Basic Physics Questions and Answers

A particle is projected horizontally from top of an incline Incline makes 37 angle with horizontal At the same time a float trolley is released from a point 3 m down the incline wi goes down starting from rest at acceleration of gsin 37 If the particle lands in the trolley the speed with which the particle is projected 3m 37

A rectangular frame of area 10 m is placed in a uniform electric field of 20 N C with normal drawn on the surface of the frame making 60 angle with the direction of field The electric flux through the frame is b 200 Vm d 100 3 Vm a 100 Vm c 50 3 Vm

Consider a cone with half angle a is placed such a way that vertex is at origin and its axis is along z direction Obtain the expression for radial acceleration of a particle of mass m is constrained to move on the surface of the cone by taking Lagrangian in terms of spherical polar coordinates r and o Assume 1 is the angular momentum along direction a b c 1 2 sin a 12 mr 23 m r sin a 1 2 2 m r sin a 12 g cos a g cos a gcos a o cos a

1 Water is poured in a thin vertical uniform tube and the water levels are initially as shown in figure The lower portion of the tube is a semi circle of radius R The water is left free from rest as shown in figure If density of water is p gauge pressure at A in the water just after the release is A Pa C ogh R atmosphere A B pgh D pgh 0 R h h nR OF PHYSIC B

A transverse sinusoidal wave is generated at one end of a long horizontal string by a bar that moves with an amplitude of 1 12 cm The motion of the bar is continuous and is repeated regularly 120 times per second The string has linear density of 117 g m The other end of the string is attached to a mass 4 68 kg The string passes over a smooth pulley and the mass attached to the other end of the string hangs freely under gravity Read the above passage carefully and answer the following questions 7 The maximum magnitude of the transverse speed is A 10 884 m s C 844 m s B 8 44 m s D none of these

51 Electromagnetic induction occurs in a coil when there is a change in 1 Electric field intensity in the coil 3 Voltage in the coil 52 Which of the following is not a convex lens 2 Magnetic field intensity in the coil 4 The coil s polarity

In the loop shown in fig all curved section are either semicircular or quarter circles All magnetic field at the centres have magnitude B B B3 and B a AXOM a B4 b B B is maximum B3 is minimum R RR R

Q 26 A ball is thrown upwards from the foot of a tower The ball crosses the top of tower twice after an interval of 4 seconds and the ball reaches ground after 8 seconds then the height of tower is g 10 m s m

A ball of mass 0 1 kg is thrown against a wall It strikes the wall normally with a velocity of 30 m s and rebounds from there with a velocity of 20 m s The impulse of the force exerted by the ball on the wall is 1 0 5 Ns 2 50 Ns 3 1 Ns 4 5 Ns

A bus is moving on a straight road with constant velocity v A boy standing in an adjoining meadow spots the bus and hopes to get a ride on it What is the minimum speed with which the boy must run so that he manages to catch the bus Also find the corresponding direction a cart road

28 All the surfaces are frictionless Strings are light and frictionless The tension in string 1 is Take g 10 m s 2 1 3kg Biss 1 kg 7777 mainsmoal Isonde w the 1 O 4

27 A rod of length 10cm made up of conducting and non conducting material Shaded part is non conducting The rod is rotated with constant angular velocity 10 rad s about point O in constant magnetic field of 2T as shown in the figure The induced emf between the point A and B of rod will be A 0 029 V B 0 1 V C 0 051 V D 0 064 V 2cm

A metallic sphere of radius 1 cm in air is given a charge of 1 coulomb Electric potential at the surface of sphere will be X9x10 1 V 9x10 V Zero Sphere cannot hold this charge Solution Answer 4 E KQ 9 10 x1 R 10 4 9x10 3 V m

A symmetrical 5 khz square wave whose output varies between 10V and 10V is impressed open clippling circuit shown in figure If diode has R 002 and R 2m2 and V 0 What is output waveform K 2 5V IMQ

