Physics Questions

0 An AC voltage e eo sin 50t e cos 100mt is connected in series with a resistor and capacitor The steady state current through circuit is found to be 1 lo sin 50nt o lo cos 100nt 10 lo Then the ratio of a greater than 1 c less than 1 is b equal to 1 d None of these

D Consider a system of two particles having masses m and m If the particle of mass m is pushed towards m through a distance d by what distance should be particle of mass m be moved so as to keep the centre of mass of the system of particles at the original position 1 m d m m 3 d mid 2 m2 4 m2 d m

Which of the following graphs correctly shows the variation in kinetic energy KE of a metal sphere falling freely in a lake Assume sufficient depth of the lake to impart terminal velocity to the sphere d is depth 1 3 KEA 2 KEA 2 4 KE KEA d

34 A sinusoidal voltage of peak value 200 volt is connected to a diode and resistor R in the circuit shown so that half wave rectification occurs If the forward resistance of the diode is negligible compared to R then the rms voltage involt across R is approximately 8 200 Volt 200

Magnetic field through a coil is changed with respect to time then emf induced in it then select the incorrect regarding induced emf in coil 1 Coil may be made up with wood 2Coil may be connected with an open circuit 3 Coil must be of conducting nature Induced emf does not depends upon resistance of the coil ct

Example 10 11 Young s double slit experiment is carried out using microwaves of wavelength 3 cm Distance between the slits is d 5 cm and the distance between the plane of slits and the screen is D 100 cm i Find the number of maximas and ii Their positions on the screen

24 A hemisphere of volume v is kept in a liquid of density p as shown in figure Vertical thrust on the hemisphere due to liquid inside it is 1 vpg 3 vpg A 0 1 1 1 8 2 8 9 8 6 0 2 2 vpg 4 Zero

B 1 v vo 2 v v 3 v v 4 v v The armature coil of dynamo is rotating The generated induced emf varies and the number of magnetic lines of force also varies Which of the following condition is correct 1 lines of flux will be minimum but induced emf will be zero 2 lines of flux will be maximum but the induced emf will be zero 3 lines of flux will be maximum but induced em will be not be zero 4 the lines of flux will be maximum and the induced emf will be also maximum

41 A block of mass 10 kg is moving on a rough surface as shown in figure The frictional force acting on block is v 4 m s 1 20 N 3 40 N TTTTT 0 6 10 kgh 2 4 F 20 N 60 N 80 N

13 A steel rod is 4 cm in diameter at 30 C A brass ring has an interior diameter of 3 992 cm at 30 C In order that the ring just slides on to the steel rod the common temperature of the two rods should be a 11x10 6 1 C a 19x10 6 1 C 1 200 C 2 350 C 3 280 C 4 300 C

116 The position x of a particle varies with time t as 4 X 3 Then the particle is t 1 Slowing down 2 Always moving towards x axis 3 Speeding up LAY Moving with constant speed

A block slides along a track from one level to a higher level by moving through an intermediate valley as shown in figure The track is friction less until the block reaches the higher level Then there is friction force which stops the block at a distance d The block s initial speed v is 6 0 ms the height difference h is 1 1 m and the coefficient of kinetic friction is 0 60 The value of d is 0 60 0

Question 14 A simple screw jack used in actual practice is A non reversible machine A reversible machine An ideal machine not a lifting machine

A positive charge Q is fixed at a point in space There is another charge q which moves in a circular path of radius r around the given fixed charge Assume that the electrostatic force between them is the only force acting on them Calculate time period of revolution of charge

6 The numbers 2 745 and 2 735 on rounding off to 3 significant figures will give a 2 75 and 2 74 c 2 75 and 2 73 b 2 74 and 2 73 d 2 74 and 2 74

10 If instantaneous current in a circuit is given by 2 3 sin wt A then the effective value of resulting current in the circuit is 1 3 17 2 3 2 A A 2 V17 4 3 2 A 2 A

View in Englah In any experiment to measure ratio of radi of circular paths Two particles having charge 20 and g are projected with same speed if the masses of particles are mand 2m respectively if these particles are projected perpendicularly in uniform magnetic field 8 then ratio of radil of their cecular paths will be 712 W

A charged particle of mass m and charge q travels on a circular path of radius r in a uniform perpendicular magneti field B The time taken by the particle to complete half revolution is 2 m qB m qB q mB 2 q mB

