Basic Physics Questions and Answers

2 If the angle of incidence is half of the angle refraction in a medium of refractive index u relative to first medium then the angle of incidence is NCERT Pg 317 1 cos 3 sin 1 2 2 1 2 1 2 cos 4 sin

A bike is travelling on a straight road with uniform acceleration During the first 5 seconds the displacement is 25m and in the next 5 seconds the displacement is 100m Find the acceleration of the bike in m

A narrow paraxial beam of light is converging towards a point I on a screen A plane plate of glass of thickness t and a refractive index is introduced in the path of the beam The convergence point is shifted by 1 t 1 1 u away 2 t 1 1 u away 3 t 1 1 nearer 4 t 1 1 nearer

positions x of particle with respect to time t along 24 X 37 T 3 fefdx 9t t 4 12 N X axis is given by x 9t t where x is in metre and t in second What will be the position of this particle when it achieves maximum speed along the X direction 1 32 m 2 54 m 3 81 m 4 24 m 2 3 18 6 18 3 Rixentant ferfa X 1 32 m 2 54 m 3 81 m 4 24 m 9 x 9 27 81 27 27 51

T If x a cos 0 0 sin 0 and y a sin 0 0 cos 0 where a is a constant find dx 3 The fuel consumption rate Litres of fuel consumed per second of a large ship is given by 3y where v is its speed in m s For a particular journey from city A to city B the captain wishes to consume as less fuel as possible Find the speed with which the ship must travel in m s 96 at x

Young Laplace law states that the inside a soap bubble of radius R is given by AP 40 R a tension of the soap The E tv s number Eo is a dimensionless number that is used to describe the shape of bubbles rising through a surrounding fluid It is a combination of g the acceleration due to gravity p the density of the surrounding fluid o and a characteristic length scale L which could be the radius of the bubble A possible expression for E is pg GL 3 where o is the coefficient of surface c Pg 2 PgL b d pL og gL

Two particles P and Q start from origin and execute simple harmonic motion along X axis with same amplitude but with periods 3 seconds and 6 seconds respectively The ratio of the velocities P and Q when they meet is 2001E 1 1 2 2 2 1 3 2 3 4 3 4

A particles of mass m 5 units is moving wit a uniform speed v 3 2 in the XOY plane alo the line Y X 4 The magnitude of the angu momentum of the particle about the origin is 1 zero 2 60 unit 3 7 5 unit 4 40 2 unit

A thin glass ro r A charge q is uniformly distributed along the upper half and a charge q is uniformly distributed along the lower half as shown in the figure The magnitude and direction of the electric field E produced at P the centre of the circle will be q 1 0 downward dius 2 2 2 perpendicular to the line OP and directed q E 3 Er 2019 20 downward perpendicular to the line OP and directed

3 36 m s 4 48 m s A paticle is executing S H M of amplitude a and time period 4s Then the time taken by it to move from the extreme position to half the amplitude is 1 1s 2 1 S 3 2 S 4 4 S

JEE ADV PHYSICS VOL V mperature of patch of skin of a healthy rson is 37 C Due to viral fever mperature increases by 5 4 Then rcentage change in rate of heat radiation om patch of skin is nearly 2 6 2 1 4 3 3 2 4 4 1 metallic spheres S and S are made JEE AC NUM 18 The of con rat

2 An astronaut jumps from an aeroplane After he had fallen 40 m then his parachute opens Now he falls with a retardation of 2 0 m s and reaches the earth with a velocity of 3 0 m s What was the height of the aeroplane For how long astronaut remained in air g 9 8 m s Ans 234 m 15 4 s

Figure shows two identical current i and an amperian loops encircling them The value of B dl is fea 469 GR R GRI fort B dl Oi A Hoi B 20 DO C Zero D i 2 i ufafan qut

88 A rod of cross sectional area 1000 mm is subjected to the following loading Ratio of the magnitudes of the maximum tensile stress to that of the maximum compressive stress developed in the rod is 300 N a 1 2 100 mm b 1 1 600 N 100 mm c 2 1 100 N 600 mm 200 N d None of the above C OON is applied to it

se by 2 times sel with faces horizontal vertical contains an ideal gas at NTP The vessel is being carried by a rocket which is moving at a speed of 500 m s in vertical direction The pressure of the gas inside the vessel as observed by us on the ground a remains the same because 500 m s is very much smaller than v of the gas rms b remains the same because motion of the vessel as a whole does not affect the relative motion of the gas molecules and the walls c will increase by a factor equal to 500 where v was the original mean square velocity of the gas rms d will be different on the top wall and bottom wall of the vessel

