Physics Questions

The acceleration due to gravity at the latitude 60 on the earth becomes zero if the angular velocity of rotation of earth equal to 2g R g 3R 5g R LOR

long solenoid has n 420 turns per meter and carries a current given by I 35 0 1e 1 60t where I is in amperes and t is in seconds Inside the solenoid and coaxial with it i at has a radius of R 6 00 cm and consists of a total of N 250 turns of fine wire see figure below What emf is induced in the coil by the changing current Use the following ecessary t Assume is in mV and t is in seconds n turns m R

14 In the circuit all bulbs consume same power resistance of bulb 1 is 36 2 then resistance of bu 3 and 4 are BA 1 42 122 3 92 49 B 002 B 00 4 B m 00 2 422 92 4 99 90 Topic Cells i Choose 1 Av Com diam the

72 Two soap bubbles of the same soap solution have radii 3 cm and 1 5 cm If the excess pressure inside the bigger bubble is 40 dyn cm what is the excess pressure inside the smaller bubble 1 mark

Two stars of masses 3 x 1031 kg each and at distance 2 x 10 1 m rotate in a plane about their common centre of mass O A meteorite passes through O moving perpendicular to the star s rotation plane In order to escape from the gravitational field of this double star the minimum speed that meteorite should have at O is Take Gravitational constant G 6 67 x 10 11 Nm kg 2 B 2 4 x 10 m s 1 4 x 105 m s 3 8 x 104 m s 2 8 105 m s

iii the amplitude is doubled iv the gravity at a place is decreased Solve the following numericals 1 A man riding a scooter travels a distance of 50 metres in 20 seconds What is the speed of troualled a distance of 120 km in 3 hours whereas another train B travelled TI Mi

6270 From NCERI A charge of 10 e su is placed at a distance of 2 cm from a charge of 40 e s u and 4 cm from another charge of 20 esu The potential energy of the charge 10 e s u is in ergs 1 87 5 2 1125 3 150 4 250

2 A block of mass M is hanging over a smooth and light pulley through a light string The other end of the string is pulled by a constant force F The kinetic energy of the block increases by 20 J in 1s 1 the tension in the string is Mg 2 the tension in the string is F 3 the work done by the tension on the block is 20 J in the above 1 s 4 the work done by the force of gravity is 20 J in the above 1s Fin distance x If the stopping force is 4F

The displacement of a charge Q in the electric field E e i ez ezk is r ai bj The work done is 1 Q ae be 2 Q ae be 3 Q e b e2 4 Q e a b

53 2 2 2 1 1 For the path PQR in a conservative force field fig the amount of work done in carrying a body from P to Q from Q to R are 5 J 2 J respectively The work done in carrying the body from P to R will be 1 7 J R 2 3J 3 21 J 4 zero moving in a potential region given by U K x y z The force acting on the particle is given by

x Figure shows a particle sliding on a frictionless track which terminates in a straight horizontal section If the particle farts slipping from the point A how far away from the track will the particle hit the ground Paper moren 1 0m 1 At a horizontal distance of 1 m from the end of the track 2 At a horizontal distance of 2 m from the end of the track 3 At a horizontal distance of 3 m from the end of the track 4 Insufficient information To 5m

What is the magnetic flux through the loop in the figure B 3 20 T a 1 80 cm b 6 60 cm r1 3 80 cm and r2 4 00 cm Magnetic field B What is the magnetic flux through the loop in the figure B 3 20 T a 1 80 cm b 6 60 cm 3 80 cm and r 4 00 cm O 1 72x10 5 Tm 1 91x10 5 Tm O 0 00380 Tm 0 00380 Tm

A body of mass m kg initially at rest attains a velocity of v m sec in time t under the action of a constant force F T power supplied to the mass is 1 mv t 2 mv t 3 Fv 4 Fv 2

To improve resolving power of a telescope a increase aperture of lens b increase wavelength of light c decrease aperture of lens d decrease wavelength of light Question Type Single Correct Type 1 a b 2 a d

A particle executing S H M its potential energy V S displacement graph is given by PE 24 J M 2 The value of restoring force constant is Question Type Single Correct Type 1 12 N m 2 24 N m 3 6 N m A m 48 N m 2 m

