to the metal with respect to the photoelectron detector Determine the largest kinetic energy of the photoelectrons collected by the detector

An elastic ball thrown with a speed vo from ground level collides with a vertical wall when it is moving at right angles to its initial direction of motion and subsequently strikes the ground after a time possible time of its motion for the given speed of projection Find angle of projection in degrees 2 3 of the maximu

order reaction For A g 3B g 2C g If initial pressure of A is and after time t from the start of reaction the total pressure is p then the rate constant of reaction is given by Po NCERT Pg 106 1 In 2 the first 40 2 In 4 In p 5p 4p 4p