Physics Questions

Two particles of equal masses have velocities V 21 m s The first particle has an acceleration a 31 31 2 while the acceleration of the other particle is zero The centre of mass of the particles moves in a A circle B parabola C straight line D ellipse

10 The poisson s ratio of a material is 0 4 If a force ia applied to a wire of this material there is a decrease of cross sectional area by 2 The percentage increase in its length is a 3 c 1 b 2 5 d 0 5

e 4 9 and A stone of mass 0 05 kg is thrown vertically upwards What is the direction and magnitude of net force on the stone KCET 2015 during its upward motion a 0 49 N vertically downwards b 9 8 N vertically downwards c 0 49 N vertically upwards d 0 98 N vertically downwards A ball A is thrown up vertically with a speed u and at the same instant another ball B is released from a height h At time t

2 b State the schematic plots for each of following cases of photoelectric effect i Photoelectric current vs potential difference for two different intensities of UV light ii Maximum photoelectron kinetic energy us frequency of incident UV light for two different metal surfaces having different work functions 4

6 A man moves on a horizontal road towards east at a speed of 1 km hr and the rain appears to him vertical at a speed of 2 km hr The actual speed of the rain in km hr is 1 1 3 3 2 2 4 5

The circuit is in steady state Now a zero resistance wire is joined between points A and B If the heat dissipated after joining the wire is nCV then find the value of n Round off to two decimal places A C www 2C

A particle accelerates from rest with acceleration 5m s After sometime particle moves with constant velocity Then it decelerates with 5 m s and finally comes to rest In whole of ourney it takes 25 sec and the average speed in the journey is 72 km hr Then A The time interval during which it has moved with constant velocity is 15 sec B The maximum velocity is acquired by it is 25 m s C The time interval during which it has moved with constant velocity is 25 sec D The maximum velocity is acquired by it is 30 m s

Une has to throw a particle from one side of a fixed sphere in diametrical plane to another side such that it jus grazes the sphere Minimum possible speed for this is 2gR a B Find a B

A constant force acts for 5 seconds on a body of mass 5 quintals and then cease to act During the next 5 s the body describes 100m Find the magnitude of th force a 1000N b 2000 N c 4000 N d 6000 N

7 Following figure shows four situations in which positive and negative charges moves horizontall through a region and gives the rate at which each charge moves Rank the situations according t the effective current through the region greatest first i 7C sec ii 3C sec 1 i ii iii iv 3 i ii iii iv 4C sec iii 2C sec iv 5C sec 2 i ii iii iv 4 i ii iii iv 6C sec 1C sec

2 27 On an X temperature scale water freezes at 125 X and boils at 375 X On a Y temperature scale water freezes at 70 Y and boils at 30 Y The value of temperature on X scale is on which value of temperature on y Scale becomes 50 Y

A uniform magnetic field of induction B is confined to a cyclindrical region of radius R The magnetic field is increasing at a constant rate of dB tesla second An dt electron e m placed at the point P on the periphery of the field experiences an acceleration X 1 X X X X X X X X x x R X X X P X X x x X X 1eR dB 2m dt towards left X Question Type Single Correct Type X X X

One has to throw a particle from one side of a fixed sphere in diametrical plane to another side such that it just grazes the sphere Minimum possible speed for this is 2gR x B Find a B Ground

The outstretched hands and arms of a figure skater preparing for a spin can be considered a slender rod pivoting about an axis through its center Ibar 12m 1 where is the length of the bar When the skater s hands and arms are brought in and wrapped around their body to execute the spin the hands and arms can be considered a thin walled hollow cylinder The hands and arms have a combined mass 7 kg When outstretched they span 1 5 m When wrapped they form a cylinder of radius 30 cm The moment of inertia about the rotation axis of the remainder of the body is constant and equal to 0 4 kg m If the original angular speed is 0 6 rev s what is the final angular speed W 1 00 rev s Determine how much the figure skater s rotational KE increased NOTE We express energy in J To get J you must convert your angular velocities to the appropriate mks units which are rad s AKE

1 A ring of radius R has charge Q distributed uniformly over it A charge q is placed at the center of the ring such that the electric field becomes zero at a point on the axis at distance R from the center of the ring If the value of q is Q x find the value of x

2 Two coherent monochromatic point sources S and S of wavelength 600 nm are placed symmetrically on either side of the centre of the circle as shown The sources are separated by a distance d 1 8 mm This arrangement produces interference fringes visible as alternate bright and dark spots on the circumference of the circle Total and Pis number of fringes produced between P close to S P A0 S P 2

