Basic Physics Questions and Answers

In the figure shown water is filled in the cylindrical tank of cross sectional area 100 cm up to a height of 10 cm The mass of the thin tight fitting and frictionless piston is 100 kg The small hole in the piston has area 2 2 mm Due to weight of the piston water spurts upwards in a jet from the hole Find the time in sec in which the tank becomes empty Assume that spurted water does not fall back on piston

Q2 When the pump in Fig below draws 220 m h of water at 20 C from the reservoir the total friction head loss is 5 m The flow discharges through a nozzle to the atmosphere Estimate the pump power in kW delivered to the water Water 2m 6 m D 12 cm Pump De 5 cm

6 Twelve resistors are arranged into a cube as shown in figure All resistors have a resistance of 602 A 25 V potential difference is applied from point A to point D Find the total current flowing from A to D A 1 IA www www www www www 2 2A www ww www D 3 SA 4 10A

The breaking tension of a string is 10N A particle of mass 0 1 kg tied to it is rotated along a horizontal circle of radius 0 5 meter on a smooth horizontal surface The maximum speed with which particle can be rotated is O 5 m s O V 50 m s O 500 m s 1000 m s

A circuit connected to an ac source of emf e e sin 100t with t in seconds 4 gives a phase difference of between the emf e and current i Which of the following circuits will exhibit this A C D RC circuit with R 1 kN and C 10 F RC circuit with R 1 k and C 1 F RL circuit with R 1 k and L 10mH RL circuit with R 1 k2 and L 1mH

A disc of mass m is released from top of inclined plane of slope a as shown in fig If u is the coefficient of friction between disc and plane surface Choose the correct statements CORE 13 tar If h tana the acceleration of disc along plane is g sina 3 tana the net force acting on disc is 2mg sina 3

A ball is held at rest in position A by two light cords The horizontal cord is now cut and ball can swing in vertical plane What is the ratio of the tension in cord OB in position B to that in position A cord OA originally Before cut 43 60 60 B

4 g calcium is dissolved in hydrochloric acid at 27 C in an open vessel at the atmosphere pressure 0 821 atm The work done is 1 O 2 24 94 litre atm 3 2 463 litre atm 4 0 0821 litre atm

SolveLancer Test An object projected vertically up from the top of a tower then find ratio of distance travelled by it in the last second and distance travelled by it in the last 2 second of its motion SolveLancer Test a 1 2 b 2 1 c 1 4 d 4 1

15 A liquid having small depth but large volume is forced by an applied pressure p above it to escape with velocity v through a hole below If v is given by v Kpa pb where p is the density of liquid and K a and b are dimensionless constants Calculate the values of a and b If v 14 ms p 1 0 x 105 pa and p 10 kg m 3 calculate the value of K

Q 15 Figure shows a circular region of radius R 3 m which has a uniform magnetic field B 0 2 T directed into the plane of the figure A particle having mass m 2g speed v 0 3 m s and charge q 1mC is projected along the radius of the circular region as shown in figure Calculate the angular deviation produced in the path of the particle as it comes out of the magnetic field Neglect any other force apart from the magnetic forma X X X X X X X X 0 x X X X X X X

1 kg a b c 2 kg Smooth 3 kg 30 F 60 N Column I Acceleration of 2 kg block Net force on 3 kg block Normal reaction between 2 kg and 1 kg d Normal reaction between 3 kg and 2 kg O a s b r c q d p Oa r b t c q d t Oa s b p c q d r Oa r b q c r d p Column II p 8 SI unit q 25 SI unit r 2 SI unit s 45 SI unit t None

3 2 0 4 2 6 44 A force F B k acts at point O the origin of the co 44 ordinate system What is the torque of this force about point P 2 3 1 2B1 381 2 Bo3 i 1 4 381 28 1 3 4B 1 1 45 A Diwali rocket move vetically up with the constant 3 2 0 4 2 6 ya farfa f for P 2 3 aqui a F Bo k fa u 1 2B1 3Boj 3 4B i 1 2 B 3 i j 4 3B1 2B1 20

The state of the system in terms of the orthonormal vectors and 3 is 3 2 u 54 59 14 The Hamiltonian of the system is n s 1 10 Here n 1 2 and 3 and has the dimensions of energy Calculate the average energy of the system a 2 484 b 0 177 2 484 c E d

