Physics Questions

A narrow smooth tunnel of L shapes is made into earth upto central as shown in the figure A small ball which just fits in tunnel is released from A The collision of ball is perfectly inelastic g is acceleration due to gravity on surface of planet 0 RAR 3k Time to fall from A to B is Time to fall from B too T R 2Vg 7 R 4Vg Speed just before hitting B is DSpeed just before hitting O is 4Rg 5 VR Rg 5 VR

128 Potential difference between A and B in the figure shown is 6 V 12 1 2 V 3 8 V 292 ww A www ww 3 9 X 109 ww 2V ww 39 192 2 8 V 4 2 V 4 V

A body of mass 1 kg is moving in a vertica circular path of radius 1 m The differenc between the kinetic energies at its highest an lowest position is 1 20 J FI 2 10 J 4 106 5 1 J

The focal length of spherical mirror if the object distance u 50 1 0 5 cm and image distance V 20 1 0 2 cm will be 1 12 2 0 2 cm 3 10 2 0 1 cm 2 14 3 0 1 cm 4 15 1 0 3 cm

PASSAGE I Two cars A and B travel in a straight line The distance of A from the starting point is given as a function of time by xA t at t with a 2 60 m s and 1 20 m s The distance of B from the starting point is xB t yt St with y 2 80 m s and 8 0 20 m s 1 2 Which car is ahead just after they leave the starting point a Car A moves ahead b Car B moves ahead c Car A and B moves simultaneously d Data is insufficient to decide At what time s are the cars at the same point a 2 27 s b 5 73 s c 2 6 s

Example 3 70 An open lift is moving upwards with velocity 10 ms It has an upward acceleration of 2 ms 2 A ball is relative to ground projected upwards with velocity 20 ms Find 1 i time when ball again meets the lift ii displacement of lift and ball at that instant iii distance travelled by the ball upto that instant Take g 10 ms 2

B 1 An advertisement claims that a certain 1200kg car can accelerate from rest to a speed of 25 m s in a time of 8s What average power must the motor produce to cause this accoloration 2 1 Int

29 In the LR circuit shown what is the variation of the current I as a function of time The switch is closed at time t 0 sec 2V A 1 1 R 1 eL V Rt L 0000 Rt R 3V R ww V B Rt e L None

Four metallic plates each with a surface area of one side A are placed at a distance d form each other The alternating plates are connected to points A and B as shown in the figure Then the capacitance of the system is A 80 A B 280A d C B 38 A d D 480A d

40 3 2 kg of ice at 10 C just melts with m mass of steam at 100 C then m is equal to cal g CA Sice 0 5 1 800 g 3 425 g IEW 2 625 g 4 325 g

A compass needle whose magnetic moment is 60 Am is pointing geographical north at a certain place whereas the horizontal component of the Earth s magnetic field is 40 Wb m and experiences a torque of 1 2 x 10 3 Nm What is the declination of the place

relative density of wooden piece 1516 3 A piece of wood of uniform cross section and 15 cm height sinks 10 cm in water and 12 cm in spirit Find the relative densities of wood and spirit 4 A block of wood is kept on a tabletop The mass of wooden block is 5 kg and its dimensions are xorted by the wooden block on the tabletop if it is made

BEGINNER S BOX 9 If two forces act in opposite direction then their resultant is 10N and if they act mutually perpendicu their resultant is 50N Find the magnitudes of both the forces

Area of cross section of plane circular coil makes twice keeping it number of turns same then percantage increases in its self inductance 1 41 4 3 200 2 141 4 4 100

Categorise the following function of time cos ot as a S H M b Periodic but not S H M Also find the period Hint cos wf 3 cos wt cos3wt 4

Consider a uniform electric field 3 x 10 i NC 1 Calculate the flux of this field through a square surface of area 10 cm when 2 i its plane is parallel to the y z plane and ii the normal to its plane makes a 60 angle with the raxis

4 8 sec The equation of S H M is y sin 2 nt a then its phase at time t is 1 2nt 2 4 nt 3 2 nt a 4 4 nt 2a A particle executing S H M along y axis has its motion described by the equation y A sinot B the amplitude of S H M is