The escape velocity of a body from earth s surface is ve The escape velocity of the same body from a height equal to 7R from earth s surface will be Question Type Single Correct Type 1 2 Ve 2 Ve 2

The emitter base junction of a transistor is biased Question Type Single Correct Type 1 Reverse forward Reverse reverse biased while the collector base junction is

A coil of inductance 300 mH and resistance 20 is connected to a source of voltage 2V What is the value of time at which current will be 0 5Amp Question Type Single Correct Type 1 0 3s 2 0 15S 3 0 1s

In a metre bridge experiment null point is obtained at 20 cm from one end of the wire when resistance X is balanced against another resistance Y If X Y then where will be the new position of the null point from the same end if one decides to balance a resistance of 4X against Y Question Type Single Correct Type 1 50 cm 2 80 cm 3 40 cm 4 70 cm

Let M be the mass and L be the length of a thin uniform rod In first case axis of rotation is assing through centre and perpendicular to the length of the rod In second case axis of rotation passing through one end and perpendicular to the length of the rod The ratio of radius of yration in first case to second case is A 1 B 2 1 C D 81

Two moles of helium gas are taken along the path ABCD as shown in diagram The work done by the gas is Question Type Single Correct Type 1 2000R 1 2 In 3 2 500R 3 In 4 3 500R 2 In 20000 16 9 16 D A 20 15 10 5 A 250 500 750 1000 T K

A magnetic needle laying parallel to a magnetic field requires W unit of work to turn it through 60 The torque needed to maintain the needle in this position will be Question Type Single Correct Type 1 3W 2 W 3 3 2 W

In Y D S E distance between slits and screen is 1 5 m when light of wavelength 500 nm is used then 2nd bright fringe is obtained on a screen at a distance of 10 mm from central bright fringe what will be the shift in position of 2nd bright fringe if light of wavelength 550 nm is used Question Type Single Correct Type 1 1 mm 2 11 mm 3 2 mm 4 10 mm

An electron moves on a straight line path XY as shown The abcd is a coil adjacent to the path of electron What will be the direction of current if any induced in the coil Question Type Single Correct Type 1 No current induced 2 abcd 3 adcb a electron d Y

60 3 Three identical balls A B and C each of mass m 3 kg are connected by strings AB and BC as The whole system is placed on a smooth horizontal surface Now the ball B is given an initial velocity v perpendicular to the strings and along the horizontal surface Find the tension in Newton in the string just be the balls A and C collide BMR Doubt 1m Im

The temperature gradient in a rod of 0 5 m length is 80 C m If the temperature of hotter end of the rod is 30 C then the temperature of the cooler end is Question Type Single Correct Type 1 40 C 2 10 C 3 10 C

At a given instant there are 25 undecayed radioactive nuclei in a sample After 10 sec the number of undecayed nuclei reduces to 6 25 the mean life of the nuclei is Question Type Single Correct Type 1 14 43 sec 2 7 21 sec 3 5 sec

produced will be heat 1 350 cal The amount of work done 1 5 000 J 2 150 cal 3 60 cal 4 6 cal in pumping water out of a cubical vessel of height 1 m is nearly Take g 10 m s 2 10 000 J 3 5 J 4 10 J S fm 10 m

A steam boat goes across a lake and comes back on a quiet day when the water is still and ii on a rough day when there is a uniform current so as to help the journey onward and to impede the journey back If the speed of the launch on both days was same the time required for the complete journey on the rough day as compared to that on the quiet day will be 1 less 2 same 3 more 4 cannot be predicted

1 2as If a spring extends by x on loading then the energy stored by the spring is T is the tension in the spring and K is force constant 2x T 1 2 2 T 2K The elastic potential energy of a spring 2 2K T 2x only when it is stretched

A block of mass m rests on a platform The platform is given up and down SHM with an amplitude d What can be the maximum frequency so that the block never leaves the platform Question Type Single Correct Type 1 g d 2 3 1 2 gid 1 2 9 d

Three blocks are suspended by vertical strings from two lightweight rods of length 1 0 59 m as shown in figure If m 7 9 kg ma 3 kg and the distance x 0 23 m Neglect the masses of the rods and strings What is the mass of the block m m

A current i is uniformly distributed over the cross section of a long hollow cylindrical wire of inner radius R and outer radius R Magnetic field B varies with distance r from the axis of the cylinder as Question Type Single Correct Type 1 2 3 4 B4 B4 B4 B4 r

