Basic Physics Questions and Answers

2 27 For a particle moving variation of its acceleration a as a function of time t is as shown Variation of its position x with time t is best represented by 2 KF 1 3

2 36 A steel scale calibrated at 25 C has been employed to measure the length of a copper pipe at 25 C However the reading has been taken at 65 C If thermal coefficient of linear expansion of steel and copper are 3 x 10 5 per C and 2 x 10 5 per respectively then percentage error in reading taken is 1 0 01 3 0 04 2 0 02 4 0 05

40 In the circuit shown the power consumed by the bulb B long time after the key K is closed is inductor is ideal B 50 10 volt 1 5 W L 5 mH K B 502 2 10 W 3 20 W 4 40 W

73 Two resistances are connected in two gaps of a meter bridge The balance point is 20 cm from the zero end A resistance of 15 2 is connected in series with the smaller of the two The null point shifts to 40 cm The value of the smaller resistance in ohm is t y a 3 c 9 e None of these b 6 d 12 5 6 is used

2 32 From a suitable height two projectiles are thrown simultaneously in a horizontally opposite direction with equal speed 20 m s Then the time after which the projectiles will be moving perpendicular to each other is g 10 m s 1 1 s 3 3 s 2 2 s 4 4 s

54 A 100 V voltmeter of internal resistance 20 kn in series with a high resistance R is connected to a 110 V line The voltmeter reads 5 V the value of R is a 210 k b 315 k c 420 k d 440 k

D Expansion in spring with spring constant K is 50 of compression in spring with spring constant K A1 kg block B rests as shown on a frictionless bracket A of same mass Constant force F 2N starts to act at time t 0 when the distance of block B from the end of bracket is 4m Find time in sec wher block B falls off the bracket R A 4m B

1 b 0 6 A a 0 8 A A wire of length 100 cm is connected to a cell of emf 2 V and negligible internal resistance The resistance of the wire is 302 The additional resistance required to produce a potential drop of 1 milli volt per cm is a 60 2 b 47 S e 572 d 35 Q 79 3x10 10 bea mu LO uniform wires A and B are of same metal and masses The radius of wire A is twice cistance of A and B when

In which case van t Hoff factor i remains unchanged 8 a PtCl reacts with aq KCl 4 b aq ZnCl reacts with aq NH c aq FeCl reacts with aq K Fe CN d KMnO reduced to MnO in alkaline medium 4

A silicon p n junction having No 5 x 10 6 cm 7 10 0 cm c 11 7 has a critical electrical field for breakdown is equal to 5 7 x 105 V cm The breakdown voltage for silicon p n is 21 V 20 V 24 V 22 V

60 If three charges q q and q are placed at the corners of an equilateral triangle of side L with q at the vertex what is the vector sum of forces acting on three charges 1 3 q L O 2 q 2 4 E L q

Taking acceleration due to gravity at th e earth surface to g 9 8m s2 and G 6 67 x10 11 S I Unit then calculate the average density of plant mars Given th at s its diameter 6780k m and the acce leration due to it s gravity 0 38 g ans 3 93 10 3 kg m 3

Two organ pipes a pipe of fundamental frequency 440 Hz closed at one end and a pipe of fundamental frequency 660 Hz open at both ends produce overtones Which choice below correctly describes overtones present in both pipes A After the first overtone of each pipe every second overtone of the first pipe matches every third overtone of the second pipe B After the first overtone of each pipe every third overtone of the first pipe matches every second overtone of the second pipe C After the first overtone of each pipe every second overtone of the first pipe matches every fourth overtone of the second pipe D After the first overtone of each pipe every third overtone of the first pipe matches every fourth

A huge rectangular compartment falls vertically down with acceleration a A gun fired at corner P requires to hit Q The bullet fired will hit Q if Question Type Single Correct Type 1 2 3 a g a g a g P

A swimmer who can swim in a river with speed av with respect to still water where v is the velocity of river current Jumps into the river from one bank to cross the river A If a 1 he cannot cross the river B If a 1 he cannot reach a point on other bank directly opposite to his starting point C If a 1 he can reach a point on other bank directly opposite to his starting point D He can reach the other bank at some point for anynon zero value of a

24 An electric dipole when placed in a uniform electric field E will have minimum potential energy when the angle made by dipole moment with field E is 1 T 2 3T 2 4 T 1 If frc of eq of 1