Q5 Two plane mirrors are placed parallel to each other at a separation of 6m as shown in figure Find the Xit number of images of the object O separation between 5th image 6 m O www 2 m

a c 1 04 d 0 98 2010 33 The potential difference that must be applied to stop the fastest photoelectrons emitted by a nickel surface having work function 5 01 eV when ultraviolet light of 200 nm falls on it must be 34 a 2 4 V c 2 4 V When b 1 2 V d 1 2 V motic dieti 2010

D For the structure shown in figure moment of about an axis passing through yy is 1 2ML 3 2 45 45 2L 2 ML 3 4ML

In Young s double slit experiment the slits are 0 5 mm apart and interference pattern is observed on a screen placed at a distance of 1 0 m from the plane containing the slits If wavelength of the incident light is 6000 then the separation between the third bright fringe and the central maxima is AMU 1995 a 4 0 mm c 3 0 mm b 3 5 mm d 2 5 mm

Graph is plotted between photo current 1 and applied voltage V Then maximum kinetic energy of emitted electron will be 1 2 eV 4 3 2 1 0 1 V 2 4 eV 2 3 4 3 0 eV 4 1 eV BOAI BO PHYSICS BOON Z E MODERN PHYS Z WODE02 BOA BO PHYSICS AT A GLANCE CROPEN E screen will be 1 0 9 L 3 0 4

Two particles P and Q are projected simultaneously away from each other from a point A as shown in figure The velocity of P relative to Qin ms at the instant when the motion of P is horizontal is 1 10 4 3 3 10 14 Q 20 ms 1 45 A 2 20 4 3 4 20 4 3 PA 20 ms 60

I mass m and side r 26 ABC is an equilateral triangular frame It is at rest under the action of horizontal magnetic field B as shown and the gravitational field 0 B T B r 3 3 1 The frame remains at rest if the current in the frame is 2mg rB 2 The frame remains at rest if the current in the frame is 2mg rB 3 71 2 3 The frame is in simple harmonic motion when frame is slightly displaced in its plane perpendicular to AB The r 3 period of oscillation is g 4 For same as in above option the period of oscillation is 71 2 3r 2g

ma 13 On an object of mass 1 kg moving along x axis with constant speed 8 m s a constant force 2 N is applied in positive y direction Find its speed after 4 seconds

A lens of focal length f is cut along the diameter into two identical halves In this process a layer of the lens t in thickness is lost then the halves are put together to form a composite lens In between the focal plane and the composite lens a narrow slit is placed near the focal plane The slit is emitting monochromatic light with wavelength 2 Behind the lens a screen is located at a distance L from it S d S S V 114 L

A particle of mass m is executing oscillation about the origin on the x axis Its potential energy is U x K x 3 where k is a positive constant If the amplitude of oscillation is a then its time period Tis Eska 2 2 1 2mv 1 alf K 3Kx 2 tom 3k ma Proportional to 2 Proportional to a 3 3 Proportional a

When the N pole of a bar magnet points towards the south and S pole towards the north the null points are on the 1 magnetic axis 2 magnetic centre 3 perpendicular division of magnetic axis 4 N and S pole

If displacement of a particle is zero the distances covered 1 must be zero 2 may or may not be zero 3 cannot be zero 4 depends upon the particle

Two persons P and Q crosses the river starting from point A on one side to exactly opposite point B on the other bank of the river The person P crosses the river in the shortest path The person Q crosses the river in shortest time and walks back to point B Velocity of river is 3 kmph and speed of each boat is 5 kmph w r t river If the two persons reach the point B in the same time then the speed of walk of Q is 08 Imp

1 Figure shows the electric lines of force emerging from a charged body If the electric field at A and B are E A and EB respectively and if the distance between A and Bis r then A r B C

4 similar rods which are thermally insulated are joined at point A If heat flows in from point B at rate of 1W and from point C at 3W inside flows out from D at 5W which relation is correct for temperature of these points A TA TE B TB Tc B C X E D C Tc TD D TB TE

