Physics Questions

17 In the arrangement shown the magnitude of each resistance is 12 The equivalent resistance between O and A is given by a 75 a b 17 02 c B D 275 352

A physical quantity of the dimensions of length that can be e formed out of c G and is c is velocity of light G 4 0 is universal constant of gravitation and e is charge 2017 200 G a e 4 EO 71 2 71 2 0 4 42 102 1 e G47 b c 648 G d G e 71 2 C 47 E

45 A person travels the total distance in two parts in the ratio 2 1 with a constant speed of 30 km h in the first part and 40 km h in the second part What is the average speed of the journey

In Young s double slit experiment two slits are illuminated with separation between them as b The screen is at a distance d b from slits At a point P on the screen directly in front of one of the slits certain wavelengths are missing Match the options of the columns Column I A At P wavelength b d is B At P wavelength b 5d is C D The wavelength 26 3d at a point on screen at some other distance b 3 from central maxima Column II P missing Q not missing Wavelength 2b 3d is R X b missing at a point Q on screen which is at a distance X from central maxima S X 3b 4

A loaded spring gun of mass M fires a bullet of mass m with a velocity v at an angle of elevation 0 The is initially at rest on a horizontal smooth surface After firing the centre of mass of the gun and gun bullet system a moves with velocity b moves with velocity c remains at rest d moves with velocity M m vm M cos 0 in the horizontal direction v M m M m in the horizontal direction string passing over fixed pulley Assume

Two point charges of 0 2 C and 0 2 C are separated by 108 m Determine the electric field a an axial point at a distance of 0 1 m from thei midpoint Use the standard value of Eo

In R L C series AC circuit the potential differences across each element is 20 V Now the value of the resistance alone is doubled then potential differences across R L and C respectively become 1 20 V 10 V 10 V 2 20 V 20 V 20 V 4 10 V 20 V 20 V 3 20 V 40 V 40 V

In a Young s double slit experiment the fringe width will remain same if D distance between screen and plane of slits d separation between two slits and wavelength of light used Bihar MEE 1995 a Both and D are doubled b Both d and D are doubled c Dis doubled but d is halved d 2 is doubled but d is halved 1

40 electric bulbs are connected in series across a 220 V supply After one bulb is fused the remaining 39 are connected again in series across the same supply The illumination will be a more with 40 bulbs than with 39 b more with 39 bulbs than with 40 c equal in both the cases d in the ratio 402 392 1989

C Long answer questions 1 Explain how you would measure the volume of an irregular solid say a stone 2 Explain how you would measure the area of an irregular shape using a square centimetre grid 3 Describe how the density of a solid can be determined Numerical questions 1 Convert 3000 mL into L Ans 3 L 2 The volume of water in a measuring cylinder is 52 mL After dropping a stone into it the water level increases to 63 mL Find the volume of the stone Ans 11 mL or 11 cm 3 Find the area of a a book of length 20 cm and breadth 10 cm and b a table of length 1 5 m and breadth 20 cm Ans a 200 cm b 3000 cm or 0 3 m 4 An object of area 15 cm and height 2 cm has a mass of 50 g What is its density in SI system Ans 1667 kg m 5 A bullet is shot from a rifle with a speed of 720 m s How much time is required for the bullet to strike a target 3240 m away Ans 4 5 s

A positive charge is uniformly distributed along a circular ring of radius R A small test charge qis placed at the centre of the ring Then q ON A If q 0 and is displaced away from the centre in the plane of the ring it will be pushed back towards the centre B If q 0 and is displaced away from the centre in the plane of the ring it will never return to the centre and will continue moving till it hits the ring C If q 0 it will perform SHM for small displacement along the axis D q at the centre of the ring is in an unstable equilibrium within the plane of the ring for q 0 E 19 36

3 When a rubber band is stretched by a distance x it exerts a restoring force of magnitude F ax bx where a and b are constants The work done in stretching the unstretched rubber band by Lis D aL2 bL3 IIT Mains 2014 A aL bL aL bL 2 3 C A wire which passes through the hole in a small h B 1aL bL3 2 3