Two block of same mass m are joined with an ideal spring of spring constant k and kept on a rough surface as shown in figure The spring is initially unstretched and coefficient of friction between the blocks and horizontal surface is u and 2 respectively What should be the maximum speed of block A such that the block B does not move m A 2m 249 K 2m 449 K K m k roooooo m B 2

wo conductors A and B each of cross section area 5 cm are connected in series Variation of temperature in C along the length in cm is as shown in the figure If thermal conductivity of A is 120 J m sec C The thermal onductivity of B is 40K J m sec C Find the value of K

An empty vessel of cross sectional area A is being filled using a tap through which water is coming out at a rate of a m s The vessel has a hole of area a at the bottom as shown in the figure Determine height h of the water in the container as a function of time t Area A am s Area

In the given circuit directions of current flow in branches BF and CE are R www ww R B www www R 1 B to F and C to E 3 B to F and E to C Ww R www www R 2 F to B and C to E 4 F to B and E to C

5 A spherical shell is uniformly charged by charge q A point charge q is at its center The work of electric force upon the expansion of shell from R to 2R is 3 3q 16m R 16 R 2 4 Sme R 4x2 R

6 The ammeter reading for the following circuit shall be maximum when the value of variable resistance R shall be 10v 1 R 122 2 R 0 502 www 102 R 3 R behaves as connecting wire of negligible resistance

Current varies in a coil as i 2 3 At f 1 s a voltage of 30 volts is induced in another coil which shares the flux with the first coil Find the mutual inductance between the coils in Henry

17 Four rods each of length I have been hinged to form a rhombus Vertex A is fixed to a A rigid support vertex C is being moved along the x axis with a constant velocity v as shown in the figure The rate at which vertex B is approaching the x axis at the moment the rhombus is in the form of a square is a b d 3 2 B V X

2 A 10 g bullet with a horizontal velocity of 300 m s hits a wooden block of mass 290 g After collision the block and the bullet move together and come to rest after travelling 15 m horizontally What is the coeffi cient of friction between the block and the horizontal plane on which it is kept 0 34

3 48 4 4 Spol 2 0 45 A Diwali rocket move vetically up with the constant 20 accleration a m s After same time its fuel gets exhausted and then it falls freely with an accleration a 10 m s Find it speed v when its fuel just gets exhausted if maximum height attain by it is 50 m 1 20 m s 2 30 m s 3 40 m s 4 50 m s 3 4B0 4 45 va facial data gia 1 20 m s 2 30 m s 3 40 m s 4 50 m s 4 pol Pol 20 are an are fred m s TO a 10 m s fal 50 a zara et i

A short dipole of dipole moment rod with linear charge density at a distance r Find axis perpendicular to a long thin uniformly charged the force acting on the rod due to field of dipole 1 p 2 EO p 3 2 p TEO 3 r Its p

plates is 104 volt If the plates are separated by 0 5cm the force on an electron between the plates is 1 3 2 10 5 N 3 3 2 10 N 2 6 4 10 N 4 6 4 10 5 N

30 A single cylinder four stroke engine has a bsfc of 1 13 x 10 5 kg kW h and a fuel consumption rate of 0 4068 kg h The specific power output of the engine is 0 33 kW cm2 If the engine runs at 3000 rpm find the displacement volume of the cylinder and if the 3p is 15 m s find the bmep

Figure shows a network of eight resistors each equal to 202 connected to a 3V battery of negligible internal resistance The current I in the circuit is 1 0 25A 3V 2 0 5A

If magnetic field in space is IT electric fi is 10 N CI no gravitational field is present a charged particle is released from rest fr origin it will 1 not move at all 2 move in circular path 3 move in a helical path 4 more on a straight line

Given below are some functions of x and t to represent the displacement transverse or longitudinal of an elastic wave State which of these represent 1 a travelling wave ii a stationary wave or iii none at all a y 2 cos 3x sin 10t b c d y 2 x vt y 3 sin 5x 0 5t 4 cos 5x 0 5t y cos x sin t cos 2x sin 2t

A charge of 3 14 106 C is distributed uniformly over a circular ring of radius 20 0 cm The ring rotates about its axis with an angular velocity of 60 0 rad s Find the ratio of the electric field to magnetic field at a point on the axis at a distance of 5 00 cm from the centre In a hydrogen atom th

A small hole is made at the bottom of a symmetrical jar as shown in figure Liquid is filled into the jar upto a certain height The rate of descension of liquid is independent of the level of liquid in the jar Then the surface of jar is a surface of revolution of the curve y O y kx Oy kx O y 3 y kx X