Width of a river is 60m A swimmer wants to cross the river such that he reaches from A to B directly Point B is 45m ahead of line AC perpendicular to river Assume speed of river and speed of swimmer as equal Swimmer must try to swim at angle 8 with line AC Value of 0 is C 1 2 Question Type Single Correct Type 3 37 53 0 30 A B River Flow

A parallel monochromatic beam of light is incident normally on a narrow slit A diffraction pattern is formed on a screen placed perpendicular to the direction of the incident beam At the first minimum of the diffraction pattern the phase difference between the rays coming from the two edges of the slit is 1998 A O C T B 2 D 2

The side of a cubical block when measured with vernier calipers is 2 50 cm The vernier constant is 0 01 cm The maximum possible error in the area of one face in cm is 1 0 01 3 0 05 2 0 02 4 0 10

A baseball pitcher delivers a fastball that crosses the plate at an angle of 6 93 degrees below the horizontal and a speed of 80 9 mph The ball mass 0 142 kg is hit back over the head of the pitcher at an angle of 35 67 degrees above the horizontal and a speed of 108 1 mph What is the magnitude of the impulse received by the ball

Ray Optics and Optical Instruments 10 Find the deviation caused by a prism having 3 refracting angle 4 and refractive index 2 3 3 2 11 From the graph of angle of deviation versus angle

posit charged When light travels from glass to air the incident angle is 0 and the refracted angle is 0 Then the correct relation between two angles is 1 0 0 2 0 0 3 0 0 4 Not predictable

11 The surface tension of water is 75 dyne cm Find the mini mum vertical force required to pull a thin wire ring up refer figure if it is initially resting on a horizontal water surface The circumference of the ring is 20 cm and its weight is 0 1 N a 0 125 N b 0 225 N c 0 115 N d 0 130 N

A mono chromatic lightwave moves from one transparent medium to another The refractive index of the second medium is thrice the refractive index of the first medium If the wavelength of light in first medium is 6 x 10 7 m then the wave length of the lightwave in second medium would be 1 1 x 10 7m 2 2 x 10 7 m 4 18 x 10 7m 3 9 x 10 7 m

5 In general a current carrying copper wire is 1 Positively charged 3 Neutral 2 Negatively charged 4 Either negatively or positively charged

3 When a potential difference is applied across the ends of a linear metallic conductor 1 The free electrons are accelerated continuously from the lower potential end to the higher potential end of the conductor 2 The free electrons are accelerated continuously from the higher potential end to the lower potential end of the conductor 3 The free electrons acquire a constant average velocity from the lower potential end to the higher potential end of the conductor 4 The free electrons are set in motion from their position of rest

Activity of a radioactive element 1 103 dps Its half life is 1 second After 3 second its activity will be dps decay per second 1 1000 dps 2 250 dps 4 None of these 3 125 dps

Three identical rods are welded to form a U shaped rigid structure as shown It is hinged at point A The angle made by rod AB with vertical in equilibrium position is 0 Find the value of tane A B 0

A person is unable to see an object beyond 30cm Find the power of lens in dioptre to correct the vision 1 3 10 3 20 3 2 4 10 3 20 3 7

3 15cm 4 30cm Focal length of plano convex glass lens of refractive index 1 5 is 15cm A small object is placed at A as shown The plane surface is silvered The image will be formed at 20cm 1 60cm to the left of lens 2 12cm to the left of lens 3 60cm to the right of lens 743 2000

4 2 radian Q 19 When a clock is viewed in a mirror the needles exhibit a time which appears to be 8 20 Then the actual time will be 2 3 40 4 3 20 0 20 1 4 40 3 8 20

8 A 20gm bullet pierces through a plate of mass M 1kg and then comes to rest inside a second plate of mass M 2 98kg as shown in the figure It is found that the two plates ini tially at rest now move with equal velocities Find the per centage loss in the initial velocity of the bullet when its is between M and M Neglect any loss of material of the plates due to the action of bullet V m a 50 100 u M m b 25 d 75 u V M

0 Assertion When monochromatic light is incident on a surface separating two media the reflecte and refracted light both have the same frequency as the frequency of incident light Reason The frequency of monochromatic light depends on media 1 Both assertion and reason are true 3 Both assertion and reason are false 2 Assertion is true but reason is false 4 Assertion is false but reason is true

