Physics Questions

Which of the following is the feature of switch 4 It operates on physical layer It broadcasts data to every computer or Ethernet based device connected to it It is an intelligent network device that can be conceived as a multiport network bridg O When a packet arrives at one port it is copied to the other ports so that all segments of the LAN can see all packets

A block of mass m is kept over a rough board such that it is connected to a spring whose other end is also fixed to the board The board is lifted slowly to increase the inclination with horizontal The graph that best represents the variation of elongation in spring with 0 is X 3 XA XA 0 Horizontal 0 mt00000000 0 XA 2 0 V 1 XA 4 A

Centre of Mass of a Gas An ideal gas of molar mass M is contained in a very tall cylindrical vessel in the uniform gravitational field in which free fall acceleration is g Assuming the gas temperature is T find the height at which centre of mass of gas is located sad all prish

268 A projectile is thrown with a speed u at an angle 0 to the horizontal The radius of curvature of its trajectory when the velocity vector of the projectile makes an angle a with the horizontal is TAMANNA CHAUDHARY 4

A certain number of spherical drops of a liquid of radius r coalesce to form a single drop of radius R and volume V If T is the surface tension of the liquid then 2014 energy 4VT is released R r energy 3VT is absorbed R energy 3VT 1 1 r is released Incorrect Correct

Three particles having masses m 2m 3m respectively are attached by three springs constants k 2 k and 2k respectively as shown find out accelearatiob of each block ju st after cutting from A B C D E an d F as shown in figure retched If the 4 what will be the an acceleration e block A on t

The electric field at the surface of a positively charged spherical conductor with surface charge density of C m and a 1 J radius of 1 m decreases by a factor of 2 if x number of electrons are added to its surface The value of x in unit of 10 2 is A 0 125

60 A short bar magnet placed in a horizontal plane has its axis aligned along the magnetic north south direction Null points are found on the axis of the magnet at 14 x 10 2 m from the centre of the magnet The earth s magnetic field at the place is 0 36 x 10 4T and the angle of dip is zero What is the total magnetic field on the normal bisector of the magnet at the same distance as the null points i e 14 x 10 m from the centre of the magnet If the bar magnet is turned around by 180 where will the new null points be located N C E R T New Ans 0 54 x 10 4 T at 11 11 x 10 2 m on the perpendicular bisector 10 2m and its total number of turns is 2400 An iron rod is placed inside 1 co

An equiconvex lens is made of material which has a refrac tive index of 1 6 for blue light and 1 5 for red light Its focal length for red light is 0 20 m The ratio of focal length for red light to focal length for blue light is 0 01N Find the value of N

Solve this Q Find the electric potential at the point O due to segment of ring as shown in figure whose linear charge density is 4 C m y K 1 3 8 10 2 V 2 3 8 10 0 v 3 4 8 10 0 V 4 4 8 10 2 V 60 R 4m

tion 5 The reason that freshly laundered laundry does not touch the ground is that proportional to the weight of the laundry but in the opposite direction O O The string exert action The floss exert the action The string exotic reaction The cloth exert reaction

An electron travelling east to west enters a chamber having a uniform electrostatic field in south to north direction If electron is not deflecting from its straight line path then the direction of a uniform magnetic field B is fa 1 Vertically upward UU N 2 Vertically downward 3 Towards North you 4 Towards South NE yo VD f 10 A is

A signal of 5 kHz frequency is amplitude modulated on a carrier wave of frequency 2 MHz The frequencies of the resultant signal is are a 2005 kHz 2000 kHz and 1995 kHz b 2000 kHz and 1995 kHz c 2 MHz only d 2005 kHz and 1995 kHz

24 force should act on the body at an angle 30 to the horizontal so that the body just begins to move 25 3 A body of mass 0 1 kg is pressed against a wall with a horizontal force 5 N If coefficient of friction is 0 5 then find force of friction TL US N MS 3x253 ico with a velocity of 8 m s comes to rest after travelling 40 m Find the coefficient of

When a body is in pure rolling on a horizontal surface A its point of contact slips with respect to the surface its point of contact moves with the speed and acceleration of the surface its centre of mass moves along a straight line D its top most point always move faster than the lowest point of contact