139 A closed organ pipe has length A The air in it is vibrating in 3rd overtone with maximum amplitude a The amplitude at a distance of 2 7 from closed end of the pipe a a 5 b a 2 1

The terminal potential difference of a cell is greater than its emf when it is a being discharged b open circuit c being charged d being either charged or discharged

A body starts from rest on a long inclined plane of slope 45 The coefficient of fiction between the body and the plane varies as 0 3 x where x is the distance travelled down the plane The body will have maximum speed for g 10 m s when x 1 9 8 m tang M 2 12 m 3 12 m 4 3 33m tan 45 0 3x x 100 2013

particle is projected with velocity 30 above on an inclined plane inclination of which from horizontal is 37 Choose propriate path air resistance is negligible U 30 37 b U 30 37 c u 30 37 d u 30 37

Consider a simple pendulum having a bob attached to a string that oscillations under the action of force of gravity Suppose that period of oscillations of the simple pendulum depends on its length I mass of the bob m and acceleration due to gravity g Derive the expression for the time period using method of dimensions

A thin rod of length L is lying along the x axis with its ends n mass length varies with x ask where n can be zero or any positive number If the position XCM of the centre of mass of the rod is plotted against n which of the following graphs best E 2008 approximates the dependence of XCM on n XCM 1 L L 2 L L 2 O XCM n 2 4 XCM L 2 XCM L L 2 O n n ular disc of radius R is removed from a bigger circular disc of radius 2R such that th ferences of the discs coincide The centre of mass of the new disc is aR from the centre ger disc The value of a is

We measure the period of oscillation of a simple pendulum In successi Measurements the readings turn out to be 2 63 S 2 56 S 2 42 S 2 71 and 2 80 S Calculate the absolute errors relative error and percentag

hematics All the graphs below are intended to represent the same motion One of them does it incorrectly Pick it up 1 2018 U ve 3 velocity distance L Slope 0 a ve time U 0 Uitve time 1 0 a ve 4 velocity Physics 3 position position time Parabola U tve a ve

A ray of light travelling parallel to diameter of a sphere enters the sphere through a hole at point A as shown in the figure The inner surface of the sphere is made perfectly reflecting Find the number of reflections suffered by the ray before coming out of the sphere A 180 C 179 B 20 D 19 90

15 Figure shows electric field lines in which an electric dipole p is placed as shown Which of the following statements is correct NCERT Exemplar 9 P q a The dipole will not experience any force b The dipole will experience a force towards right c The dipole will experience a force towards left d The dipole will experience a force upwards

Two identical charges are placed at a separation of 1 0 m What should be the magnitude of each charge so that each one repels the other with a force of 36 kg wt 8 10 mS

A weight W rests on rough horizontal plane If the angle of friction be 0 then calculate the least horizontal force that will move the body along the plane Osnca let

6 A physical quantity x depends on quantities y and z as follows x Ay B tan Cz where A B and C are constants Which of the following do not have the same dimensions a x and B c y and B A b C and z 1 d x and A

0 A body of mass 2kg is froo to movo along x axis It is at rost at t subjected to a time dependent force F t in x direction The variation of F with time is as sh Haryana NTSE Stage 1 2 F 1 AN 0 2N 35 4 55 The change in momentum during journey is in N s A 4 50 B 7 50 C 5 06 D 14 06

Example 4 13 Evaluate the magnitude and direction of magnetic field at point O in the following cases i a

The switch S is closed at t 0 Just after closing the switch reading of ideal Voltmeter and reading of ideal Ammeter are V volt and I amp respectively The final readings of devices are V volt and 12 amp given R 52 R R3 102 L 10 mH A The value of i is 1 amp V V 1 21 C The value of is 2 ohm 30 V S R www R3 wwww R L 66000000000000 B The value of i is 2 amp V V is 4 ohm 4 21 D The value of

A cricket ball of mass 150 g is moving with a velocity of 12 m s and is hit by a bat so that the bal gets turned back with a velocity of 20 m s If the duration of contact between the ball and bat is 0 01 s find the impulse and the average force exerted on the ball by the bat lution According to given problem change in momentum of the ball Ap Pf Pi m v u 150 x 10 3 20 12 So by impulse momentum theorem Impulse I Ap 4 8 N s And by time average definition of force in case of impulse Fav I Ap 4 80 480N