A pendulum with a length of precisely 1 37 m can be used to measure the acceleration due to gravity g Such a device is called a gravimeter a How long do 100 oscillations take at sea level where g 9 81 m s S Suppose you take a gravimeter to a spot on Venus where the value of g is 0 9 less than the value of g at sea level on Earth How long do 100 oscillations take at this place on Venus S You have a stopwatch that can measure time differences of 0 15 s How many oscillations would you need to be able to measure the gravitational difference

to bring it to rest in 10 revolutions the 29 A cylinder rotating at an angular speed of 50 rev s is brought in contact with an identical stationary cylinder Because of the kinetic friction torques act on the two cylinders accelerating stationary one and decelerating the moving one If the common magnitude of the acceleration and deceleration be one revolution per second square how long will it take before the two cylinders have equal angular speed 36

If under the action of applied forces a block is displaced by 10 m towards right as shown in figure Then the work done by 50 N force is 1 1000 J 50 N 2 1000 J 3 500 J 100 N 4 500 J

Two astronauts are floating in gravitational free space after having lost contact with their spaceship The two will a move towards each other b move away from each other c will become stationary d keep floating at the same distance between them NEET 2017

process in which pressure and temperature of gas vary such that P CT where C is constant If Heat is supplied then Answer A Rate this question Your Attempt Correct answer C Internal energy decreases B Internal Energy increases C Temperature decreases Internal oporgy romain samo

There is a retarding force of specific magnitude to stop train If the speed of the train is doubled how far will this retarding force stop the train a 10 times b 2 times c 6 times d 4 times

30 In a quink tube experiment a tuning fork of frequency 300 Hz is vibrated at one end It is observed that intensity decreases from maximum to 50 of its maximum value as tube is moved by 6 25 cm Velocity of sound is m s

54 Lenz s law is a consequence of the law of conservation of 1 momentum 2 charge 3 mass 55 In general a current carrying copper wire is 4 energy

A person holds a uniform 0 1 kg metre stick horizontally between fore finger and thumb in such a way that the thumb is at the end of the meter stick and the finger is 30 mm from it The forces exerted by the thumb and fore finger act vertically as shown in the diagram below Calculate the force exerted by the thumb When performing the calculations please ensure you include all additional forces and distances to the diagram Ffore finger 30 mm Fthumb 1 m

68 In producing chlorine by electrolysis 100 power at 125 V is being consumed How much chlorine per minute is liberated E C E of chlorine is 0 367 x 10 6 kg a 1 76 10 kg c 17 61 x 100 kg b 9 67 10 kg 3 d 3 67 x 10 kg

There are two plane mirror inclined at 40 as shown in the figure A ray of light is incident on mirror M then what should be the value of angle of incidence i so that the light ray retraces its path after striking the mirror M M O 70 O 40 O 50 60 40 M Marks 4 1

A small sphere having radius R and made up of material of density p falls from rest vertically from a height h into a liquid of density 3p The period of oscillation is O O 2 2h 9 2h 9 O 2h 9 3h 9

In the figure shown a block of mass 10 kg is resting on the inclined plane of inclination 37 Two forces F and F parallel to incline plane are applied on the block in the directions shown If coefficient of friction is 0 5 a is acceleration of block and f the value of friction match the List I II 2 List I I I a 0 II a 1 m s III a 2 m s IV a 4 m s 37 A I S II T U III Q IV R C I Q S II P U III R IV T List II II P F 20 N F 10 N Q F 30 N F 10 N F 40 N F 40 N R S F 100 N F 70 N T F 80 N F 100 N U F 110 N F ON B I P II T U III R IV S D I S II Q U III R IV P

0 A ray of light incidents normally on a plane mirror Then the angle of reflection will be 3 between 0 and 45 4 it will not reflect 1 0 2 90 1 A conducting rod AB moves parallel to X axis in a uniform magnetic field pointing in the positive

If a tension in a string is 6 4 N A load at the lower end of a string is 0 1 kg the length of string is 6 m then find its angular velocity g 10 m s A 3 rad s C 2 rad s B D MH CET 2008 4 rad s 1 rad s

A paralleled plate capacitor has circular plate of diameter 5mm and separation between the plate is 2mm a Calculate the capacitance of the capacitor b Find the charge on each plate of the capacitor when battery of 16Vis connected c What is the electric field between the capacitor plates when a material is filled in the space between plates has dielectric constant of 6

A current i ampere flows in a circular arc of wire whose radius is R which subtend an angle 3 2 radian at its centre The magnetic induction B at the centre is 2 40 R 3 oi 8R O Moi R O Moi 2R R x 2 Marks 4 1