When a body of mass m is suspended from a spiral spring of natural length L the spring gets stretched through a distance h The potential energy of the stretched spring is mgh2 mgh 1 2 mgh pressib 4 mg L h w as ds Jw dr 55

If 76 eV energy is required to move a proton between two points then the potential difference between them will be 38 V 152 V 76 V

The kinetic energy K of a particle moving in a straight line depends upon the distance s as K as The force acting on the particle is Look 1 2as 2 2mas 3 2a 4 as on loading then the energy stored by the spring is T is the tension in the spring and K is forc

When a man walks on a horizontal surface with constant velocity work done by G 1 friction is zero 2 contact force is non zero 3 gravity is non zero 4 None of these dieplacement of the body in metre is a function of time as follows

P V and P V are initial and final pressures and volumes of a gas in a thermodynamic process respectively If PV constant then the amount of work done is Question Type Single Correct Type 1 minimum for n y 2 minimum for n 1 3 minimum for n 0 4 1 minimum for n x

If a force F is applied Fv 2 F v 3 F v 4 Fv A train weighing 10 N is running on a level track with uniform speed of 36 km h the frictional force is 0 5 kg f per quintal What is the power of the engine g 10 m sec 1 0 5 kw 2 5 kw 3 50 kw 4 500 kw A man is riding on a cycle with velocity 7 2 km hr up a hill having a slope 1 in 20 The total mass of the man and cycle

Two springs of spring constants 1500 N m and 3000 N m respectively are stretched with the same force They will have potential energy in the ratio 1 4 1 2 1 4 43 2 1 4 1 2 menended from a spiral spring of natural length L the spring gets stretched through a

1 0 5 kw 2 5 kw 3 50 kw A man is riding on a cycle with velocity 7 2 km hr up a hill having a slope 1 in 20 The total mass of the man and cycle is 100 kg The power of the man is 98 W 2 49 W 3 196 W 4 147 W A body of mass m kg initially at rest attains a velocity of v m sec in time t under the action of a constant force F The

W A bullet of mass 0 04 kg moving with speed of 90 m s enters into heavy wooden block and is stopped after a distance of 60 cm The average resistive force exerted by the block on bullet is 160 N

In an isothermal reversible expansion if the volume of 96 gm of oxygen at 27 C is increased from 70 litres to 140 litres then the work done by the gas will be Question Type Single Correct Type 1 300 R log10 2 2 81 R loge 2 3 900 R log10 2 23 x 900 R log 2

A water fountain on the ground sprinkles water all around it If the speed of water coming out of the fountain is V the total area around the fountain that gets wet is Question Type Single Correct Type 1 2 V 77 2 g 4 V g 3 T k V 75 g V4 a2

A non uniform rod of length has linear mass density Aoz where Ao is a positive constant The rod is pivoted at point P and is free to rotate in the vertical plane without friction as shown in the figure below The rod is released at rest is the gravitational acceleration Find the speed of the bottom tip of the rod when it is in the vertical position O O O None N For 2gl 2gf 21 too M

A spherical ball is dropped in a long column of viscous liquid The acceleration of ball as a function of time may be best represented by the graph Question Type Single Correct Type 1 2 3 V a F

1 s 2 s 3 s A force acts on a 3 gm particle in such a way that the position of the particle as a function of time is given by x 3t 4t t where x is meters and t is in seconds The work done during the first 4 second is 1 384 mJ 4 541 mJ od to 2 168 mJ 3 528 mJ lowor vertically a block of mass M at a distance x at a constant downward acceleration g 2 The work

4 A box of mass 20 kg is connected to mass of 2 kg hanging through a light string and an ideal pulley as shown in figure Coefficient of kinetic friction between trolley and surface is 0 05 What is acceleration of the box g 10 m s 20 kg Box TITT RATTAKENTEENTHETT

4 A particle moving along a straight line has velocity v m s when it covers a distance x along positive x axis The relation between two quantities is y 49 x When the velocity of particle is 1 m s its acceleration will be

3 A mass of 6 kg is suspended by a rope of length 2 m as shown in figure A force of 80 N is applied at mid point Pas shown What angle the rope makes with vertical under equilibrium Take g 10 m s 0 1m 80 N