Basic Physics Questions and Answers

The line graph given below shows the sales of three car companies A B and C during the period 2005 2010 What is the approximate growth percentage of total sales of three companies from 2005 to 2010 Sales in units 4000 3500 3000 2500 2000 1500 1000 500 0 2005 2006 2007 2008 2009 2010 Year A B C

66 An electric dipole of moment P is released in a uniform electric field E from the position of maximum torque Angular speed of the dipole when P becomes parallel to E will be moment of inertia of dipole T PE 21 3 2PE 4PE 2 4 PE 2 DE m

B 1 1 x 1 x be an ordered basis of polynomials in P Write down the coordinate vector of the polynomial asis in the form a b c 7 points Save Answer 1 2x x 2 relative to this given

14 A convex lens forms a real image on the screen with magnification m If lens is moved a distance x again a real image is formed with magnification m Then focal length of the lens is 1 X 3 xlm m l 2 Jm m X m m

9 Which method is used to induce an emf or current in a loop in AC generator a A change in the loop s orientation b A change in its effective area c Both a and b d Neither a nor b

In the figure shown calculate the linear acceleration of the blocks Mass of block A 10 kg Mass of block B 8 kg Mass of disc shaped pulley 2 kg Take g 2 kg Take g 10 m s Consider sufficient friction at the surface of pulley LUULLU LLL B A

their volumes is least the diameter of sphe 41 A given quantity of metal is to be cast into a half cylinder with a rectangular base and semicircular ends Show that in order that the total surface area may be minimum the ratio of the length of the cylinder to the diameter of its semi circular ends is 2 Thos the product of its breadth and square of its donth T 30

V3 4 N3P 32 A machine gun of mass 10kg fires 10gm bullets at the rate of two every second Each bullet comes out with a vel ocity of 200 m s The velocity of recoil of the gun at the end of the fourth second after firing starts is 1 1 6 m s 2 0 8 m s 3 3 2 m s 4 2 0 m s

An impulse 30 Ns is given to the block of mass 2 kg in downward direction as shown in the figure As a result of the impulse A both the blocks start moving with 5 m s in opposite directions B Centre of mass of the system is moving upward C the net impulse acting on the block of mass 2 kg is 10 Ns D the net impulse acting on the block of mass 4 kg is 10 Ns 4 kg 2 kg

Yellow light is used in a single slit diffraction experiment with slit width of 0 6 mm If yellow light is replaced by X rays then the observed pattern will reveal A that the central maximum is narrower C less number of fringes B more number of fringes D no diffraction pattern 1999

Set a five rupee coin on a stiff card covering an empty glass tumbler standing on a table as shown in Fig 9 7 Give the card a sharp horizontal flick with a finger If we do it fast then the card shoots away allowing the coin to fall vertically into the glass tumbler due to its inertia The inertia of the coin tries to maintain its state of rest even when the card flows off

35 Two co axial metallic long cylindrical shell carry current of equal magnitude in opposite direction If the radii of the cylinders are a and b a then which plot represents the variation of magnetic field with the distance r from the axis of the cylinder 1 3 AB r ar br AB r a r b 2 4 AB AB 1 r a r b

For a submerged plane in a liquid the resultant hydrostatic force F on one side of a plane is related to area A centroidal depth yC depth of centre of pressure yp and the depth of bottom edge yb as Option 1 F w Ayp Option 2 F wA yc yp Option 3 F w Ayc Option 4 F w Ayb

5 points The equation E k s r3 represents the magnitude of Select one O Electric force of point charge O Electric field at location on the dipole axis O Electric field at location on the perpendicular to dipole axis O Electric field of point charge

A bucket that has a mass of 25 kg when filled with sand needs to be lifted to the top of a 20 mete tall building You have a rope that has a mass of 0 1 kg m that must be secured to the bucket It takes 1 meter of rope to secure the bucket Once the bucket reaches the top of the building it onl has mass 22 kg because there was a hole in the bottom and sand was leaking out at a constant r while it was being lifted to the top of the building Find the work done lifting the bucket sand and rope to the top of the building

29 In the two positions of the lens keeping distance between object and screen fixed size of the image is 4 cm and 9 cm The size of the object is 1 5 cm 2 13 cm 3 6 cm 4 9 6 cm

Question 5 A series RLC circuit containing inductance a resistance of 600 an of 100mH and a capacitor of 100uF are connected in series across a 100V 50Hz supply Calculate the total circuit impedance the circuits current power factor and draw the voltage phasor diagram

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

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

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

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

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

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

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

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

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

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

A number of projectiles each with same speed u are fired at different angles lying between 0 and 90 as shown Neglecting air resistance and assuming g to be constant then the equation of the envelop E of the parabolic trajectories as shown in figure is Y C E 92 O 27

In the diagram shown below wavefront and AO and BP the corresponding two rays The condition of 0 for constructive interference at P between the ray BP and reflected ray OP is Nd then N is cose 02 Q C A R d X P

