Basic Physics Questions and Answers

A mixture of 250 g of water and 200 g of ice at 0 C is kept in a calorimeter of water equivalent 50g If 200g of steam at 100 C is passed through the mixture then the final amount of water in the mixture will be Latent Heat of ice 80 cal g Latent Heat of vaporisation of water 540 cal g and specific heat of water 1 cal g C 1 1 A B C 450 g 622 g 572 g

A pulse of light of duration 100 ns is absorbed completely by a small object initially at rest Power of the pulse is 30mW and the speed of light is 3 x 10 m s The final momentum of the object is A 0 3 x 10 7kgms B 1 0 x 10 kgms C 3 0 10 7kgms D 9 0 10 7kgms 1

A particle moves from point 5 9 7 to 8 5 2 with constant speed 10 2 m s on a straight line A force F 31 41 N is acting on particle throughout its journey Choose the correct statement s Velocity vector of the particle is 61 81 10k m s Work done by the given force in the journey is 7 J Power delivered by the given force at any time is 14 W There must be some other force acting on the particle

Four point charges each of q are rigidly fixed at the four corners of a square planar soap film of side a The surface tension of the soap film is y The system of charges and planar film are in 1 N equilibrium and a k 2 where k is a constant Then N is

On a 100 km track a car travels the first 50 km with a uniform speed of 40 km hr How fast must the car travel the next 50 km so as to average 60 km hr for the entire trip Answer should be in km hr

A string with one end fixed on a rigid wall passing over a fixed frictionless pulley at a distance of 4m from the wall has a point mass M 2 kg attached to it at a distance of 3m from the wall A mass m 0 5 kg attached at the free end is held at rest so that the string is horizontal between the wall and the pulley and vertical beyond the pulley What will be the speed in m sec with which the mass M will hit the wall when mass m is released 3 m 4 m M m

A body is suspended by a string connected on ceiling of a lift When lift accelerates then tension in string found to be doubled then acceleration will be 1 4 9 m s 2 9 8 m s 3 19 6 m s 4 2 45 m s

An archer shoots an arrow at a 75 m distant target the bull s eye of the target is at same height as the release height of the arrow If d 75 m and v 37 m s At what angle must the arrow be released to hit the bull s eye if its initial speed is 37m s

Oscillations A The phase difference between the two particles shown below is n Assuming both particles have same time periods and same amplitudes mean position R If the particles cross each other while they

a new system of units mass acceleration and frequency are taken as fundamental units If unit of mass is 10g unit of acceleration is m s and unit of frequency is 2 sec in a new system of units find the value of 1 J in this system

For question numbers 13 and 14 two statements are given one labelled Assertion A and the other labelled Reason R Select the correct answer to these questions from the codes a b c and d as given below a Both A and R are true and R is correct explanation of the assertion b Both A and R are true but R is not the correct explend of the assertion A is true but R is false d A is false but R is true 13 Assertion kWh is a commercial unit used for expressing consumed electric energy Reason Kilowatt hour is the unit of electric power 14 Assertion The 200 W bulbs glows with more brightness than 100 W bulbs Reason A 100 watt bulb has more resistanc than a 200 W bulb

Board Competitive Exams 14 If the fundamental frequency of string is 220 cps the frequency of fifth harmonic will be 1 44 cps 2 55 cps 3 1100 cps 4 440 cps Waves

19 A locomotive approaching a crossing at a speed of 20 ms sounds a whistle of frequency 640 Hz when 1 km from the crossing There is no wind and the speed of sound in air is 330 ms What frequency is heard by an observer 3 km on the straight road from the crossing at right angle 1 600 Hz 3 660 Hz Sound Observer 3 km 20 ma Crossing Motion of Locomotive 2 630 Hz 4 720 Hz

Which of the following statements is false the mass of two bodies will be same if they exhibit same inertia the weight of a body at the centre of the earth is zero if a ball is thrown vertically upwards by a man sitting in a uniformly moving car then the ball will behind the man the mass of a body remains constant at all places

A force of 10 N gives a mass m an acceleration of 2 ms 2 and a mass m2 an acceleration of 3 ms 2 What acceleration would it give in m s2 if both the masses were tied together Options 1 2 1 6 2 4 2 8

Zero Marks 0 In all other cases pulley one meter in diameter rotating at 600 revolutions a minute is brought to rest in 20 s by a constant force of friction on its shaf How many revolutions does it make before coming rest

