Basic Physics Questions and Answers

In the figure shown AB is a rod of length 30 cm area of cross section 1 0 cm and thermal conductivity 336 S I units The ends A and B are maintained at temperatures 20 C and 40 C respectively A point C of this rod is connected to a box D containing ice at 0 C through a highly conducting wire of negligible heat capacity The rate at which ice melts in the box is 10n mg s Find n Given L 80 cal g A C B 20 C 10 cm Ice D 40 C 20 cm Highly conducting wire

Q 117 The acceleration due to gravity g on the Q 117 yet g g GM R where M is mass of earth R is radius of earth surface of earth is g and G is universal gravitational constant If mass of earth decreases by 2 and radius decreases by 1 then percentage change in value of g is 1 Zero 2 2 decrease 3 4 increase 4 4 decrease To M R geat a fava e G fui fe geft an 1 2 fara grada GM R 1 3 4 TI 2 2 4 4 04 al 1 a 1

27 Velocity v of a particle moving on a straight line as a function of time t is given by v 4 t in Sl units Its corresponding distance time x t relation is best shown by K 1 b KL 3 2 Telegram ne

Find a in degrees 3 58 7 Round to the nearest hundredth Ente

20 The current voltage graph for a given metallic wire at two different temperatures T and T is shown in the figure The temperatures T and T are related as 1 2 2 6 wire is it i 2 a Tj T c T T T V T2 b T T d T 2T Which of the following characteristics of electrons rmines the current in a conductor INCEPT Exemp

The velocity of water in river is 9 km hr of the upper surface The river is 10 m deep If the coefficient of viscosity of water is 10 2 poise then the shearing 3 stress between horizontal layers of water is x 10 N m Find x

Q 109 If unpolarised light of intensity 4 W m falls on Q 109 combination of two polaroids having their transmission axis at an angle 90 then intensity of light transmitted 1 Zero 3 2 W m will be 2 1 W m 4 4 W m f 4 W m en af at ga polaroids i firal Eri 1 3 2 W m 0 2 1 W m2 4 4 W m

The rate constant of the reaction A 2 Bis 6 93 x10 2 s 1 If initial concentration of A is 2 M then the time in which B becomes 2 M is 10 s 20 s 10 min hr mi 20 min

The power in an electrical circuit for a current of 5 0 4A and voltage 10 0 2 V measured at 10 error To measure the power at 5 error the current should measured at an error of A 5 B 2 C 10 D 3 E 4

A body moves through a distance of 3 m in the following different ways In which case is the maximum work done a When pushed over an inclined plane b When lifted vertically upward c When pushed over smooth rollers d When pushed on a plane horizontal surface In the above example the work done is mini mum when the body is a pushed over an inclined plane b lifted vertically upward c pushed over the smooth rollers

14 Which of the following diode is used in forward bias for its proper operation Only one correct answer A B LED Review Zener diode

3 A 5 kg block is moving straight across the floor at a constant speed It is being pulled by a force of 30 N as shown in the figure m 5 kg 30 N a How large a friction force impedes the motion of the box b Find u between the box and the floor

x coordinate of a particle moving along x axis 3 t 3t Here x is in metre and t in 3 second The motion starts at t 0 Find acceleration of particle in m s when particle comes to instantaneous rest is x

and block B can move vertically Both are attached by an inextensible string At a certain instant velocity of ring is v and of block is v At that instant ring is at a horizontal distance b from pulley as shown Then A D 0 V b B a A V V cose a a cose where a and a represent the B accelerations of block and ring respectively at that instant C V V cose Angular velocity of the ring with respect Vi sin 0 Va b to an observer on the pulley is

02 The shunt resistance is MENIC of the galvanometer then fraction of the main current that passes through the galvanometer is of 201 3 1 2 Cr 4 of that 5 1 3 n wote 3 2 2 Wires and carrying currents i

A molecule has a dielectric constant of 1 003 The molar volume is 24 5 liters What is the molar polarization N 6 02 1023 Your answer

A particle is moving on a straight line with speed v 30f 4t 2 where v is in m s and t is in s The average speed from t 0 to t 5 s is 1 777 ms 1 2 262 ms 1 304 3 ms 1 4 304 ms 1

The narrow tube AC forms a quarter circle in a vertical plane A ball B has an area of cross section slightly smaller than that of the tube and can move without friction through it B is placed at A and displaced slightly During the motion from A to C it will a Always be in contact A with the lower surface of the tube b Always be in contact with the upper surface of the tube B do c Initially be in contact with the lower surface and later with the upper surface d Initially be in contact with the upper surface and later with the lower surface