Figure shows a siphon the vessel area is very large as compared to cross section of tube Tube has a uniform cross section its lower end is 6m below the surface of water What is maximum height H in m of the upper end for siphon to work Take density of water 10 kg m atmospheric pressure 105 N m D 6m H

graph shows how the reciprocal of magnification produced by a coneverging thin lens varied with object distance u in displacement method What was the focal length of the lens used H 1 a b 2 bc a 3 c b 4 ab c a b IS piaced

30 A 0 1 m long conductor carrying a current of 50 A is perpendicular to a magnetic field of 1 25 mT The mechanical power to move the conductor with a speed of 1 m s is C 0 625 W A 0 25 mW B 6 25 mW D 1 W

10 In a screw gauge each main scale division is 1 mm and there are 200 divisions on the circular scale The least count of screw gauge is NCERT Pg 35 1 0 05 mm 2 0 005 mm 3 0 05 cm

m e 4 e om 15 A light bulb and a capacitor are connected to an ac source through key as shown in the figure below The key is closed and after some time dielectric material is inserted between the plates of the capacitor The brightness of light bulb C up 18 S Z 7x Z 7KI Yok B B 1 Increases 2 Decreases 3 Remain unchanged 4 Will fluctuate alay 2

A fighter plane flying horizontally at an altitude of 2km with a speed of 540km h passes directly overhead an anti aircraft gun If the gun can fire a bullet at the muzzle speed of 500m s at what angle with the vertical should the gunfire so that the bullet hits the plane A cos B sin 1 C tan 1 3 10 3 10 3 10 1 D tan 1

Pure Germanium has a resistivity of 4 22 m The mobility of electrons and holes in Ge are 0 4 m Vs and 0 2 m Vs respectively A sample of Ge is doped with 1022 m of Boron The concentration of electrons and holes are respectively in m A 6 76 10 4 1022 B 1022 6 76 10 4 C 6 76 1020 1022

31 Magnetic flux linked with a stationary loop of resistance R varies with respect to time during the time period T as follows at T 1 The amount of heat generated in the loop during that time 0 to Ts inductance of the coil is negligible is a T a T4 3R B 3R A C a T 6R D a T 3R

I have understood the solution but I am not able to under stand how the encircled equation is derived and through w nich formula it has come Kindly help teachers will be evergrateful to you Example 5 Strategy Solution A very long thin sheet carries a current i along its length The current is uniformly distributed across its cross section This sheet is bent so as to form a hollow hemi cylindrical surface Find the magnetic field on the axis of this half cylinder Take the radius as R axis The figure shows the cross section of the sheet Consider an arc of length ds which subtends an ido xdS T angle do at the centre The current flowing across the length of this arc is di TR y axis dS Rdo dB is the magnetic field due to the arc then AB Ma dB Hodi 2 R dB Hodi 2nR B dB B B Ho in the direction shown 2n R sinoi cosoj DICE 0 121 0 H i i L R singdai cosode di de do 50000 199 dB dS x axis Onkoch Tower 8 Pusa Road New Delhi 110005 Ph 011 47623456

7 An elevator is designed to lift a load of 1000 kg through 6 floors of a building averaging 3 5 m per floor in 6 sec Power of the elevator neglecting other losses with be 1 3 43 x 10 watt 2 4 33 x 104 watt 3 2 21 x 104 watt 4 5 65 x 104 watt 8 A convex lens and a concave lens are kept in contact with common principal axes If f and f

A small body of density p is dropped from rest at a height h into a lake of density p where p Which of the following statement or statements is or are correct if all dissipative effects a neglected neglect viscosity A the speed of the body just entering the lake is 2gh B the body in the lake experiences upward acceleration equal to p p 1 g the maximum depth to which the body sinks in the lake is hp p p D the body does not come back to the surface of the lake 1

