Physics Questions

An alternating voltage is connected in series with a resistance R and an inductance L If the poten tial drop across the resistance is 200 V and across the inductance is 150 V then applied voltage is 1 350 V 2 250 V 3 500 V 4 300 V

D C moves to left A to night A vessel containing a liquid is heated with its contents The pressure at the bottom of vessel due to the liquid should no evaporation take place A increase C increases if Ysq 3 vessel B decrease D decreases if Yg 3 vessel academy com 61

A rough wedge of slant length 5 m is kept as shown in the figure Find the height h if the block of weight 10N just starts to slip in the given figure The coefficient of friction between the block 1 the wedge is

Two equal and opposite forces each of magnit F is applied along a rod of transverse sectional area A The normal stress to a section PQ inclined to transverse section is ar 0 F 1 3 F sine A sin 20 2 4 P F A A Q AS cose Ecos 0 F

um current from a combination of cells now should the cells be grouped a Series b Parallel c Mixed d Depends upon the relative values of external and internal resistance

A blind person after walking 10 steps in one direction each of length 80 cm turns randomly to the left or to right by 90 After walking a total of 40 steps the maximum displacement of the person from its starting point can be a zero c 16 2m b 8 2m d 32 m

the Example 6 5 A block of mass m is placed on the inclined surface of a wedge as shown in Fig 6 249 Calculate t acceleration of the wedge and the block when the block is released Assume all surfaces are frictionless m 340 0

39 In the circuit shown the value of I in ampere is a 1 b 0 60 c 0 4 d 1 5 452 www 4V 492 www 492 492 1 692

50 In the above problem between the two fragments when their position vectors are perpendicular to each other is 1 40 m 2 20m 3 10m 4 5m 51 At a certain height a shell at rest explodes into two equal fragments One of the fragments receives a horizontal velocity u The time interval after which the velocity vectors will be inclined at 120 to each other is 3u 2u u u

5 A projectile is fired at some angle 0 with speed such that it crosses two walls of equal height symmetrically as shown The angle of projection with horizontal is Y vertically 1 53 3 45 t 2s 0 120 m t 6s X 2 37 4 60

If a semiconductor has an intrinsic carrier concentration of 141x 10 6 m when doped with 1021 m phosphorous atoms then the concentration 3 of holes m at room temperature will be a 2 x 10 1 b 2 x 10 1 2009 c 1 41x 10 0 d 141x10 6

is placed on a horizontal platform which undergoes vertical simple harmonic motion of angular frequency The amplitude of oscillation is gradually increased The coin will leave contact with the platform for the first time a at the mean position of the platform b for an amplitude of c for an amplitude of 00 3 0 3 2006

A solid sphere falls into a viscous AP liquid from a large height Which of the graphs shown best represents the variation of velocity of sphere in liquid with time a P c R b Q d S P

A force F x i x 2 N acts on a particle which moves in the XY plane a 1m Find the work done by F as it moves the particle from A to C fig along each of the paths ABC ADC and AC YK a C D A a B X

points A and Cof a circular conductor ABCD with O as centre and angle AOC 60 If B and B are the magnitude of the magnetic fields at O due to the B B currents in ABC and ADC respectively then ratio is 1 1 3 5 AF IAA B O 60 D C 1272 4 6 16 P X

In a cubical box of volume V there are N molecules of a gas moving randomly If m is mass of each molecule and v2 is the mean square of x component of the velocity of molecules then the pressure of the gas is mNv SICS 1 P 3 V 3 P mNv 2 4 P mNv V P mNv

A horizontal metallic rod of mass m and length is supported by two vertical identical springs of spring constant K each and natural length fo A current i is flowing in the rod in the direction shown If the rod is in equilibrium then the length of each spring in this state is A fo i B mg K B lo i B mg 2K C lo mg i B 2K D lo mg i B K OB

In a Quincke s tube there are two positions where sound becomes minimum the sliding distance between the is 16 6 cm Find the freq of sound source Sound velocity in air 332 m sec A tuning fork having frequency 300 Hz produce four beats ner ser with x If we file arm of unknown and ag

6 The mass of a copper piece is 44 g A measuring cylinder contains water to a level of 12 mL The water level rises to 17 mL mark when the copper piece is dipped in the measuring cylinder Find i the volume of copper piece and ii the density of copper when and 5 the r Solution bottle M Mas Mas

171 The solids which have the negative temperature coefficient of resistance are metals insulators only semiconductors only insulators and semiconductors W 1 2 butt tember Sime 2

Three particles start from origin at the same time with a velocity 2ms 1 along positive x axis the second with a velocity 6ms 1 along negative y axis Find the velocity of the third particle along x y line so that the three particles may always lie in a straight line a 3 3 b 3 2 d 2 2 c 3 2

A cathode emits 1 8 x 10 7 electrons s and all the electrons reach the anode when it is given a positive potential of 400 V Given e 1 6 x 10 C the maximum anode current is 1 2 88 mA 3 7 2 mA 2 28 8 mA 4 6 4 mA

61 A solenoid has length 60 x 10 2 m and its total number of turns is 2400 An iron rod is placed inside it along its axis The relative permeability of iron is 1500 If the current in the solenoid be 0 6 A find the magnetic field B and magnetic intensity H inside the rod Calculate the intensity of magnetisation of the Ans 4 52 T 2400 Am 36 x 106 Am rod A

3 Fig 13 3 2 shows a circular motion The radius of the circle the period of revolution the initial position and the sense of revolution i e anticlockwise are The indicated on it corresponding simple harmonic motion of the x projection of the radius vector of the revolving particle P is Tt a x 2 cos 2 c x 2 cos TCt 2 P t 0 2 cm YA FIGURE 13 3 2 b x 2 sin NCERT Based Ttt 2 d x 2 sin Tut 2 T 4s