30 Force acting on a particle moving along x axis is as shown in figure Find points of stable and unstable equilibrium A F B C E

The focal is in cm 2 92 combination 1 6 4 12 88 Image of an object at infinity is formed by 3 108 a convexlens of focal length 30 cm such that the size of the image is 12 cm If a concave lens of focal length 20 cm is placed in between the convexlens and the image at a distance 26 cm from the convexlens size of the new image is 1 2 5 cm 2 2 0 cm 4 1 05 cm 3 1 025 cm

1 A small block B is placed on another block A of mass 5 kg and length 20 cm Initially the block B is near the right end of block A figure 5 E3 A constant horizontal force of 10 N is applied to the block A All the surfaces are assumed frictionless Find the time elapsed before the block B separates from A 10 N A

refractive index of 2 3 has a It is surrounded by air A light ray is incident at the midpoint of one end of the rod as shown in the figure The incident angle for which the light ray grazes along the wall of the dis

3 y 1 5 x 5 A particle starts moving with constant acceleration with initial velocity i 5 m s After 4 second its velocity becomes 31 21 m s The magnitude of its displacement in 4 second is 1 5 m 3 15 mm Or 2 2 10 m B 4 20 m 2 E

Two sinusoidal currents are given by the equation 50 sin at i 25 sin cot The phase difference between them is degrees Select one O a 75 O b 45 c 30 d 15

A string is fixed at a and its free end is at x 0 A triangular shape wave pulse is moving along the string with speed v m s in the positive x axis direction Its position at t 0 is shown in the figure TRENING The shape of wave pulse at t a 2v will be X 0

An object is at rest Now a force applied to it which give it an acceleration of a 2t ms What will be object velocity at t 3 s 161 61 ms 1 187 6 ms 1 81 61 ms 1 min 91 8 ms 1

3 2 224 A car is moving on a circular track at a speed of 20 m s having radius 100 m If it starts decelerating uniformly at the rate of 3 m s2 the angle made by the resultant acceleration with the direction of its instantaneous velocity is 1 37 3 53 2 127 4 143 230

int of as a resultant reaction and Applied force frictional force O normal reaction frictional force applied force the weight of the bo normal reaction the weight of the Previous Save Nex To be reviewed la

A diatomic gas of moleculer weight 30 gm mole is filled in a container at 27 C It is moving at a velocity 100 m s If it is suddenly stopped the rise in temperature of gas is 1 60 R 6x104 2 4 600 R 6x10

find the electric field at the location of qa in the figure below given that qb qc qd 1 35 nC q 1 00 nC and the square is 16 0 cm on a side the x axis is directed to the right a what is the magnitude in N C b what is the angle counterclockwise from the x axis i am also attaching the figure below 9a 4 9b

The resolution limit of eye is one minute at a di of 10 km from the eye two objects are at x m apart f two objects just resolved by the eye then x is 1 4 m 2 3 m 3 2 m 4 1 m

4 When alternating current flows through a conductor the rate of flux change 1 Is higher in the inner part of the conductor 2 Is lower in the inner part of the conductor 3 Is uniform throughout the conductor 4 Depends on the resistivity of the conductor

1 4 3 2 3 4 A number of small drops of mercury adiabatically 1 increase 2 remain same spherical 3 16 9 4 64 27 coalesce to form a single drop The temperature of the drop 3 decrease 4 depend on size

A conducting rod of length L is rotating about a perpendicular axis passing through point O as shown in figure The potential difference between ends M and Nis Y 2x7 1 M BOL 27 BOL X X X X X X X X X X 2L 3 X X X X X X XX X X X X X X X X X X X X X x O X X 100 2 1 X 13 L XX X X X BOL 6 BWL XX N X R E al BEN 2 2ZXW YU B 24

A block is placed on horizontal surface as shown in 16 figure Which of the following statement is correct The normal force on the block is not equals the weight because of Newton s third law 2 The normal force on the block equals its weight because of Newton s first law 3 The normal force on the block is equals its weight because of Newton s second law 4 All of these

13 A large open tank has two holes on the side wall One is a square hole of side L at a depth y from the top and the other is a circular hole of radius R at a depth 4y from the top When the tank is completely filled with water the quantities of water flowing out per second from both the holes are the same Then R is equal to 1 2nL 3 L 2 4 L 2 L 2 A