1 Election will be held for every years A FOUR B FIVE C TWO D THREE 2 How many assembly constituency in AP A 175 B 294 C 250 D 25 4 A AndhraPradesh B Karnataka C Telangana D Tamilnadu 5 Railways Track is Symbol A B A C D 6 Capital City Of Gujarat A Goa B Gandhi Nagar C Rajasthan D Gandhi Street 7 How many State in INDIA D 30 3 Expand MLA A Member of law Account B Member of Legistative Assembly C Member of Legistative Act D None Evergreen Forest in Westren Ghates located in INDIA A 27 B 28 C 29 8 The Fertile Deltas are formed by A Lakes B Seas C Oceans D Rivers 9 Shifting Agricuture is known as A Nadu B Nedu C Podu D Eenadu 10 Howmany Seasons is European Countrie A Four B Three C Five D Two

Mention the reason for the approach Explain the cause of the tension at the lowermost point if we take torsional balance about the center of on side of th e string the resultant tension should be zero as there is a n equal force to balance torque on the other side PLS EXPLAIN HOW DO FIND TENSION AT ANY OTHER POIN T SOLVE 26 A rope of mass 5 kg is hanging between two supports as shown The tension at the lowest point of the rope is close to take g 10 m s 30P M A 22 N B 44 N C 28 N

3 the body has lost some electrons 2 The force of gravity on a body mass W is 1 W 2 Wg TT TI 4 the body has lost some protons 3 W g 4 W x g

37 A body moving with a velocity of 4 m s possesses 56 J of kinetic energy The momentum of body will be equal to 1 7 kgm s 3 21 kgm s 2 14 kgm s 4 28 kgm s

and current II Motional emf v Bul e 2 DWD at right angles to the horizontal Example 16 A horizontal straight wire 10 m long extending from east to west is falling with a speed of 5 0 m s component of earth s magnetic field equal to 0 30 x 10 4 Wb m 2 a What is the instantaneous value of the emf induced in the wire What is the direction of emf c Which end of the wire is at the higher electrical potential Solution a Instantaneous emfe BH vl Given BH 0 30 x 10 NCERT Problem 6 7 Tu 5 0 ms 1 10 m e 0 30 x 104 x 50 x 10 1 5 x 103 V 1 5 mV b By Fleming s right hand rule the direction of induced current in the wire will be from west to east therefore direction of emf will be from west to east c The direction of electron flow will be from east to west The induced emf will oppose the flow of electrons from east to west so eastern end will be at a high otential int of earth s magnetic field be

Question No 29 The speed of a wave in a certain medium is 1080 m s If 1800 waves pass over a certain point of the medium in 30 seconds then wavelength of the wave O 12 m O16 m 18 m 22 m

The work done by the system in the cyclic process as shown in figure is V cm 500 300 10 J 40 O 3 14 J O 8 43 J O Zero 60 in kPa

Metals Threshold frequency x1014s 1 A IB C D 5 2 3 8 4 6 5 8 The metal having the highest kinetic energy of photoelectrons on irradiating with light of frequency

Jon No 24 A particle perform SHM of amplitude A along a straight line When it is at a distance of A from its mean position Its kinetic energy gets increased by an amount 2 mu A due to an impulsive force The new amplitude of the particle becomes 2 2 A 312 A 52

13 A solid spherical ball of mass M and radius R rolls without slipping down a surface inclined to horizontal at an angle 45 Considering that ball is uniform solid sphere and that ball and surface are perfectly rigid Match Column I and Column ll Column l A Reaction force B Friction force C Contact force D Net force s t Column II s Mg 53 7 2 Mg 9 2 5 7 2 2 Mg Mg t Electromagnetic

The magnetic flux linked with a coil is given by the equation 61 2t 10 Wb Then A the magnitude of emf induced in the coil at 4 sec is 250 V B the induced current in the coil at the 20 sec if the resistance of the coil is 100 is 7A C the average charge flowing through the coil in the first 2 seconds is 4 40 D none of these