Two wires have lengths and and carrys equal currents Two circular loops are made by these wires and the ratio of their magnetic moment is 3 2 Then the ratio of lengths of wires is 1 9 4 2 4 9 3 3 2

Equal volumes of water and aliquid when put in similar calorimeters take 100 sec and 80 sec respectively to cool from 50 Cto 40 C The thermal capacity of each calorimeter is numerically equal to the volume of either liquid The specific gravity of alcohol is 0 9 if the specific heat capacity of water is 1 cal gm C the specific heat capacity of liquid will be 1 0 6 cal gm C 2 0 8 cal gm C 3 0 667cal g C 4 1 8 cal gm C

AK transition photon emitted by one hydrogen atom strikes a second hydrogen atom in ground state an undergoes photoelectric absorption with an L shell electron What energy does the ejected electron have A 13 6 eV C 3 4 eV B 10 2 eV D 6 8 eV

8 A transistor connected in CE mode has a current gain of 50 If the load resistance is 5 K input resistance is 1 K and the input peak voltage is 0 4 V then the peak output voltage will be a 25 V c 75 V b 50 Vla d 100 V

PHYSICS A vessel is filled with a non homogeneous liquid till height H 10 cm whose refractive index varies with the depth y from the free surface of liquid as 1 10 here y is in cm If the apparent depth as seen by an observer from above is H then value of H take In 2 0 7 H in cm is

The average value of the output voltage for one complete cycle of half wave rectifier is Given input voltage V Vo sin wt R 2 Zero 2V

A ray of sunlight enters a spherical water droplet n 4 3 at an angle of incidence 53 measured with respect to the normal to the surface It is reflected from the back surface of the droplet and re enters into the air The angle between the incoming and outgoing ray is Take sin 53 0 8 A B C 15 34 138 Correct Answer

For the astronomical telescope four lenses of focal length 10 cm 10 cm 100 cm and 100 cm are available The focal length of objective lens for maximum magnification should be 10 cm 10 cm 100 cm 100 cm

MP 4 5 6 A saw is used to make a notch in a 20 centimeter tall piece of wood It cuts down a centimeter for every centimeter it moves to the right until it has moved down 16 centimeters the desired location of a notch It then moves up a centimeter for every centimeter it moves to the right a Graph the saw position function first in order to recognize it The input of the function x is the distance that the saw has moved to the right and the output of the function f x is the height of the cut from the bottom of the piece of wood

12 When n cells are joined in parallel combination shown the strength of the current i is given by a c nE R nr E r Rn R E r H E r E r K E R r n d None of these b

The on x OL represer 1 S H M with amplitude A 2 Periodic motion with amplitude 3 Oscillatory motion with angular frequency AN HAIRY 1 2 3 at ang at f gal

sion For Q Nos 22 to 24 The arrangement shows a point object O placed on the axis of a thin convex lens of focal length 20 cm A sharp image is obtained behind the lens It is found that if O is displaced along a line perpendicular to axis by a distance of 1 cm I moves by 2 cm Answer the following questions te C A f 20 cm B B axis 22 If the object is displaced by 0 01 cm towards C along axis of the lens I moves 1 Away from C along the axis by 0 02 cm 3 Away from C along the axis by 0 04 cm 2 Towards C along the axis by 0 02 cm 4 Towards C along the axis by 0 04 cm

11 Two non ideal batteries are connected in series Consider the following statements A The equivalent emf is larger than either of the s B The equivalent internal resistance is smaller than emfs either of the two internal resistances a Each of A and B is correct b A is correct but B is wrong c B is correct but A is wrong d Each of A and B is wrong

Q 180 Consider the following reaction Mx MnO MO Mn If 1 mol of MnO oxidises 1 67 mol of M to MO then the value of x in the reaction is 1 2 3 4 2 3 4 5 Q 180

on one of the equal faces of an isosceles glass prism The light ray is reflected internally twice on the same sized faces and then emerges through the base of the prism perpendicularly then choose matching List I P Prism angle A Q zB or C R Deviation at face AB S Deviation at face AB Codes P Q 2 A 1 R 3 2 S 1 1 90 B 4 List II 1 36 2 72 3 108 4 144

A disc of mass m radius R is rolling on a rough surface of sliding encounter with a movable wedge as shown in figure there is no friction between wedge and ground and also between disc and wedge then A Maximum height attained by the disc centre is v 4g B Velocity of wedge when disc reach maximum height v 4 C Angular velocity of disc at maximum height will be zero D Velocity of disc at maximum height will be zero V R

