Physics Questions

An elevator initially at rest supported by a cabl passes over a pulley of radius 0 4 m It is accelerater upwards with 0 6 m s Find number of rotation made by pulley during 10s 1 23 88 3 5 97 2 11 94 4 8 96

6 Extreme position to half of the amplitude A particle undergoes simple harmonic motion having time period T Find the time taken to complete 318 oscillation TC The displacement of a particle executing simple harmonic motion is given by y 10sin 6t 3 Here

5 The temperature of inversion of a thermocouple is 620 C and the neutral temperature is 300 C What is the temperature of cold junction AIPMT Prelims 2005 1 20 C 2 320 C Pano 3 20 C 4 40 C

a 0 5 Am A substance cools from 75 C to 70 C in T minute from 70 C to 65 C in T minute and f 65 C to 60 C in T3 minute then a T T T c T T T3 b T T T d T T T pro at temperatures 20 C and 40 C When same mass of both of them is mixed of their specific beats

c 75 C d 0 C 9 A wall has two layers A and B each made of different materials The layer A is 10 cm thick an Bis 20 cm thick The thermal conductivity of A is thrice that of B Under thermal equilibriun temperature difference across the wall is 35 C The difference of temperature across the laye A is aguibu b 14 C a 30 C d 5 C c 8 75 C A wall has two lafiora ond Roach made of different C

Example 1 3 How much positive and negative charge is there in a cup of water

Figure shows the kinetic energy K of a simple pendulum versus its angle 0 from the vertical The pendulum bob has mass 0 2 kg If the length of the pendulum is equal to g meter then find n g 10 m s 100 K MJ 15 10 5 100 0 mrad

28 A solid sphere of mass m and radius R is rotating about its diameter A solid cylinder of the same mass and same radius is also rotating about its geometrical axis with an angular speed twice that of the sphere The ratio of their kinetic energies of rotation Esphere Ecylinder will be 1 1 4 3 2 3 2 3 1 4 1 5

The equivalent resistance between point A and B is RAR R BR a R b R 4 c 4R d 2R 3

ap a 0 ap ap 2 9 27 a physics Laws of Motion 9 279 T 6a T AT 129 130 g my OR from 40 a NE 72 x2 1kg 19 NEET T 6xQ 6x9 13 physics Laws of Motion Type SP for 9 10m 1 a 16 imion M ap Force 1 1 Ma mig T m a mig ma 1 physics Laws of Motion T 7 m m g mitm a Alo T 1 Ma M 160 m m m 9 6x10 NEE UDA T mg ma m a m y 1 Shortcut a T M 60 T NEET Mnet 2m Mg UDAAN UDAAN T 7 mg ma m a m g T 7 mgm 9 m c Mzg Ti T m m g m m NEET NEET UDAAN mig mg m m M

a Example 1 13 An early model for an atom considered it to have positively charged point nucleus of charge Ze surrounded by a uniform density of negative charge up to a radius R The atom as a whole is neutral For this model what is the electric field at a distance r from the nucleus R P

59 In a projectile motion the velocity 1 is always perpendicular to the acceleration 2 is never perpendicular to the acceleration 3 is perpendicular to the acceleration for one instant only 4 is perpendicular to the acceleration for two instants

60 7 As shown in figure light P enters to slab at an angle 60 with normal and inside slab Q makes total internal reflection Find minimum refractive index of slab 1 1 72 3 1 32 2 1 52 4 1 12

A small coin is resting of filled with a liquid A ray of light from the coin travels upto the surface of the liquid and moves along its surface see figure 22 4 cm 3 cm a g g pia R Maz Coin How fast is the light travelling in the liquid 1 1 2 x 108 m s 2 1 8 x 108 m s 3 2 4 x 108 m s 4 3 0 x 108 m s wh PS 11 N

A uniform rod AB of length and mass m is free to rotate about A The rod is released from rest in the horizontal position Given that the moment of inertia of the rod about A is me acceleration of the rod will be 3 1 3g 20 3 mg A l B 2 the initial angular AIPMT 2007 2g 3l 3 4 gl

Four ideal cells each of emf 10 V are connected as shown in figure The current through 2 Q2 resistor is 1 2 A 2 4 A 3 1 A 10V 10V www 2Q2 89 10V 10V

Two tuning forks A and B produce 4 beats per second The fork A is in resonance with a 30cm length of sonometer wire and B is in unison with 25cm of the same wire at same tension The frequency of the forks A and B respectively is a 20Hz 24 Hz b 24 Hz 20 Hz c 25 Hz 20 Hz d none

Two ends of a plank are placed on two wedges The plank gets depressed by 1 mm when a load of 2 kg is hung from its mid point What will be the depression of the plank if 2 5 mm a load of 5 kg is hung from its mid point

1 20 Mark for Review The effect of eddy current loss in transformer is reduced by O Using laminated core Using thick wire for winding Using solid non laminated core 18 59 min se Using thin wire for winding