A boy of mass m standing on a block of mass M which in turn lying on a rough surface of coefficient of static friction Boy is pulling him through pulley system shown in the figure The maximum force he can exert so that block does not slip 1 m M m g 2 l M m9 mM M m g 1 4 4 M m g 1 u

0 The mass of a body is 200 g Keeping 7 part of its volume exposed to air the body is floating in mercury If the specific gravity of mercury is 13 6 then what wil be the specific gravity of the body 6 4

ater ent s A A powerful man pushes a wall and the wall gets deformed The magnitude of force exerted E the wall on man will be equal to the magnitude of force exerted by man on the wall B Ten person are pulling horizontally an object on a smooth horizontal surface in differe directions The resultant acceleration of the object is zero Then the pull of each man is equal to the resultant pull of the other nine men C A massless object cannot exert force on any other object D All contact forces are electromagnetic in nature

The temperature reduces as the height incre ases Therefore the density in the higher ho rizons of the atmosphere might be more tha n the lower ones But it is not so because of gravity But why the assumption I made is w rong

Bu B Br An infinitely long wire is bent at 90 at point O 25 as shown in figure Match the following Table I Table II A Magnetic field at P P inwards B Magnetic field at Q Q outwards 1 A P B Q S 3 A R B Q S I R TEXT SERIES R S 10 1 4x r 2 A P S B Q S 4 None of these van ser end and O 3 BB B B 4 B B B B v far segen 90 farg fear ffera B A P B Table I 1 A P B Q S 3 A R B Q S 45 P R S Table II 2n r 47 T 2 A PS B Q S 4 340

Assume that we don t neglect the angle between the axis of rotation and perpendicular to the orbit As venus moves to the diametrically opposite point in it s orbit the axis of the rotation is will be tilted in which manner A C O Sun O Sun B D OSun O Sun O Sun

Q 12 In a certain double slit experimental arrangement interference fringes of width 1 0 mm each are observed when light of wavelength 5000 is used Keeping the set up unaltered if the source is replaced by another of wavelength 6000 the fringe width will be 1 0 5 mm 3 1 2 mm 2 1 00 mm 4 1 5 mm

Q 27 A U tube having uniform cross section but unequal arm length 1 rm length 1 100 cm and 1 50 cm has same liquid of density p filled in it upto a height h 30 cm as shown in figure Another liquid of density P2 2p is poured in arm A Both liquids are immiscible The length of the second liquid is in cm should be poured in A so that second overtone of A is in unison with fundamental tone of B Neglect end correction A h P14 B

R L elle 12 E R S R3 In the circuit shown the switch S has been open for a very long time It is suddenly closed at time t 0 Data E 180 V L 0 25 H C 4 10 F R 50 R 600 R3 a Find the current i on the emf device at time t 0 A 40 22 i 0 b Find the rate of change of the current on the inductor at time t 0 diz A s dt c Find the current i on the emf device at time t 0 i 0 A d Find the charge on the upper plate of the capacitor at time t o q 0 C

A convex lens of focal length f and dispersive power w is combined with a concave lens of focal length f2 and dispersive power 02 is such a way that an achromatic doublet of focal length 40 cm is obtained If respectively 40 3 1 2 20 3 40 3 4 20 20 40 3 20 40 2 W2 3 then f and f2 in cm are

During the propagation of electromagnetic waves in a me dium a Both electric and magnetic energy densities are zero b Electric energy density is double of the magnetic en ergy density c Electric energy density is half of the magnetic energy density d Electric energy density is equal to the magnetic energy density

A man is running with a constant acceleration on a plate which is placed on a horizontal smoot surface Then choose the correct option s A Work done by friction on the man is negative P Work done by friction on the man is positive C Work done by friction on the plank is positive D work done by friction on the plank is negative

A ray of light of intensity I is incident on a parallel glass slab at a point A as shown in fig It undergoes partial reflection and refraction At each reflection 25 of incident energy is reflected The rays AB and A B undergo interference The ratio Imax Imin is B A B C 4 1 8 1 7 1 A B

tions 04 Variation in Loud Variation in Loudness Level in a medium In a homogeneous medium loudness level of sound is different at different locations and it varies between 30 dB and 43 98 dB If in medium only two sonic waves of same frequencies but of different amplitudes exist from a single source Calculate the intensities of these two waves de live whe