Comprehension For Q Nos 14 to 16 A container contains water up to a height of 20 cm and there is a point source at the centre of the bottom 4 of the container The celling of the room is 2 0 m above the water surface Refractive index of water ring of radius R floats on water surface such that its centre lies vertically above the source Ceiling 20 cm S 14 If radius of the ring is 15 cm the radius of the shadow of ring formed on the ceiling is 1 2 81 m 3 1 16 m V 22 7 cm 3 20 cm 2 1 65 m 4 4 46 m 15 The minimum radius of ring for which its shadow cannot be formed on the ceiling is nearly 2 21 5 cm 4 25 cm 16 Keeping the radius of ring 15 cm the level of water in the liquid is varied When the level of liquid becomes h the shadow of the ring disappears The value of his 1 5 2 cm V 5 7 cm 2017 A cm

of 28 A ray of light travelling along the line 3y other side of the x axis by turning 6 awayDivisi is incident on the x axis and after refraction it enters the ray travels is 1 x 3y 5 3 0 3 3x y 5 3 0 the x axis The equation of the line along which the refracted 2 x 3y 5 3 0 4 3x y 5 3 0

The queen is put at the center of a perfectly smooth carom board square with side 1 The striker strikes the queen with a speed Vo as shown in the figure Radius of the queen is 10cm and that of the striker is 2 10cm Coefficient of restitution for the collision between the queen and the striker is and that for the collision between the queen and the walls of the board is 1 Assume 1 radius of queen 190 2 A The value of d for which the queen gets in the hole A is 3 cm B The value of d for which the queen gets in the hole A is 2 cm C The value of d depends on the coefficient of restitution between the queen and the striker RL The value of d is independent of the coefficient of restitution between the queen and the striker

1 When two identical cells are connected either in series or in parallel across 2 ohm resistor they send the same current through it The internal resistance of each cell is 1 2 ohm2 1 2 ohm 3 12 ohm 4 21 ohm

A rod mas m length is placed vertically on smooth horizontal surface Rod in released and after some time velocity of COM of rod become V and at this moment rod makes 60 with horizontal Find angular momentum of rod about ICOR 1 3 m Vo 12 12m V 7 2 4 60 mlV 7 7m Vo 12

A telescope has an objective lens of focal length 3 200 cm and an eye piece with focal length 2cm If this telescope is used to see a 50 meter tall building at a distance of 2km what is the height of the image of the building formed by the objective lens 1 5 cm 3 1 cm 2 10 cm 4 2 cm vada afuges d200 cm 3 2cm 2 km 50 m ft man 1 5 cm 3 1 cm fafen fugen du go agafar 2 10 cm 4 2 cm

The length breadth and height of a given rec tangle box 150 cm and 20 CM respectively t his box is kept on the ground in three differe nt ways one by one which of the following s tatement is correct about the pressure exert ed by the box on the ground

4 A magnetic needle lying parallel to a magnetic field requires X units of work to turn it through 60 The torque necessary to maintain the needle in this position is 1 2X 3 3 2 X 2 X 4 3x

21 Assertion The velocity of a body at the bottom of an inclined plane of given height is more when it slides down the plane compared to when it rolls down the same plane Reason In rolling down a body acquires both kinetic energy of translation and kinetic energy of rotation

Rank in order from highest to lowest the liquid heights ha to hd The air flow is from left to right The liquid columns are not drawn to scale O ha hp hd hc ho hg hc h Ohg hc hb ha O the shazhe h h Direction of airflow h suction pump

A cylinder of radius 4cm and height 10cm is immersed in two liquids as shown Specific gravity of oil is 0 5 2cm of cylinder is in the air Select the incorrect statement Neglect atmospheric pressure O Force exerted by oil on the cylinder is zero O Force exerted by water on the cylinder is 0 96 newton O Force exerted by both water and oil is 1 14 TT newton Oil Wat 4cm Frequency of oscillation does not depend on density of oil if cylinder is displaced slightly 4

List I A Total Internal Reflection 3 Dispersion and Total Internal reflection C Scattering D Semiconductor List II 1 Zener diode II Blue color of sk III Mirage IV Rainbow

Can continuity equation be used in inlet and outlet of rotameter inlet point B outlet point A is mass flow rate conserved in rotameter fluid flow Rotameter Can continuity equation be used in inlet and outlet of rotameter inlet point B outlet point A

A body is projected upwards at an angle 30 to the horizontal and the range is R Another body is projected upwards at an angle 60 with the horizontal and the range is R If both the bodies have the same initial velocity then

4 1 pt In the EMG exercise a subject s maximal p p measurement was 6 85 mV while their tonus measurement in the same forearm was 0 062 mV Set up the calculation to determine what percent of the maximal value the tonus EMG was

6 A block of wood is kept on a horizontal table The mass of the wooden block is 6 kg and its dimensions are 10 cm x 10 cm x 10 cm What is the pressure exerted by the wooden block on the table A 1100 pa B 2200 pa C 8850 pa D 5880 Pa 1

39 An equilateral trignale of side length is formed from a piece of wire of uniform resistance The current I is fed as shown in the figure Then the magnitude of the magnetic field at the centre O is b 1 2 3 2 l 3 3 3 2 l Mol 2 l 4 zero a