23 In the situation shown the currents through 3 22 and 2 2 resistances are in the ratio 19 www A 39 www 2 7 4 www 49 292 wwwww www 59 3 AY

32 In the situation shown the potential difference across the cell of smaller e m f is 1 2 V 2 4 V 3 Zero 4 6 V 2 V 19 www 10 V www 192 www 292

ball is thrown at angle a 90 a 0 on inclined plane as shown in figure then the minimum speed of the ball during the otion is YA UK

d low 1 A circuit contains a capacitor and inductance each with negligible resistance The capacitor is initially charged and the charging battery is disconnected At subsequent time the charge on the capacitor will b decrease exponentially a increase exponentially d remain constant c decrease linearly for limiting

A ring of radius 0 25 metre and mass 10 kg rotating about its diameter with angular spe 40 rad s Its kinetic energy is 1 5 J 2 50 J 3 250 J 4 500 J

R in R 32 In the situation shown the potential difference across the cell of smaller e m f is 2 V 19 ww 10 V ww 202

In vector form Biot Savart s lat Idlx r Ho dB oc 4 K or 3 From Eq i the direction of the cross product vector d 1 the right handed screw rule c Here d B is perpendicular to is directed inwards since p current element Magnetic field induction at entire wire is B Ho 4 Id Ho Id B Ho

Single 7 1 A U tube of base length filled with same volume of two liquids of densities p and 2p is moving with an acceleration a on the horizontal plane If the height difference between the two surfaces open to atmosphere becomes zero then the height h is given by L A l B 3a 2g l 860 g a

8 A convex lens of focal length f 10 cm is cut through a dimeteral plane into two semicircular halves In doing so glass of 0 5 mm thickness is lost The two halves are then joined together This lens is placed symmetrically 5 cm in front of a slit which is illuminated with light of wavelength 5000 A A screen is placed on the other side of the lens at a distance of 90 cm from the lens perpendicular to the optical axis of the lens Find total number of bright fringes formed

Find the equivalent capacitance of the combination shown in Fig 2 85 between the points A and B 10 5 9 Cs HH SI C Ans C B 2G G G G

23 The appropriate M versus magnetization magnetising field H curve for a paramagnetic substance is most a A b B c C d D MA 0 C A B D H

A body is thrown vertically upwards Which one of the following graphs correctly represen2017 velocity vs time V 4 V f V U gt a ve edge of a cliff 240 m high with initial speed of time variation of

1012 A wave of length 2m is superposed on its reflected wave to form a stationary wave A node is located at x 3m The next node will be located at x 1 3 25 m 2 3 50 m 3 3 75 m 44m

A hollow spherical ball of inner radius a and outer radius 2a is made of a uniform material of constant thermal conductivity K The temperature within the ball is maintained at 2T and outside the ball it is T Find a the rate at which heat flows out of the ball in the steady state b the temperature at r 3a 2 where r is radial distance from the centre of shell Assume steady state condition AOL 0 2a a 2TO K T

13 Containers A B and C of equal volume contain oxygen neon and methane respectively at the same temperature and pressure The correct increasing order of their masses is a A B C c C A B 14 Average volume available to a molecule in a sample of a gas at STP is a 1 66 x 10 24 cm c 22400 cm b 3 72 x 10 20 cm d unpredictable 15 Pressure of a mixture of 4 g of O and 2 g of H confined in a bulb of 1 litre at 0 C is b 31 205 atm 105 a 25 215 atm c 45 215 atm d 15 210 atm 16 Which of the following volume V temperature T plots represents the behaviour of one mole of an ideal gas at one atmospheric pressure V L V L 4 22 4 L 273 K V L A 2105 is to 22 4 L 273 K b B C A d C B A to 1012 36 8 Ls 373 K a 22 4 L 273 K T K V L 4 2100 125 30 6 L3 B 373 K te c 22 4 L 273 K ban 28 6 L 373 K b T K T K mov d is T K Kerala PET 2007 AIIMS 2005 17 Containers A and B have same gas Pressure volume and temperature of A are all twice that of the number of molecules of A 14 2 L 373 K