A bullet losses 1 n of its velocity in passing through a plank What is the least number of plan to stop the bullet Assuming constant retardation A car moving along a straight highu with

5 Two blocks of mass 2kg are connected by massless ideal spring constant k 10N m The upper block is suspended from roof by a light inextensible strings A The spring is initially un stretched The lower block given an initial velocity downwards The minimum tension developed in the string connected to the ceiling is 2m s nearest to 1 10 N A 2kg fee e 2kg 2 20 N

of projection and B p a are projected simultaneously from the same point with the same speed but different angles A The line joining the positions of the particle at any subsequent time makes a constant angle with the horizontal 76 2 4 B The line joining the positions of the particle at any subsequent time makes a constant angle with the horizontal C The magnitude of the relative velocity of the first particle with respect to the second is 2u sin D The magnitude of the relative velocity of the first particle with respect to the co 2 2 2 a B 2 2 a B

44 Twelve wires each having equal resistance r are equivalent resistance between the diagonally opposite to form a cube as shown in figure 32 E20 Find the points a and f h b e C g Figure 32 E20

A planet is moving in an elliptical orbit T U E and L are its kinetic energy potential energy total energy and magnitude of angular momentum respectively then which of the following statement is true 1 T is conserved 2 Vis always positive 3 is always negative OMO L is conserved but the direction of vector L 11

7 A sphere P of mass m and velocity v undergoes oblique and elastic an collision with an identical sphere Q initially at rest The angle between the velocities of the spheres after the collision shall be

The specific gravity of ice is 0 9 Find area in m of the smallest slab of ice of height 0 5 m floating in fresh water that will just support a 100 kg man 200

1 A cup of tea cools from 65 5 C to 62 5 C in 1 minute in a room at 22 5 C How long will it take to cool from 46 5 C to 40 5 C in the same room a 4 minutes c 1 minute b 2 minutes d 3 minutes

5 A variable capacitor has n plates and the distance between two successive plates is d Determine its capacitance n 1 A d Ans C

A current carrying circular loop of radius R is placed in the xy plane with centre at the origin Half of the loop with x 0 is now bent so that it now lies in the yz plane Then NCERT Exempla a The magnitude of magnetic moment now diminishes b The magnetic moment does not change c The magnitude of B at 0 0 z z R increases d The magnitude of B at 0 0 z z R is unchanged

sometimes more than A bar magnet is made to fall through a long vertic copper tube The speed v of the magnet as function of time t is best represented by 1 a 2 b 3 c 1 d V d b a C

2 Two concentric metallic spherical shells are given equal amount of positive charges Then a the outer sphere is always at a higher potential b the inner sphere is always at a higher potential c Both the spheres are at the same potential d no prediction can be made about their potentials unless the actual value of charges and radii are known

An electric dipole has a fixed dipole moment p which makes angle with respect to X axis When subjected to an electric field E E it experiences a torque T tk When subjected to another electric field E 3E j it experiences a torque T T The angle

A ball is thrown vertically upwards with a speed of 10 ms 1 from the top of a 200 m high tower and another is thrown downward with same speed simultaneously from the same point Find the time difference between them in reaching the ground in seconds Bond New Delhi 110005 Ph 011 47623456

29 Find the acceleration of the cylinder of mass m and radius R and that of plank of mass M placed on smooth surface if pulled with a force F as shown in figure Given that sufficient friction is present between cylinder and the plank surface to prevent sliding of cylinder 100 odt 1941 m odtru anillo bod M F P

A block of mass 5kg is moving horizontally at a speed of 1 5 m s A perpendicular force of 5 N acts on it for 4 sec What will be the distance of the block from the point where the force started acting a 2 m b 8 m c 6 m d 10 m

5 AL The group velocity of the de Broglie wave packet associated with a particle moving with velocity v is 1 equal to v 2 less than v 3 greater than v 4 equal to speed of light

KOTA RAJASTHAN 170 In YDSE with two identical slits when upper slit is covered with a transparent sheet of mica second order minima is observed above the centre of the screen and second order maxima below it Which of the following can not be possible value of phase difference caused by the mica sheet 1 FIM 3 2 7 3 10 2 4 11

5 63 A straight thin uniform rod of length 4L and man 4M is bent into a square Its M I about one side is 1 5ML 2 7 ML 3 ML 48 4 ML 3

5 A 13 kg block is initially moving to the right with a speed of 15 m s at the instant shown At the instant shown two forces are also acting on the box a constant 110 N force to the right and a constant 45 N force to the left A What is the acceleration of the block B How much time does it take for the box to speed up to 40 m s 15 m s 13 kg 45 N 110 N

169 Find the torque about the origin when a force of 31 N acts on a particle whose position vector is C for 2km 2 3 4 61 Nm 6 Nm 6 i Nm A 6k Nm i j k 3 2 6 0 1 0 0 kjent

If a current is passed through a circular loop of radius R then magnetic flux through a coplanar square loop of side as shown in the figure l R is 1 3 Mol R 2 l Mol R 26 R l 2 4 Mole 2R MoTR 1

direction An artificial satellite is moving in a circular orbit of radius 42250 km Calculate its speed if it takes 24 hours to revolve around the earth 845

Example 8 22 A man of mass m is standing on a platform mass m kept on a smooth horizontal surface The man star moving on the platform with a velocity v relative to the platform Find the recoil velocity of platform

Carbon silicon and germanium atoms have four valence electrons each Their valence and conduction bands are separated by energy band gaps represented by Eg c Eg si and Eg Ge respectively Which of the following relationships is true in their case 1 E F 2 E E

72 In the following circuit if V A B value of resistance X in ohms will be 1 5 2 10 3 15 4 20 OA www 100 2 V HH 5 V X www m the