R If the particles cross each other while they move in the opposite direction they have a phase difference of x radian A All trigonometric functions are periodic R All trigonometric functions can represent SHM

2 If wavelength of a photon is 6 6 A then the mass of the photon is h 6 6 x 10 34 Js 1 6 1 x 10 2 kg 2 3 3 10 33 kg 3 5 4 x 10 34 kg 4 2 5 x 10 20 kg

In Young s double slit experiment both the slits produce equal intensities on a screen A 100 transparent thin film of refractive index u 1 5 is kept in front of one of the slits due to which the intensity at the point O on the screen becomes 75 of its initial value If the wavelength of monochromatic light is 720 nm then what is the minimum thickness in nm of the film Vacuum 0

oscillations shorter length has completed 1 2 2 1 3 5 4 3 33 Two masses M and Ma are hung from two strings of length and a respectively They are executing SHM with frequency relation f 2f then relation 1 A does not depend on mass 4 2 A 41 does not depend on mass 3 A 21 and M 2MB 4 A and MA

A ball moving with a velocity 20 m sec has a mass of 50 gm If collides against a wall normally and is rebounded normally with the same speed If the time of impact of the ball and the wall is 40 milli seconds the average force exerted on the wall in dynes is 2 1 25 x 107 4 5 x 106 1 zero 3 2 5 107

A body of mass m is thrown vertically upwards with a velocity v It reaches to a height h and returns after t seconds Then the total change in its momentum is 1 zero 3 mgt 2 mv 4 mght

39 At what height from the surface of earth the gravitation potential and the value of g are 5 4 x 10 J kg 6 0 ms respectively Take the radius of earth as 6400 km 1 2600 km 2 1600 km 4 2000 km 3 1400 km

A block of mais in is tied to a spring NIP L and other end of spying k is fixed at point o 4f black mover moves in horizontal circular path on a smooth horizontal surface with con t angular find spring farce velocity W

between by al is ontal of force 51 Two beads A and B move along a semicircular wire frame as shown in figure The beads are connected by an inelastic string which always remains tight At an instant the speed of A is u ZBAC 45 and ZBOC 75 where O is the centre of the semicircular arc The speed of bead B at that instant is a 2u u c b u 2 d u B O centre Lu

A man can just push a box on 37 slope When he keeps it at the point where the angle increases to 53 he can just hold it from sliding back If the coefficient of friction between 1 the box and the slope is u find Assume that the man is applying same magnitude of force along the tangent to the curve only a 1 53 a Live 37 b 3 7

Two balls A and B are both thrown with horiz ntal initial velocities of 6m s and 8m s from the edge of a vertical cliff Their initial velocities are perpendicular and they hit the ground a X and Y The height of the cliff is 980 meters Find the distance XY

Two ships are resting on sea surface at distances a b from a fixed point O respectively They start moving towards the point O with constant velocities V and v respectively If the ships subtend an angle 0 at O find the shortest distance of their separation 0 2

5 A satellite is launched into a circular orbit of radius R around the earth A second satellite is launched into an orbit of radius 1 01 R The period of the second satellite is larger than that of the first one by approximately 1 0 5 2 1 0 3 1 5 4 3 0

Parallel rays of light are refracted by a convex lens to a point called the distance of the The location and nature of the image depends upon the from the lens Any lens forms an image by a where the light rays bend because the changes when it enters into another medium phenomena called

3 35 shows a 2 0 V potentiometer used for the determination Figure of internal resistance of a 1 5 V cell The balance point of the cell in circuit is 76 3 cm When a resistor of 9 5 Q is used in the external circuit of the cell the balance point shifts to 64 8 cm length of the potentiometer wire Determine the internal resistance of the cell open A 1 5 V 9 5 2 www 2 0 V B

24 A small iron ball of mass m is suspended with the help of a massless rod of length L and is free to oscillate in vertical plane Its time period of oscillation is 1 2 3 2 mL 2g 9 2 2 4 2 mL g m gL

A thin horizontal circular disc is rotating about a vertical axis passing through its centre An insect is at rest at a point near the rim of the disc The insect now moves along a diameter of the disc to reach its other end During the journey of the insect the angular speed of the disc a continuously decreases b continuously increases c first increases and then decreases d remains unchanged