A cylinder of mass 5 kg and radius 30 cm is free to rotate about its axis it receives an angular impulse of 3 kg m s initially followed by a similar impulse after every 4 s What is the angular speed of the cylinder after 30 s of the initial impulse The cylinder was at rest initially

A thick walled hollow sphere has outer radius R It rolls down an inclined plane without slipping and its speed at the bottom is v If the inclined plane is frictionless and the sphere slides down without rolling its speed at the bottom is 5v 4 What is the radius of gyration of the sphere

5 The electric field associated with an electromagnetic waveinvacuumisgiven by E 40 cos kz 6x 10 t i where E and t are in volt per meter meter and second respectively The value of wave vector kis a 2m b 0 5 m c 6m d 3 m 23 P P a b

2 moles of a monoatomic gas is mixed with 4 moles of diatomic ideal gas The molar specific heat capacity of the mixture at constant volume will be 13R 13 R 14R 2R

5 A satellite is revolving round the Earth in an orbit of radius r with time period T If the satellite is revolving round the earth in an orbit of radius r Ar Ar r with time period T AT AT T AT then is 1 3 T 3 Ar 2 F Ar L 2 Ar 3 r 2 Ar r LY 4

All the particles of a rigid rotating body move in a circular path when the axis of rotation 1 passes through any point in the body 2 is situated outside the body 3 situated any where 4 passes through the centre of mass

18 T C x10 sec A Two fixed identical metallic spheres A and B of radius R 50 cm each are placed on a non conducting plane at a very large distance from each other and they are connected by a coil of inductance L 9mH as shown in figure One of the spheres say A is imparted an initial charge and the other is kept uncharged The switch S is closed at t 0 After what minimum time t does the charge on the first sphere decrease to half of its initial value A x 10 6 sec T B x10 sec 4 D 2 10 sec B

3 The de Broglie wavelength of an electron having 80 eV of energy is nearly leV 1 6x10 19 M of electron 9 1x10 3 kg Planck s constant 6 6 10 34 Js a 140 c 14 b 0 14 d 1 4 A

In the given circuit initially capacitor has some charge the switch is closed at t 0 Column 1 Variables A Charge v s time B Current v s time C Charge v s current Pq S r D Energy stored in capacitor v s time R p e r s Column 2 Possible graphs

A particle moves in a straight line with constant deceleration The particle travels 360 metres in 12 seconds After 12 seconds the velocity of the particle is 9ms Which formula would you use to find the initial velocity Ov u at s ut at S vt at v u 2as S t

An infinitely long wire with radius R 10 mm carries a current along the z direction with current density J r Jo A m with Jo 2 284 A m where r is the distance from the axis of the wire z axis Total current I J r 2 y R a Calculate the total current Tip Integrate the current density over the circular cross section of the wire b Calculate the magnetic flux density B r outside the wire 4

Consider the following PV diagram for a monoatomic gas The ratio of work done by the gas to the change in internal energy of the gas will be 2P P 1 3 3 1 Zero V 2V

A square wire loop having side a mass m and resistance R is moving along positive x axis with speed to enters into uniform steady magnetic field BB k att 0 sec as shown in the figure the magnitude of vo is sufficient so that the loop comes out from region of magnetic field with v Neglect any type of energy loss other than heat loss in resistance of wire of square 2 3B a given vo mR A the plot of speed of square versus

D A bicycle is resting on its stand in the east west direction and rear wheel is rotating at 100 revo lution per minute Length of each spoke is 30 cm and vertical component of earth s magnetism is 1 5x10 5 tesla If the emf induced in the spokes is 3x10 V the angle of dip will be 3 tan 3 1 tan 2 tan 3 4 tan 3 1

by ve propagating along x direction can have the following pairs of E and b EB d both a and b a E B c E B 20 A charged particle oscillates about equilibrium position with Fectrom 7 Whic mone space a

Graph between square of frequency fundamental and tension in wire is Straight line Parabola hr n Ellipse

c The wavelength of the wave changes only d None of these 26 An electromagnetic wave propagating along north has its electric field vector upwards Its magnetic field vector point towards a north c west b east d downwards 392 a 8 c 4 33 An ele x axis E 6 vector i

A Carnot refrigerator has coefficient of performance 8 If the surrounding temperature is 25 C the minimum temperature it can cool a body inside is 6 C 8 C 8 C

Ice at 14 0 degrees C and steam at 140 degrees are brought together at atmospheric pressure in a perfectly insulated container After thermal equilibrium is reached the liquid phase at 48 0 degree