A perfect capacito nected in parallel to a variable frequency sinusoi dal alternating voltage supply At resonance the impedance of the circuit is 1 Lw 3 zero 2 4 1 Co infinite wz

1 A wooden wedge of mass M and inclination angle a rest on a smooth floor A block of mass m is kept on wedge A force F is applied on the wedge as shown in the figure such that block d remains stationary with magnitude of force F is a M m g tan a c mg cos a F4 M respect to wedge So b g tan a d M m g cosec a

Q 11 Two plane mirrors are parallel to each other and spaced 20 cm apart An object is kept in between them at 15 cm from A Out of the following at which point image is not formed in mirror A distance measured from mirror A 1 15 cm 3 45 cm 2 25 cm 4 55 cm

5 Monochromatic light is incident on a glass prism of angle A If the refractive index of the material of the prism is a ray incident at an angle 0 on the face AB would get transmitted through the face AC of the prism provided a 0 cosusin A sin 2 b 0 cos usin A sin7 c sinusin A sin d 0 sin usin A sin OI B C

Two charged thin infinite plane sheets of uniform surface charge density and where lo lol intersect at right angle Which of the following best represents the electric field lines for this system A C 0 0 B D 62211 FRR111 0

An elastic ring of mass m and force constant k stiffness is released from rest in a smooth cone of semi vertex angle 0 from horizontal position as shown in figure Initially the ring was in natural length A initial acceleration of any point on circumference of ring is g B initial acceleration of centre of ring is g cos 0 mg cot 0 2 k D at the moment maximum vertical displacement acceleration of centre of ring is zero C maximum vertical displacement of centre of ring is ring g

site signs ar ts downward increased a P is din a An emf of 15 volt is app 5 henry inductance and 10 92 resistance The ratio of the current at time t and t 1 s is e 1 2 1 6 A 31 A e e 1 3 1 e 1 4 e 1 If the armature resistance of a simple electric motor is 292 and runs at 24 volt It draws a current of 2A when the motor is unloaded But when it is connected with load then its speed reduces by 10 of its initial value The current taken by the loaded motor is 2 2 A 4 3 A Assertion Reason Type Que In the following questions a statem A is followed by a statement of 1 if both Assertion Rea reason is the correc assertion then mark SECTION 2 If both Assertion reason is not the assertion then m 3 If Assertion is false then ma 4 If both Ass statements 17 There are two coaxial solenoids S and S S surrounds S number of tums length are n and n radius r and r respectively If length of solenoids f mutual inductance is A The back R The cha motor 22 A The to c tra

luced A square loop enters a magnetic field with velocity v as shown in figure The front edge enters the magnetic field at time t 0 Which of the following graphs gives the correct variation of emf e induced in the loop with time t for its constant velocity in the magnetic field 1 3 1 2 A D t s 2 P t s 4 A rectangular metal loop ABCD is passed through ne magnetic field with a constant velocity v Which of the following represents power P vs time t graph B C V X X X X of dip is 45 B X t s t s X X X X X X X X X X 53 4 Self inductance of a solenoid is 5 mH If current is decreasing through it at the rate 103 A s then emf induced in the solenoid is 1 5 V 2 5 V 3 2 5 V 4 2 5 V Keeping number of turns constant self inductance L of a solenoid varies with its length las 1 LI 2 Lax 3 La R La 7 12 2 4 La b A conducting rod AC of length 41 is rotated with angular velocity w about a point O in a uniform magnetic field B directed into the plane of the paper If AO 1 and OC 31 then potential difference between A and C V Vis X x x X x x Ax X x S se X X X O X X x v X x X X X x 1 2Bw 2 Bw 3 3Bw 4 4Bw Tower 8 Pusa Road New Delhi 110005 Ph

Gas Pressure variation with height An ideal gas of molar mass M is located in uniform gravitational field in whi the free fall acceleration is g Find gas pressure as a function of height if gas temperature varies with height T T 1 ah At h 0 take pressure of gas be Po