1 PHYSICS In closed end pipe of length 105 cm standing waves are set up corresponding to the third overtone What distance from the closed end amongst the following is a pressure node 1 20 cm 2 60 cm 3 85 cm 4 45 cm The tension length diameter and density of a string B are double than that of another string A Which fundamental frequency of A the strings are fixed

friction between the striker and board is 0 2 The coordinate of the striker when it stops taking point O to be the origin is 1 1 2 2 2 1 2 0 2m s 1 2 X 1 2 0 2 2 2 2 1 1 4 2 2 2 5 10 Particle A moves with speed 10 m s in a frictionless circular fixed horizontal pipe of radius 5 m and strikes with B of double mass that of A Coefficient of restitution is 1 2 and particle A starts its journey at t 0 The time at which second collision occurs is t 0 1 3 A KIN 5N S Fixed B 2 2 4 4 s

C 74 In Young s double slit experiment angular width of fringes is 0 20 for sodium light of wavelength 5890 If complete system is dipped in water then angular width of fringes becomes RPET 1997 a 0 11 c 0 22 b 0 15 d 0 30 between

10 A body is dropped from the top of a tower at height 100 m Simultaneously another body is thrown up with a velocity 40 m s When and where they meet

Figure 3 24 gives the x t plot of a particle in one dimensional motion Three different equal intervals of time are shown In which interval is the average speed greatest and in which is it the least Give the sign of average velocity for each interval X 1 2

Quiz Quiz If earth were to stop spinning then your weight on equator will be A B C D heavier by around 0 5 heavier by around 5 less by around 0 5 less by around 5

Two mirrors are inclined at an angle 0 as shown in the figure Light ray is incident pal mirrors Light will start retracing its path after third reflection if A 0 45 B 0 30 0 C 0 60 D all three

If F sin0 2cose of Fis 1 coco A 1 then the minimum positive value 2 4 3 4 2 3 60

Two parallel slits 0 6 mm apart are illuminated by light source of wavelength 6000 The distance between two consecutive dark fringes on a screen 1 m away from the slits is JIPMER 1999 a 1 mm c 0 1 m b 0 01 mm d 10 m

A particle moves along a circular arc of radius R making an angle of 0 at centre The magnitude of displacemen a 2R sin 0 2 b 2R sin 0 c R sin 0 2 d Rsine

A particle has initial velocity V i j and a constant force F i j acts on the particle The path of the particle is 1 straight line 3 circular 2 parabolic 4 elliptical

23 A rod PQ of mass M and length L is hinged at end P The rod is kept horizontal by a massless string tied to point Q as shown in figure When string is cut the initial angular acceleration of the rod is 3g PC k a 9 L o 2g Q d NEET 2013 2g

NEET PHY Q 21 A hollow sphere is released from the top of a wedge as shown in the figure There is no friction between the wedge the ground There is sufficient friction to provide pure rolling The velocity of the sphere just before it leaves the wedge will be Assume Masses of the wedge and sphere are equal h R to be the radius of sphere Om 1 3gh 7 h m 2 49h 3 gh 6 6

In the given arrangement the charge on the 3 F capacitor is 2 F HE T 10V 3 F the fur HH 1 F

The internal resistance of a cell of e m f 2 V is 0 1 Q2 It is connected to a resistance of 3 9 2 The voltage across the cell will be a 1 95 V b 1 9 V c 0 5 V d 2 V 1999

Two small balls having the same mass and charge and located on the same vertical at heights h and h are thrown in the same direction along the horizontal at the same velocity v The first ball touches the ground at a horizontal distance R from the initial vertical position At what height he will the second ball be at this instant Neglect any frictional resistance of air and the effect of any induced charges on the ground

4 A is false But Ris 39 When a bar magnet is suspended freely in a uniform magnetic field identify the correct statements a The magnet experiences only couple and undergoes only rotatory motion b The direction of torque is along the suspension wire c The magnitude of torque is maximum when the magnet is normal to the field direction 1 only a and care correct 2 only a and b are correct 3 only b and care correct

A55 kg man holds a weight of 20 kg on his head W is the work done by him against gravity if he moves distance of 20 m i on a horizontal road ii on Encline of 1 in 5 Take g 10 m s2