Q 8 Q 9 A 10 10 10 B 10 10 20 C 10 20 20 D 10 20 40 The resultant of two forces acting at an angle of 150 is 10 kg wt and is perpendicular to one of the two forces The smaller force is A 10 3 kg wt B 20 3 kg wt C 20 kg wt D 20 3 kg wt The resultant of the two forces one double the other in magnitude is perpendicular to the samlar

Q37 If the capacitance of a equal to O A e T hc 8 e h CT 0 c e c a capacitor hr D he e measured in terms of a unit u made by combining the electronic charge e Bohr radius r Planck s constant h and speed of light c 238 127031 127031 Proctor Dear Candidate We request you to display your original Photo ID proof Your valid id proof shall be hardcopy of the admit card along with Passport Aadhar card PAN

93 From a tension test the yield strength of steel is found to be 200 N mm Using a factor of safety of 2 0 and applying maximum principal stress theory of failure the permissible stress in the steel shaft subjected to torque will be a 50 N mm b 57 7 N mm Ap c 86 6 N mm d 100 N mm

23 A balloon of volume V contains a gas of mass m at a pressure P and temperature 15 C Gas is pumped into the balloon so that its volume is doubled and the pressure is trebled If the temperature increases 6 C in the process find the ratio of the increase in mass to the original mass 1 34 5 2 239 49 3 199 21 4 3 4

4 An L 70 m long thin tape wound on a spool of radius ro 10 mm makes a tape roll of outer radius R 25 mm A motor used to wind the tape rotates the spool at a constant angular velocity and takes T 165 s t complete the winding Calculate length of the tape which has been woun in t 110 s from the beginning of the winding 2 Ans Aus 4 R 36 60 ro ro T R 8 2

97 Maximum deflection in a simply supported beam due to a central load P at the middle is PL PL 48EI 32 EI PL 64 EI 00 a b c PL 96Elom d

19 A rigid coupling is used to connect a 45 kW 1440 rpm electric motor to a centrifugal pump The starting torque of the motor is 225 of the rated torque There are 8 bolts and their pitch circle diameter is 150 mm The bolts are made of steel 45C8 Syt 380 N mm and the factor of safety is 2 5 Determine the diameter of the bolts uib Assume Sy 0 577S T Assume that the bolts are finger tight in

A copper penny slides on a horizontal frictionless table There is a square region of constant uniform magnetic field perpendicular to the table as shown Which graph shows the speed v of the penny as a function of time t Loop view t 100

96 For a simply supported beam carrying u d of o per unit length L over the whole span length the maximum slope and deflection are respectively CL4 48EI a c 3 L 16EI 3 L 8FI and and L4 6FI b d d GL 6EI L 3 2461 and and L4 SEI 3 5wL 384FL

Two ships I and 2 move with constant velocities 3 m s and 4 m s along two mutually perpendicular straight tracks toward the intersection point O At the moment t 0 the ships were located at the distances 120 m and 200 m from the point O How soon will the distance between the ships become the shortest and what is it equal to

OLV t The quantity X Eo is the permittivity of free space L is length V is the potential difference and t is time The dimensions of X are the same as that of 1 Resistance 2 Charge 3 Voltage 4 Current

c When a voltage measuring device is connected to ac mains the meter shows the steady input voltage of 220 V This means a input voltage cannot be ac voltage but a de voltage b maximum input voltage is 220 V c the meter reads not Vbut V and is calibrated to read V d the pointer of the meter is stuck by some mechanical defect 6

7 Figure shows plot of force magnitude vs time during the collision of a 50 g ball with wall The initial velocity of the ball is 30 m s perpendicular to the wall the ball rebounds directly back with same speed perpendicular to the wall The maximum magnitude of the force on the ball from the wall during the collision is F N F max 1 1000 N 3 1500 N 2 2 von 4 6 LAY 6 t ms 750 N 2000N 8

The wave produced in the wire of a sonometer are 1 Transverse progressive and polarized 3 Transverse stationary and polarized 2 Longitudinal 4 Transverse stationary and un polarised

236 Two small spheres are charged to a total charge of 5x10 5 C If force of repulsion between two spheres is 1N when they are placed 2 m apart then what is the charge distribution on both the spheres O A 2 8x10 5C and 3 2 x10 5C O B 3 8x104C and 1 2x104C O c 5x10 5C and 3x10 5C O D 1 2x105 C and 3 8 x10 5C Proctor Dear Candidate We request

The minimum value of y 5x2 2x 1 is If y x x then find at x 0 dy dx R 1 x sin x dx 0 Evaluate If f x x 6x 8 2 x 4 then find the value of x for which f x becomes zero 4 16 Evaluate 16 cos 0 sin 0d0