Q No 2 Luvit your un upevne VIL VI RIVAL THAN THE ECO super omnes For each question choose the option s corresponding to all the correct answer s Answer to each question will be evaluated according to the following marking scheme Full Marks 4 If only all the correct option s is are chosen Partial Marks 3 2 Partial Marks Partial Marks Zero Marks 1 0 Negative Marks 2 For Example If first third and fourth are the ONLY three correct options for a question with second option being an incorrect option selecting only all the three correct options will result in 4 marks Selecting only two of the three correct options e g the first and fourth options without selecting any incorrect option second option in this case will result in 2 marks Selecting only one of the three correct options either first or third or fourth option without selecting any incorrect option second option in this case will result in 1 marks Selecting any incorrect option s second option in this case with or without selection of any correct option s will result in 2 marks D If all the four options are correct but ONLY three options are chosen If three or more options are correct but ONLY two options are chosen and both of which are correct If two or more options are correct but ONLY one option is chosen and it is a correct option If none of the options is chosen i e the question is unanswered In all other cases A ring of mass 2m and radius R is set into pure rolling on horizontal rough surface in a uniform magnetic field of strength B as shown in the figure A point charge q of negligible mass is attached to rolling ring Friction is sufficient so that it does not slip at any point of its motion 8 is measured in clockwise from positive y axis x x x x2mx x x x x x x x x 9x x x x x x X X X X X XXXXXXX X X X X X X X X X X XX X X X X X X X X X X X X www XXX X X X X X X X X X 0 X X Ring will continue to move with constant kinetic energy is 2mv The torque of friction about center of ring is BqvRcose Dino View In English V XX X

52 A point object P is placed at 0 0 and a plane mirror M is placed inclined 30 with the x axis then the position coordinates of image is 2 3 15 1 0 30 3 4 mmm 3 3

A wooden stick of length L radius R and density P has a small metal piece of mass m of negligible volume attached to its one end The minimum value for the mass m in terms of given parameters that would make the stick float vertically in stable equilibrium in a liquid of density KR 2 P 1 Find the value of K if the rod is not submerged completely in the liquid O is T LP O O O 1 2 4

a b 4r 2r Y 2 40 A circular coil of radius R carries an electric current The magnetic field due to the coil at a point on the axis at a distance x from the centre of coil is th of the magnetic field at the centre of coil 8 Value of x is a R b 2R c 2R d 3R

5 refractive index RI to another 3 medium at an angle 30 The angle of 5 refraction for other medium is sin 6 then the increase in angle of incidence is such that the ray of light reflected back 1

A body of radius R and radius of gyration K about axis of rotation is rolling without slipping The fraction of its kinetic energy is in form of rotational kinetic energy is 1 R2 K R K R 1 X R

A small spher density p falls from rest vertically from a height h into a liquid of density 3 P The period of oscillation is O O O 3 A 2 2h 9 2h 9 2h 9 3h

Select the correct option about the friction between the two bodies 1 Static friction is always greater than the kinetic friction Limiting friction is always greater than the kinetic friction 3 Limiting friction is not always greater than the kinetic friction 4 The direction of friction is always opposite to motion

A rock is thrown upward from a bridge that is 38 feet above a road The rock reaches its maximum height above the road 0 51 seconds after it is thrown and contacts the road 3 15 seconds after it was thrown Write a function f that determines the rock s height above the road in feet in terms of the number of seconds t since the rock was thrown

1 10 km h at 0 Column I 1 2 3 2 5 3 km h at 60 3 10 3 km h at 30 4 5 3 km h at 30 Column II P 53 If swimmer can swim at 5m sec in still water and if velocity of water flow is 4m sec then angle between direction of swimming and direction of river flow to minimize drift If swimmer can swim at 5m sec in still water and velocity of flow is 3m sec then angle between direction of velocity of swimmer with respect to river and the direction of river flow if swimmer crosses the river in minimum time If swimmer can swim at 4 m sec and velocity of flow is 3m sec then angle of resultant velocity w r t ground with the direction of river flow if swimmer heads perpendicular to flow of river Angle between direction of fluttering of flag and north if wind blows towards south west direction with a velocity 3 2 m sec Man moves with a velocity 7m sec along west holding flag in his hand Q 127 R 143 S 90

A block of mass M is held against a rough vertical wall by pressing it with a finger If the coefficient of friction between the block and the wall is and acceleration due to gravity is g the minimum force required to be applied by the finger to hold the block against wall is 1 3 Mg Mg M 1 2 Mg 4 1 Mg

horizontal position as shown For what value of angle between string and vertical during its motion the total acceleration is directed horizontally O O O 90 0 90 1 COS Sin 1 3 1

Problem 6 Two speakers separated by a distance of 3 30m both pointing towards a wall in front of them A person standing against the wall between the speakers Position A hears destructive interference If the observer hears constructive interference after moving 0 80 m to one side of the wall what is the frequency emitted by the speaker Assume the air velocity is 343 m s

Tangential acceleration of a particle moving on a circular path of radius 1 m varies with time as shown The time after which total acceleration makes an angle of 45 with the velocity of particle is particle starts from rest a m s 1 4 s 1 43 S S LS S 60 2 t s 4 1 4 3 S 2 3 S

If an electromagnetic wave has a frequency of 1 46 x 1012 Hertz calculate the wavelength in meters Enter the answer using scientific notation Spaces are not allowed For example if the answer is 1 23 x 107 enter it as 1 2367 And if the answer is 4 56 x 108 enter it as 4 56e 8 Give the answer to three significant figures

1 The dispersive powers of crown and filint glasses are 0 02 and 0 04 respectively In an achromatic combination of lenses the focal length of flint glass lens is 40 cm The focal length of crown glass lens will be a 20cm c 10cm b 20cm d 10cm