The transverse displacement wave on a string y x t e ax b 2 ab xt is y x t of a given by This represents a a wave moving in x direction with speed b standing wave of frequency b 1 c standing wave of frequency 6 d wave moving in x direction with speed a

Two uncharged capacitors of capacitance 2 F and 4 F connected by a battery as given in the figure The work done by the battery in charging will be 1 216 J 2 10 4 F HE 2 F 6 V 2 108 J

19 A particle is executing SHM with total mechanica energy 90 J and amplitude 6 cm If its energy in somehow decreased to 40 J then its amplitude wi become 1 2 cm 3 2 4 cm 4 c cm

In tan A and tan B positions of a magnet the magnetic field at a distance are represented by B and B respectively then A B Ho 2 Md 4n d 1 B B B d l C R 2 Boid l B M Ho 4 d 1 3 2 D both A and C

21 A 2 kg object oscillates on a spring of forc constant k 400 N m The damping constar has a value of b 2 00 kg s The system is drive by a sinusoidal force of maximum value 10 and angular frequency o 10 rad s What the amplitude of the oscillations 1 1 404 m 3 0 01 m 2 0 05 m 4 202 m

Velocity of a body is given as a function of time as V 15 2t The body is undergoing B Uniform motion D Uniform acceleration A Uniform retardation C Non uniform acceleration

B If the particle repeats its motion after a fixed time interval of 8 s then after how much time its maximum value of PE will be attained after attaining its minimum value 1 2 s 2 4 s 3 8 s 4 1 s 9 A particle is executing SHM with total mechanical

Iwo small conductors X and Y are given charges q and q respectively Now they are placed inside a hollow metallic conductor Z carrying a charge Q If all the three conductors X Y and Z are connected by conducting wires as shown the charges on X Y and Z will be respectively A 91 92 91 92 2 1 92 Q 2 1 9 92 Q 9 92 Q 0 91 B Q 91 93 Q 9 92 Q 9 92 3 3 3 0 D 0 0 Q 9 9 X 9 Jawyz Y qz

1 North 2 South 3 East An electron is moving along x direction To get it moving along an anticlockwise circular path in x y plane magnetic field applied along 1 y direction 2 direction 3 y direction 4 z direction 8 A magnetic field is applied at perpendicular to the axis of cylinderical Cathode reys Positive age Amado

2 3a What do you mean by UCST and LCST in respect to liquid liquid equilibrium raw the phase diagram of the system having both UCST and LCST conditions 3b What is condensed phase rule Draw and explain the phase diagram of sulfur ystem At 100 C the specific volume of water and steam are respectively 1 c c and

26 A block of mass m is initially moving to the right on a horizontal frictionless surface at a speed v It then compresses a spring of spring constant k At the instant when the kinetic energy of the block is equal to the potential energy of the spring the spring is compressed a distance of A v m 2k B 12a m k C C

1 Tick the correct sentences a We must eat dirty food b Vegetables are good for us c Too many sweets are bad for our health d Doctors help us take care of our body e It is not good to eat junk food C

26 The instant at which a bulb is switched on its power is maximum then it decreases to a steady value Explain For driving current of A for 6 minute in a circuit 1000 J of work is to be done The emf of

40 An automobile negotiates a turn of radius m on a road which is banked at the curve at angle 30 to the horizontal If 3 1 coefficient of friction between road surface and automobile is then maximum speed at which the car can negotiate the tur 3 without skidding will be g 10 m s 10 ms 1 10 3 ms 1 20 3 ms 1

22e A signal has been reported to occur at 600 Hz downfield from TMS in an NMR pectrometer with a 300 MHz operating frequency What is the chemical shift of the ignal 1 23a What do you mean by UCST and LCST in respect to liquid liquid equilibrium brow the phoco diagram of the custom having both UGST and ICST conditions

Unpolarised light of intensity 32 W m2 passes through three polarizers such that the transmission axis of the last polarizer is crossed with that of the first The intensity of final emerging light is 3 W m 2 The intensity of light transmitted by first polarizer will be a 32 W m 2 c 8 Wm 2 1 2 3 CORRECT b 16 W m 2 d 4Wm 2

A small body starts falling onto the Sun from a distance equal to the radius of the Earth s orbit The initia velocity of the body is equal to zero in the heliocentric reference frame Making use of Kepler s laws find how long the body will be falling