In the given circuit switch S is closed and when steady state is reached switch S is also closed The charge on 6 F capacitor will be S S 20 V 1 20 C 6 F HH 3 F S 10 V

When 0 50 X rays strike a material the photoelectrons from the K shell are observed to move in a circle of radius 23 mm in a magnetic field of 2 x 10 2 T The binding energy of K shell electrons is a x 100 eV then write the value of a in your OMR sheet Take mass of electron 9 2 x 10 31 kg hc 12400 eV

Take 0 cot 2 Neglect the toppling of wedge Graph shows variation of internal energy U with density p of one mole of an ideal monoatomic gas Process AB is a part of rectangular hyperbola Find work done in the process in Joules Ujoule 23 20 A radioactive nucleus X decays into a nucleus Y which itself is radioactive Y decays into a stable nucleus Z

1 The total flux associated with the given cube will be where a is side of the cube 4 9 10 SI units 0 62 x 10 Nm C 62 x 10 Nm C 62 x 10 6 Nm C 4 C 2 C 6 C 8uC a a 1 C 3 C ZUC CO 05

An equation y acos 2 nt a 2 colo st wave with amplitude a frequency n and wavelength 2 amplitude a frequency 2n and wavelength 22 a represents 3 amplitude frequency 2n and wavelength A K 4 amplitude frequency 2n and wavelength 4409

Two point charges Q and Q 2 are placed on the x axis such that Q is at the origin and the other Q 2 is at x 4cm A third charge Q is placed on x axis so that the potential energy of the three charge system is same as the potential energy for the infinite separation The x coordinate of Q is approximately 1 10 cm 3 13 cm 2 17 cm 4 7 5 cm

A total charge q passes through a resistor of resistance R The current decreases continuously such that it qlog 2 2T becomes half after every time T If the initial value of the current is i k Find the value of k R www

A long thin rod lies along the x axis with one end at the origin It has a uniform charge density C m Assuming it to be infinite in length the electric field at the point x a on the x axis will be 2 2 1 2 E 2 3 4 E 2 4 22

The inside of a grounded spherical metal shell inner radius R and outer radius R is filled with space charge of uniform charge density p M The electrostatic energy of the system is The electrostatic energy the system is The potential at the center is PR fifr 2mp R5 45 0 2 R 25 0 R P Metal R D

57 Two charges q 92 12x10 C are placed 10cm apart The potential at a point 6cm from q on the line joining the two charges is 1 3500 Volt 3 1800 Volt 2 900 Volt 4 900 Volt

3 The graph which depicts the results of Rutherform gold foil experiment with a particales is 0 Scattering angle Y Number of scattered a particles detected Plots are schematic and not to scale 1 2 3 4 0 0 01

A combination of two simple harmonie motions with arbitrary amplitudes and phases is not necessarily periodic It is periodic only if frequency of one motion is an integral neltiple of the other s frequency However a periodic motion can always be expressed as a Sum of infinite number of harmonic motions with appropriate amplitudes The period of SHM does

A charge of mass m and charge q is accelerated from rest in a uniform electric field of strength E The velocity acquired by it two second after released will be O O2qE m J4gE

A ray of light AO in vacuum is incident on a glass slab at angle 60 and refracted at angle 30 along OB as shown in the figure The path length of light ray from A to S O o Varuum glass 2 3 a O2a O2a 2b Alm 2b 3 O2a 2b

The work done in Joule in carrying a charge of 100 coulomb between two points having a potential difference of 10 volt is 1 0 1 3 100 2 10 4 1000

In the figure shown two long straight wires with the same cross section are arranged in air parallel to one another The distance between the axis of the wire is n times larger then the radius of wire s cross section Capacitance of the wires per unit length would be Take n 1 a b way for 1 and for at vis aften erft n 11 2n 0 in n IE 2 Inn RE Top view of the arrangement P

atter 24 A pendulum clock made of metal gives correct 37 Abl time at 30 C If the room temperature rises to 40 C then error in the clock per 10 hours would be 10 C wa 1 40 s 2 120 s Ar 10 3 180 s 4 240 s A black body at 327 C suspended in a black

A string of mass m is fixed at both ends The fundamental tone oscillation is excited in the string with angular frequency and maximum displacement amplitude A The total mw A where x is an integer from zero to 9 Find x energy contained in the string is