11 Consider a compound slab consisting of two different material having equal area cross section and thermal conductivities K and 4K The equivalent thermal conductivity of the slab is 0 A A 1 K 2 1 5 K 3 2 K 4 2 5 K K 4K B B 0 0 0

9 A model rocket fired from the ground ascends with a constant upward acceleration A small bolt is dropped from the rocket 1 0 s after the firing and fuel of the rocket is finished 4 0 s after the bolt is dropped Air time of the bolt is 2 0 s Acceleration of free fall is 10 m s2 Which of the following statements is are correct a Acceleration of the rocket while ascending on its fuel is 8 0 m s b Fuel of the rocket was finished at a height 100 m above the ground c Maximum speed of the rocket during its upward flight is 40 m s d Total air time of the rocket is 15 s

10 A massless rod of length is suspended by two identical string AB and CD of equal length A block of mass 10 Kg is suspended from point P such that DP is equal to X It is also observed that the frequency of 1st harmonic in AB is equal to 3rd harmonic frequency in CD Then find X C 10 l A B 10 Kg D 9l 10 AP

You have two lenses A and B of focal lengths 10 cm and 10 cm respectively State the nature and power of each lens Which of the two lenses will form a virtual and magnified image of an object placed 8 cm from the lens Draw a ray diagram to justify your answer

If Amin is minimum wavelength produced in X ray tube and is the wavelength of k line As the operating tub woltage is increased A increases min 3 increases NUGA 2 A decreases 4 decreases photo electric cell and

A homogeneous electric field and a uniform magnetic field Bare pointing in the same direction A proton is projected with its velocity parallel to It will Question Type Single Correct Type 1 Go on moving in the same direction with increasing velocity 2 Go on moving in the same direction with constant velocity

20 The cylindrical tube of a spray pump has radius R One end of it has n fine holes each of radius r If the speed of liquid in the tube is v the speed of the ejection of the liquid through the holes is 1 2 3 v R nr VR n r VR nr

A moving charge produces 1 electric field only 2 magnetic filed only both of them 4 none of these Two infinitely long thin insulated straight wires lie in the x y plane along the x and y axis respectively Each wire carries a current I respectively in the positive x direction and positive y direction The magnetic field will be zero at all points on the straight line UV x 2 y x 3 y x 1 4 y x 1 Jong wires Garry currents i and i with i i When the current are in the same direction the magnetic di in reversed the field becomes 30 T The ratio

13 A cylindrical wire of radius R is carrying current i uniformly distributed over its cross section If a circular loop of radius r is taken as amperian loop then the variation value of B de over this loop with radius r of loop will be best represented by 1 f5 di fo di R 2 B de 4 B de R 1

A 2 00 m long rope having a mass of 80 g is fixed at one end and is tied to a light string at the other end Th tension in the string is 256 N a Find the frequencies of the fundamental and the first two overtones b Find the wavelength in the fundamental and the first two overtones

Water is moving with a speed of 5 18 ms through a pipe with a cross sectional area of 4 20 cm The water wat gradually descends 9 66 m as the pipe increase in area to 7 60 cm The speed of flow at the lower level is 3 3 82 ms 4 2 86 ms 2 5 7 ms 1 3 0 ms l

5 3R 2 2 2R 1 Variation of pressure P with volume monoatomic gas is shown in figure The molar specific heat of the gas in the process will be 3 5R 2 4 3R P V

17 a An electron is shot directly toward the centre of a large metal plate that has surface charge density 2 0 x 10 6 Cm 2 The initial kinetic energy of the electron is 1 60 x 10 7 J The electron stops just when it reaches the plate due to electrostatic repulsion from the plate Calculate the distance of the starting point of the electron from the plate 3 b A 5 0 cm slab of ice is formed on an outdoor tank of water The air is at 10 C Find the rate of ice formation in centimeters per hour The ice has thermal conductivity 0 0040 cal s cm C and density 0 92g cm Assume there is no energy transfer through the walls or bottom 3

1 2 Two rods of different materials having coefficients of thermal expansion a and a2 and Young s moduli Y and Y respectively are fixed between two rigid massive walls The rods are heated such that they undergo the same increase in temperature There is no bending of the rods and junction does not shift If a and a are in the ratio 2 3 the thermal stress developed in the two rods are equal provided Y Y is equal to 2 1 2 3 3 3 2 2 1 1 4 4 9