9 A player whose height is 2 0 m runs towards east with a speed of 20 km h How much potential difference will be induced between his head and feet Horizontal component of earth s magnetic field BH 4 0 x 10 5 Wb m If he runs towards north 2 then

55 A flow of 105 electron per second in a conducting wire constitutes a current of 4 1 6 x 10 0 A 1 1 6 x 10 24 A 2 1 6 1024 A 3 1 6 x 10 14 A 4

The electrostatic energy of Z protons uniformly distributed throughout a spherical nucleus of radius R is given by E 3 Z Z 1 e 5 4 R The measured masses of the neutron H N and O are 1 008665 u 1 007825 u 15 000109 u and 15 003065u respectively Given that the radii of both the N and O nuclei are same 1 u 931 5 MeV c c is the speed of light and e 4 0 1 44 MeV fim Assuming that the difference between the binding energies of N and O is purely due to the electrostatic energy the radius of either of the nuclei is

Three liquids of densities P P2 and P with P P2 P3 having the same value of surface tension T rise to the same height in three identical capillaries The angles of contact 0 0 and 0 obey 1 0 0 0 2 2 0 0 0 3 0 0 0 20 4 0 8 0 0 10 AT A PPP fax 0 0 0 affafera 1 0 8 0 2 x 0 0 0 3 0 8 0 20 4 0 0 0 0

Q6 of 54 A hollow cylinder of radius 4R is rotating about fixed horizontal axis passing through point O with angular velocity A solid cylinder of radius R is rolling without slipping with respect to inner surface of hollow cylinder At the given instant the line OC has angular velocity of 2000 Point A and B are topmost and bottom most points of solid cylinder respectively and C is its centre Then at the given instant

6 What is the value of linear velocity if 3i 4j k and 7 51 6j 6k a 6 2j 3k c 4 13j 6k CBSE PMT 1999 CPMT 1999 2001 Pb PMT 2000 Pb CET 2000 b 6i 2j 8k d 18i 13j 2k

5 The maximum and minimum magnitude of the resultant of two given vectors are 17 units and 7 unit respectively If these two vectors are at right angles to each other the magnitude of their resultant is Kerala Engg 2000 a 14 c 18 16 13

A body of weight 50 N is placed on a horizontal surface A force of 28 2 N is applied on it as shown in diagram The frictional force and normal reaction on the body are 1 2N 3N 3 10N 15N p 0 8 28 2N 2 5N 6N 4 20N 30N

A coil of radius 1 cm and of turns 100 is placed in 9 the middle of a long solenoid of radius 5 cm and having 5 turns em parallel to the axis of solenoid The mutual inductance in millihenry will be 1 0 0316 2 0 063 3 0 105 4 Zero f 1 cm 100 eft 5 t cm tuftafer 5 cm i 1 0 0316 3 0 105 2 0 063 4

A conducting wire of length l metre carries T 13 ampere current along positive x direction It is placed in uniform magnetic field B B i j k T then magnitude of magnetic force exerts on wire is 1 2 B It 2 Zero BIL 4 BIC tha an I Valle x feen sfee are 45 B Bo i j k zuren afera att de 1 2B J B It 3 2 4 BIE

When force F is applied to the combination of two springs shown in the figure the elongation in upper spring will be the whole system is inside a lift which is moving upwards with an acceleration The upper spring is ideal while the lower spring has mass M TE A B C D M g a K K F M g a K K K K F M g a K K F M g a

67 From a circular disc of radius R a square is cut out with a radius as its diagonal The centre of mass of remaining portion is at a distance from the centre R R 4 2 2 2 a b R 2 c R 2 d

A solid sphere a hollow sphere and a ring are released from top of an inclined plane frictionless so that they slide down the plane The maximum acceleration down the plane is for no rolling Question Type Single Correct Type 1 solid sphere 2 hollow sphere 3 ring

A screw gauge has 100 divisions on circular scale and pitch is 0 5 mm When we fix a wire between it s jaws it reads 2 divisions on main scale and 48 divisions on circular scale If the screw gauge has no zero error radius of wire is A 2 48 mm C 0 62 mm B 1 24 mm D 0 31 mm

Two bodies A of mass 1 kg and B of mass 3 kg are dropped from heights of 16 m and 25 m respectively The ratio of the time taken by them to reach the ground is 1 3 4 5 12 5 2 4 5 4 5 12

An ideal voltmeter V and ideal ammeter A are connected in a circuit as shown in the figure If the reading of the voltmeter is 32 V the reading of ammeter will be 4 A 8 A O 10 A 80 A AMAISIA WIRLE 892

Dimerisation of NO is an exothermic reaction If enthalpy of reaction is AH then the minimum value of activation energy for forward reaction E will be O Equal to AH Equal to zero O Greater than AH Greater than threshold energy