The activation energy of a reaction can be determined from the slope of which of the following graph k vs T k vs 2 T

118 Four metallic plates each with a surface area of one side A are placed at a distance d from each other The plates are connected as shown in the circuit diagram Then the capacitance of the system between a and b is 38 A a b c d 280 A 3d d 2804 d 380 A 2d min s

An automobile moves on a road with a spee 54 km h The radius of its wheels is 0 45 m the moment of inertia of the wheel about its of rotation is 3 kg m If the vehicle is broug rest in 15s the magnitude of average fo transmitted by its brakes to wheel is 1 2 86 kg m s 2 6 66 kg m 3 8 58 kg m s 4 10 86 kq m

ample 4 Two forces are such that the sum of their magnitudes is 18 N and their resultant is perpendicular to the smaller force and magnitude of resultant is 12 Then the mag nitudes of the forces are A 12 N 6N C 10 N 8 N B 13 N 5N D 16 N 2N 0

3 A small hole of radius r is made in a container filled with liquid of density p as shown in the figure kept in atmosphere at pressure P A thin capillary of length I is attached to the hole the viscosity of the liquid is n Initially the capillary is closed using a cork to avoid flow of liquid which is then removed to start the flow find a Frictional force between capillary and the cork to stop liquid from coming out b Speed of efflux just after cork is removed c Horizontal range of the liquid H 2 2 pngHr PgHr 2 16nl 16nl PgHr pr pngHr gH H 2 b pngHr pgr 4 pngHr pr gH pr 16nl 16ml pgHr

Three long straight parallel wires carrying current arranged as shown in figure The force experienced by 25 cm length of wire C is C A C 10 3 N zero 30 A dra 3 cm 10 A B D 2 cm 20 A 2 5 x 10 3 N 1 5 10 N

11 Choose the correct option 1 1 AU 9 46 x 1015 m 2 1 A 10 8 cm 3 1 ly 3 26 Parsec 4 1 Parsec 1 496 10 1 m 12 The weakest fundamental force is 1 Strong nuclear force 2 Weak nuclear force 3 Electromagnetic force 4 Gravitational force 13 The parallax of a far off star as measured from two diametric extremes on the equator of the earth is 1 minute of arc If radius of earth is 6400 km then the distance of the star from the earth is 1 44 x 106 km 3 11 x 106 km 2 22 x 106 km 4 33 x 106 km 14 If the dimensions of a physical quantity are given by Ma Lb Tc then the physical quantity will be 1 Work if a 1 b 1 c 2 2 Time if a 0 b 1 c 1 3 Surface tension if a 1 b 0 c 2 4 Velocity if a 0 b 1 c 1 15 If force F velocity V and time 7 are taken as fundamental quantities the dimensional formula for energy will be 1 F V T 3 F VT 16 Zero error in an instrument introduces 1 Random error 2 Personal error 3 Least count error 4 Systematic error 17 If a number 4 732615 is to be 2 FVT 4 F V T 1 4 732 3 4 733 unded off up to three significant figures then the new number will be 20 If the units of mass length and time each are doubled then the unit of velocity will be 2 4 73 4 4 7 18 Which of the following is not the unit of time 1 Shake 2 Barn 4 Second 3 Year 19 The diameter of a cup is measured using a vernier caliper The 20 vernier scale divisions are equal to 18 main scale divisions If one division of main scale is x mm then least count of the instrument is x 21 The least count of a stopwatch is 0 2 s the time of 100 oscillations is found to be 200 s percentage error in the The maximum measurement of time is 1 10 3 0 2 22 1 Doubled 2 Halved 3 Tripled 4 Remains same For a systematic error which of the following graph is correct 2 24 Error Raka Error Error Error dical I JEF No of observations 23 An object travels 20 m in 4 s and then another 20 m in next 10 s then choose the correct option 7 2 0 1 4 5 No of observations m s No of observations 1 Average velocity for entire journey must be 20 No of observations m s 2 Average speed for entire journey must be 20 7 15 3 Average velocity for entire journey must be zero 4 Average speed for entire journey must be zero The distance travelled by an object star from rest and moving with an accel m s in the 3rd second is 15

3 Open end mercury manometer is connected to a gas chamber containing gas at a pressure of 1 38 bar The barometric pressure is 750 mm Hg Mercury level in the arm connected to gas chamber stands at 11 3 cm What is the reading in open arm of the manometer

A particle A of mass m and charge Q moves directly towards a fixed particle B which has charge Q The speed of A is a V when it is far away from B The minimum separation between the particles is not proportional to

If in a p n junction a square input signal of IU V is applied as shown At 5 V A then the output across RL will be 5 V 5 V T 10 V RE