A uniform conductor of length is connected as shown in the figure The distance of the pointer of the galvanometer from end A so that there is no deflection in it will be A B C Zl 38 49 4 5T B

A light of wavelength 5000 is incident on a metallic surface of work function 2 eV The maximum kinetic energy of photoelectrons will be nearly 0 4 eV 0 5 eV 0 48 eV

A man is sitting in a boat which is floating in a pond If the man drinks some water from pond the level of water in pond Q ncp 1 Increases 2 Decreases 3 Remains unchanged S 4 Increases or decreases depending on densit of water Q NX 7 2 2

The system is released from rest with both the springs in unstretched position Mass of each block is 1 kg and force constant of each spring is 10 N m Assume pulleys and strings are massless and all contacts are smooth g 10 m s mA mmmm IR A Extension of horizontal spring in equilibrium is 2 5 m B Compression of vertical spring in equilibrium is 1 5 m C Maximum speed of the block A is 28 m s D Maximum speed of the block A is 14 m s

Two beads of equal mass m and unlike charges of modulus q and q can slide on a fixed frictionless non conducting rod bent at right angle Initially the beads are held at rest at distances d and 2d from the corner as shown and then released simultaneously When one of the beads reaches the corners where will the other bead be from corner Treat the beads as particles A 2d B d 9 2d 55d 92 d D zero

A small body of unknown charge travelling 6 1 x 105 m s enters a 0 40 T magnetic field directed perpendicular to its motion a If the particle experiences a force of 9 0 x 10 N what is the magnitude of the charge b If the object is sent into the magnetic field so that its velocity makes an angle of 30 0 with the magnetic field by how much will the magnetic force be reduced

A groove is in the form of a broken line ABC and the position vectors of these three points are respectively 21 3 2k 31 2j k k A force of magnitude 24 3 acts on a particle of unit mass kept at a point A and moves it along the groove to the point C If the line of action of the force is parallel to the vector i 2j k find work done by the force all quantities are in SI units A 144 2 B 144 3 C 72 2 D 72 3 8

A uniform rod AB of length is rotating with angular velocity o while its centre of mass moves with linear velocity of v w 6 If the end A of the rod is suddenly fixed then angular velocity of the rod will be B 3 1 20 4 3 2 E K mul 2 Ald Fixed V 2 4 3 3 4 8 IW mive mive me 2 3 wel YEA 3 w 2 4 x w

197 Select correct statement about pure rolling of a spherical body symbols have usual meanings 1 Distance moved by any point on the periphery of the body in one rotation is 2 R 2 v wR is always applicable on a rolling body C 3 Point of contact is the instantaneous centre of rotation in pure rolling 4 All of these

Two vectors P and Q are added the magnitude of resultant is 15 units If Q is reversed and added to P resultant has a magnitude 113 units The resultant of P and a vector perpendicular to P and equal in magnitude to Q has a magnitude A 13 units C 19 units B 17 units D 20 units

Displacement PP Displacement A displacement distance graph of a sound wave is given then what is the corresponding displacement time graph among the following Take wave velocity as 320 m s Displacement 7 mm Displacement B Distance b Time s Time us Time us

If instead of mass length and time as fundamental quantities we choose velocity and force as fundamental acceleration quantities and express their dimensions by V A and F respectively then the dimensions of pressure p will be as expressed as A FA V 4 B F V A C FA V D FAV 2

Q 179 A solid having density of 9 x 10 kg m forms Q 1 face centred cubic crystals of edge length 200 2 pm What is the molar mass of the solid 1 0 0432 kg mol 3 0 4320 ka molit 2 0 0305 kg mol

Paragraph for Question Nos 17 and 18 In the shown AC circuit reactance of capacitor and inductor are shown in figure Current 1 12 13 and I are also shown in figure Answer the following questions on the basis of above information S 4 1 2 7 If the switch S is kept open then A 10A B 10A C 10 2A D 20A 18 When the switch S is closed then A 10A C 3 8A XF 892 www R 80 R 10 20 www R 802 mm X 89 V 80 2 Volt B 10A D 18A

English At temperature 23 C the resistance of a wire is 100 Q The temperature at which resistance becomes 104 Q is nearly Given temperature coefficient of resistance of materia 5 10 4 C O 1027 C O 827 C O 290 C 0 290 K View in

Two nucleons are at a separation of 1 x 10 15 m The net force between them is F if both are protons F if both are neutrons and F3 if one is a proton and other is a neutron In such a case 1 F F F3 2 F F F3 3 F F3 F 4 F F F3