A just tight inextensible string of length connects two masses m and 4m and the system rests on smooth horizontal floor An impulse J is imparted to B as shown in figure The tension in the string in the subsequent motion is Am 8 4m ml j 5ml

For series L C R AC circuit shown in figure the readings of V and V3 are same and each equal to 100 V Then wwwmoo V V 200 V 50 Hz V3 a the reading V is 200 V b the reading of V is 0 c the circuit is in resonant mode and resonant frequency is 50 Hz d the inductive and capacitivo d capacitivo reactance are equal

A NPN transistor connected in common emitter configuration is shown below If R 8 6 k R 100 2 VE 0 7 V B 100 then calculate VCE BE 5V dok R wwwwww B O C E R www F10V AT Y

The two waves having intensities in the ratio 1 9 produce interference The ratio of the maximum to the minimum intensities is equal to 81 1 3 1 4 1

A football player kicks a ball for a goal at an angle with the ground In the presen of air resistance the horizontal velocity of the ball a a changes throughout the path due to gravity b b is zero at the top of the path c c decreases throughout the path d d remains constant throughout the path

15 A diatomic ideal gas undergoes a thermodynamic change according to the P V diagram shown in figure The total heat given to the gas is nearly 1 2 5PoVo 3 3 9PoVo PA 2Po Po A Vo Isothermal C V 2V 2 1 4P Vo 4 1 1PV

Read the description about the following genius Indian personalities and write their names 1 6 Metro Man Brain behind the Delhi Metro groedharan 4 Second youngest climber of Mount Everest at the age of 15 years 7 months Roy Rachan Joneja India born American Scientist awarded the Nobel Prize in Chemistry 2009 2 Performed first robot assisted heart surgery CLUE BOX E Sreedharan Durba Banerjee Raghav Joneja Balamurali Ambati Sudhir P Srivastava Venkatshwar Ramakrishan 7 MC Modi Vijay Bhatkar The world s youngest doctor 3 5 Man behind India s first super computer Param vijay Bhatkan 8 Holds the record for maximum flying hours by a woman pilot Performed maximum eye operations at the rate of 40 operations per hour

Equation of a travelling wave on a string is given by T y 10 sin 4rt 10 sin 4 X If x and y are in centimetres then 16 velocity of wave is 32 cm s in positive x direction 64 cm s in positive x direction 32 cm s in negative x direction 64 cm s in negative x direction

6 The angular momentum of a body having linea momentum P 2 3 4k at 1 0 2 abou the point 2 3 4 is given by 1 21 61 3k 2 61 3k 3 6i 3k 4 21 41 6k

In the figure shown amount of heat supplied to one mole of an ideal gas is plotted on the horizontal axis and amount of work done by gas is drawn on vertical axis Assuming process to be isobaric thegas can be W J 32 30 20 10 O O 20 40 60 80 He CO CO Q J

One end of the pile of chain falls vertically through a hole in its support and pull the remaining links steadily The links which are at rest acquire the velocity of the hanging position suddenly and without having interaction with the remaining stationary links and with the support If the acceleration a of the falling chain is g k Find k Ignore any friction

gauge whose least count is 0 005 mm the 5 th division on its circular scale overlaps with the reference line on main scale and when a small sphere is placed then reading on main scale advances by 4 divisions whereas circular scale reading advances by five times to the corresponding reading when no object was placed There are 200 divisions on the circular scale The radius of the sphere is O O 4 10mm 4 05 mm 2 10 mm 2 05mm

1 A liquid is flowing in a horizontal pipe of uniform cross section at a speed v Two tubes A an B are inserted into the pipe as shown Assume the flow to remain streamline inside the pipe B h h a The diagram depicts that height of liquid in tube B h is more than the height of liquid in tube A h Is it correct b Calculate the difference in height of the liquid in two tubes

When we pull a table cloth out swiftly the table cloth may be removed withou disturbing the dishes placed on it This is due to the principle of a a Inertia of rest b b Inertia of motion c c Inertia of direction d d Newton s third law