XY as sh the path of electron What will be the direction of current if any induced in the coil Please explain what when start movin ll happen ectron afters crossing with diagram a abcd a d O C b adcb c The current will reverse its direction as the electron goes past the coil

er circuit is set up as shown The potential gradient across the potentiometer wire is k volt cm and the ammeter present in the circuit reads 1 0 A when two way key is switched off The balance points when the key between the terminals i 1 and 2 ii 1 and 3 is plugged in are found to be at lengths cm and cm respectively The magnitudes of the resistors R and X in ohms are then equal respectively to 1 W LO A 1 ke and kl R 3 X B G 2 k l and kl

Explain the phenomenon of beats An ambulance blowing a siren of frequency 700 Hz is travelling towards a vertical reflecting wall with a speed 7 2 km h 1 Calculate the number of beats heard in one second by the driver of the ambulance Take speed of sound as 340 ms

The basic reason of the force of surface tension is the tendency of the surface of a liquid to a Contract c maintain its area expand or contract 1 Point Option a Option b Option C Option d b expand d either to

If there is a very small air bubble inside a glass sphere u 1 5 of radius 10 cm at distance 4 cm below its surface then its apparent depth when viewed normally from outside will be approximately Only one correct answer A 2 cm B 2 4 cm C 3 1 cm D 3 6 cm

19 Two particles executing SHM of same frequency meet at x A 2 while moving in opposite directions Phase difference between the particles is It 1 3 51 2 4 2 3

In a refrigerator the system extracts heat of 600 J from a cold reservoir and released 900 J of heat to hot reservoir The coefficient of performance of a refrigerator is given by NCERT Pg 314 1 2 3 6 2 3 4 9

When a magnet is being moved towards a coil the induced emf does not depend upon 1 the number of turns of the coil 2 the motion of the magnet 3 the magnetic moment of the magnet the resistance of the coil

The absolute temperature of air in a region linearly increases from T and T in a spac of width d Find the time taken by sound wave to goes through the region in terms of T T d the speed of sound at 273 K is V A NARAYGROUP T 273 T D 2 4 7 273 T

A car s displacement from home is measured in miles by the the function d t t 2 t 12 where t is measured in minutes Which option represents all times that the car is at least 21 miles from home a At 2 minutes and 12 minutes b Between 2 and 12 minutes c Less than 2 minutes d After 13 8 minutes e Answer is not there

The circuit below represents a non inverting integrator For high frequencies o the input impedance is a 0 b R For low frequencies o the input impedance is c R 1 ORC d a V 1 RC V di b The voltages at the inverting and non inverting terminals of the op amp are nearly c The voltage at the non inverting terminal of the op amp and the current in the resistor attache are 2 out of phase 2 d The current in the two resistors are in phase

A block of mass 1 kg is placed on a fixed wedge at a height of 2 m as shown in figure Find maximum compression in the spring of spring constant k 50 N when the block is set free from the position 2 m 1 kg 0 2 37 2m k www 0 5

27 3 2n s 4 3 s A particle of mass 10 g is undergoing SHM of amplitude 10 cm and period 0 1 s The maximum value of force on particle is about 1 5 6 N 2 2 75 N 3 3 5 N

a A 15 kg brick is moves along an x axis Its acceleration as a function of its position is shown in figure The scale of the figure s vertical axis is set by a 24m s What is the net work performed on the brick by the force causing the acceleration eration as the brick moves from x 0 to x 8 0 m a m s 4 x m b Figure gives spring force F versus position x for the spring block arrangement of figure The scale is set by F 160 0N We release the block at x 12 cm How much work does the spring do on the block when the block moves from x 8 0cm to a x 5 0 cm b x 5 0 cm c x 8 0 cm and d x 10 0 cm 2 Fx F 1 0 3 6 8 1 x c 2 10

A chain is held on a frictionless table wi th 1 5th of its lengt h hanging over the edge If the chain h as a length L and m ass M how much w ork is required to sl owly pull the hangin g part back on the t

When a battery is connected across a series combination of inductance L and resistance R the variation in current with time tis best represented by Only one correct answer B K h 2

30 The zeroth law of thermodynamics for three systems J K CET 2013 A B and C in contact demands that a A and B are in thermal equilibrium b B and Care in thermal equilibrium c A and Care in thermal equilibrium d A B and C are in thermal equilibrium

Velocity v versus time t graph of a particle moving in tan o tan then average speed of the particle till the time its velocity becomes zero is v m s a straight line is shown in the figure If 2 m s 1 B t s 2

A car 1000 kg is going 20 m s on a level road and slams on the brakes The skid marks are 25m long a What is the change in kinetic energy during the skid b What is the work done on the car by the road c What is the work done on the car by gravity

solid sphere placed on rough horizontal surface is given velocity vo as shown at t 0 If coefficient of riction is then time to at which it rolls without slipping is 20 Find n nug 0 0 Vo

23 For a particle executing simple harmonic motion the amplitude is A and time period is T The maximum speed will be 1 4AT 24 3 2 A 2A 2 24 4 2A T