Calculate the moment of inertia of the shape about the indicated axis 5 00 30 00 15 00 17 50 17 50 5 00 1 y 2 10 00 3 5 00

2 9 In copper each copper atom releases one electron If a current of 1 1 A is flowing in the copper wire of uniform cross sectional area of diameter 1 mm then drift velocity of electrons will approximately be Density of copper 9 x 10 kg m Atomic weight of copper 63 1 10 3 mm s 3 0 2 mm s 2 0 1 mm s 4 02 cm la

Particle A of mass m 3 with another particle B at rest having mass m 20 m 2 2 C A 2 moving along the x axis with velocity v collides elasticall axis after the collision the change AX in de Broglie wavelength of particle A in terms o its de Broglie wavelength 20 before collision is A A2 m 3 If both particles move along the x 5 B A2 20 2 D AX 420

Ans given is 3rd but when I solved it by Nernst equation my ans is 0 29V Calculate EMF of the cell A A3 0 1M B2 0 01 M B Given E 0 75 V 1 R A A3 0 45 V E B B 1 2 3 4 0 30 V 1 21 V 0 26 V 0 80 V

Air in a sealed syringe is slowly compressed by moving the piston The temperature of the air stays the same D air syringe Which statement about the air is correct A The pressure of the air decreases because its molecules now travel more slowly B The pressure of the air decreases because the area of the syringe walls is now smaller C The pressure of the air increases because its molecules now hit the syringe walls more frequently The pressure of the air increases because its molecules now travel more quickly H piston

The velocity vector of a particle moving in xy plane is given by v ti xj If initially the particle wa at origin then the equation of trajectory of th projectile is 1 2x 9y 0 3 2x 9y 0 2 9x 2y 0 4 9x 2y 0

A tuning fork A produces 4 beats s with another tuning fork B of frequency 320 Hz On filling one of the prongs of A 4 beats s are again heard when sounded with the same fork B Then the frequency of the fork A before filing is A 328 Hz B 316 Hz C 324 Hz D 320 Hz Correct Answer Your Answer

0 A truck is stationary and has a bob suspended by a light string in a frame attached to the truck The truck suddenly moves to the right with an acceleration of a The pendulum will tilt NEET 2019 Odisha 1 to the left and angle of inclination of the pendulum with the vertical is sin g 2 to the left and angle of inclination of the pendulum with the vertical is tan a g 3 to the left and angle of inclination of the pendulum with the vertical is sin a g 4 to the left and angle of inclination of the a

The figure shows a block of mass m placed on a smooth wedge of mass M Calculate the value of M and tension in the string so that the block of mass m will move vertically downward with acceleration 10 m s Take g 10 m s A the value of M is B the value of M C the value of tension in the string is Mcote 1 cot 0 Mtane 1 tane D the value of tension is ug cota Mg tane M M m Smooth 87

4 53 A closed curve encircles several conductors The line integral B di around this curve is 3 83 x 10 7T m a What is the net current in the conductors b If you were to integrate around the curve in the opposite direction what would be the value of the line integral

RESPECTED SIR MAM FOR ME IT SEEMS TO BE SHORT CI RCUITED IN 4 CAPACITORS PLEASE EXPLAIN IT HOW TO C ONSIDER SHORTCIRCUIT IN CAPACITOR AND RESISTOR AL SO 25 Five capacitors are joined in a circuit as shown in the figure The capacitance of each capacitor is 1 4 F The equivalent capacitance between points A and B is GA A B 1 Zero 3 9 F 2 6 F 4 7 uF

lectricity charge on capacitor is t Zero Consider the circuit shown R is a variable resistance e is some unknown emf with polarity as shown Match the following B 202 6 V C 402 Column l A Current passing through 4 2 resistance can be zero B Current passing through 4 2 resistance can be from F to C direction C Current passing through 2 2 resistance will be from B to A direction D Current passing through resistance R will be from E to D direction p q R E 1 Column II Possible if e 6 Possible if e 6 r Possible if e 6 s Possible for any value of e Possible for any value of resistance R