28 A physical quantity is a physical property of a phenomenon body or subs by measurement 34 The magnitude of the components of a vector are to be considered dimensionally distinct For example rather than an undifferentiated length unit L we may represent length in the x direction as L and so forth This requirement stems ultimately from the requirement that each component of a physically meaningful equation scalar or vector must be dimensionally consistent As an example suppose we wish to calculate the drift S of a swimmer crossing a river flowing with velocity V and of width D and he is swimming in direction perpendicular to the river flow with velocity V relative to river L T assuming no use of directed lengths the quantities of interest are then V V both dimensioned as S the drift and D width of river both having dimension L With these four quantities we may conclude that the equation for the drift S may be written So VaVbDc y Or dimensionally L x L from which may deduce that a b c 1 and a b 0 which leaves one of these exponents undetermined If however we use directed length dimensions then V will be dimensioned as Ly V as S as L and D as L The dimensional equation T T becomes L a b and we L and we may solve completely as a 1 b 1 and c 1 The increase in deductive power gained by the use of directed length dimensions is apparent Which of the following is not a physical quantity A Height of a boy C Fever of a boy A R 29 From the concept of directed dimension what is the formula for a range R of a cannon ball when it is fired with vertical velocity component V and a horizontal velocity component V assuming it is fired on a flat surface Range also depends upon acceleration due to gravity g and k is numerical constant k V V g B R B Weight of a boy D Speed of a running boy k V g R C R k V Vyg D R k V V g

A solid conducting sphere having net charge Q and radius 3 a contains a hollowed spherical region of radius 2 a A point charge Q is placed at a distance a from the common center of the spheres What is the magnitude of the electric field at the position r 4 a from the center of the spheres as marked in the figure by P a kQ a 16a 3kQ b 16 a Q 1 1 1 P kQ c 8a d can t be determined due to non uniform distribution

J A stone projected at angle 0 with horizontal from the roof of a tal building falls on the ground after three second Two second after the projection it was again at the level of projection Then the height of the building is 1 5 m 4 15 m 2 25 m 3 20 m

Three point charges 9 92 and q3 are taken such that when q and q2 are placed close together to form a single point charge the force on q3 at distance L from this combination is a repulsion of 2 unit magnitude When q2 and q3 are combined the force on q from same distance L is of magnitude 4 unit and is attractive Also q3 and q combining exerts a force of magnitude 18 unit in q2 from same distance L Algebraic ratio of charges q 92 and q3 is b 2 3 4 d 4 3 2 a 1 2 3 c 4 3 1

15 Two stones are projected from level ground Trajectories of two stones are shown in figure Both stones have same maximum heights above level ground as shown Let T and T be their time of flights and u and u be their speeds of projection respectively neglect air resistance Then COLT 2 3 l U U Yoordinale same for al 4

Example 9 4 Suppose while sitting in a parked car you notice a Jogger approaching towards you in the side view mirror of R 2 m If the jogger is running at a speed of 5 m s how fast the image of the Jogger appear to move when the jogger is a 39 m b 29 m c 19 m and d 9 m away Solution From the mirror equation Eq 9 7 we get fu u f For convex mirror since R 2 m 1 m Then 39 x1 39 39 1 40 for u 39 m U Since the jogger moves at a constant speed of 5 m s after 1 s the position of the image v for u 39 5 34 is 34 35 m The shift in the position of image in 1 s is 39 34 1365 1360 5 1 40 35 1400 1400 280 Therefore the average speed of the image when the jogger is between 39 m and 34 m from the mirror is 1 280 m s Similarly it can be seen that for u 29 m 19 m and 9 m the speed with which the image appears to move is 1 10 100 m m 1 150 Although the jogger has been moving with a constant speed the speed of his her image appears to increase substantially as he she moves closer to the mirror This phenomenon can be noticed by any person sitting in a stationary car or a bus In caso of simil 1 ms ms and ms respectively 60