Physics Questions

1 20 Find the electric field strength vector at the centre of a Vball of radius R with volume charge density p ar where a is a constant vector and r is a radius vector drawn from the ball s centre Ans E 1 6a R

Two batteries of emf s 5V each and internal resistance R R R R respectively are connected in series with wires having negligible resistance Then A V V V Ve 0 V V 0 B V V 0 V Vc 0 VA VB 0 R

ash me ans violet dia hai hat is correct In white light interference nearest to the central bright fringe will have which of the following colour 1 violet 2 yellow red 4 green EW00047

A satellite is moving in a low nearly circular orbit around the earth Its radius is roughly equal to that of the earth s radius Re By firing rockets attached to it its speed is instantaneously increased in the direction of its motion so that it become A 2Re C 4Re 3 122 larger Due to this the farthest distance from the centre of the earth that the satellite reaches is R Value of R is B 3Re D 2 5Re times

The potential energy of each 2uF capacitor is 1 J and that of the 6 F capacitor is 2 J Find i the potential difference between A B ii the potential energy of the upper capacitor

A particle is thrown horizontally with speed 10 m s along the rim of a smooth fixed cylinder of height 20m Taking g 10 m s2 the time taken by the particle to reach the bottom assuming it to be always in contact with the cylinder is in sec 10m s 20m

1 55 A positive charge Q is fixed at a point A Another positively charged particle of mass m and charge q is projected from a point B with velocity u as shown in the figure 1 459 The point B is at large distance from A and at distance d from the line AC The initial velocity is parallel to the line AC The point C is at very large distance from A Find the minimum distance in meter of q from Q during the motion Take Qq 4 mud and d 2 1 meter Q 1 1 1 B C d

A hollow copper tube is filled completely using a steel rod The rod and tube are joined by two rivet pins as shown in the figure d d 2 Y Steel rivets Steel Copper Temperature of assembly is raised by AT after setting the rivets Now choose the correct options a Stress in copper oc tube d Strain in copper tube 1 3 ocu You Stress in steel steel tube b Stress in copper tube Stress in steel tube c Strain in steel tube steel AT 20 AT Cu

Apparent dip at a place is always greater than or equal to the value of true dip at that place This is due to 1 Increase in apparent value of B 2 Decrease in apparent value of B 3 Increase in apparent value of B 4 Both 1 2

A parallel plate capacitor of area 60 cm and separation 3 mm is charged initially to 90 C If the medium between the plates gets slightly conducting and the plate loses the charge initially at the rate of 2 5 10 C s then what is the magnetic field between the plates B 2 0x10 T 2013 A 2 5 10 T C 1 63x10 1 T L D zero

A body is thrown vertically upward its velocity and acceleration at top respectively are 0 0 0 g 0 g g g A body is projected vertically up from ground neglecting air friction Which of the graph best shows the variation of speed v with time i 2 1

3 45 Initially the switch is in position 1 for a long time in the circuit shown in figure 3 397 At t 0 the switch is moved from 1 to 2 Obtain expressions for Vand VR for t 0 S THI 24 50V Figure 3 397 Ans V 50 3e 200 1 VR 150e 200r 5kn 1 F

34 Two long and parallel straight wires A and B carrying currents of 4A and 2A in the same direction are separated by a distance of 2 cm The force on a 10 cm section of wire A is 1 8 10 5 N 3 8 x 10 6 N 2 8 10 N X 4 8 108 N

angle 80 A particle is fired with with the horizontal What is the magnitude of change in velocity when it returns to the ground 1 u cos 0 2 u 3 2u sin 0 4 u cos0 u 181 In the above the change in speed is 1 u cos 0 2 0 3 u sin 0 4 u cose u

Two planets have masses M and 16 M and their radii are a and 2a respectively The separation between the centres of one planets is 10a A body of mass m is fired from the surface of the larger planet towards the smaller planet along the line joining their centres For the body to be able to reach at the surface of smaller planet the minimum firing speed needed is GM GM2 B A 2 C a 3 5GM D 4 ma GM

49 A simple pendulum oscillator has an amplitude A and time period T The time required by it to trave from x A to x 1 A 2 dan m gu vra vilas e Adx x 2 T 6 is 2 T 4 3 T 3 4 T 2

moment u is rotated to the direction of done is sine cos0 toward earth e deflected 49 4 tan 14 3 Magnetic moment of a bar magnet shown in figure i is M S N S N 55 Fig 1 Fig ii If a hole is drilled through the magnet as shown in figure ii then new magnetic moment of the magnet will be 1 Equal to M 2 Less than M TAS Zem 3 B A com hc zo will 1 2 56

A magnet when suspended at an angle of 30 to magnetic meridian the dip needle makes an angle 45 with horizontal The dip angle measured in magnetic meridian will be O 1 tan 3 tan 1 3 1 2 tan 3 3 2 8 Pusa Road New Delhi 110005 Ph 011 47623456 2 3 4 tan 1

metic meridian the at the place is Magnetism and Matter 299 The horizontal component of the earth s magnetic field at a place is 3 x 10 4 T and the dip is 3 tan A metal rod of length 0 25 m placed in the north south position and is moved at a constant speed of 10 cm s towards the east The emf induced across the length of rod will be 1 Zero 2 1 V LAX 10 V

3 As shown in figure the key K is closed the direction of the induced current in the coil B will be A O B In 1 clockwise and momentary 2 anticlockwise and momentary 3 clockwise and continuous 4 anticlockwise and continuous K

Q4 The refractive index of vitreous humor in our eye ball is 1 34 Visible light of wavelength ranges from 402 rim to 670 nm as measured in air The wavelength range just approaches retina within vitreous humor is O A 280 nm to 480 nm O B 300 nm to 500 nm O C 340 nm to 540 nm O D 320 nm to 520 nm

clinic lines A magnetic needle makes n oscillations per minute in a horizontal plane where angle of dip is 45 If needle is made to oscillate in a vertical plane coinciding with the magnetic meridian then number of oscillations per minute will become remain 1 n 2 2n 3 2 4 n 4 n 2 wer 8 Pusa Road New Delhi 110005 Ph 011 47623456

A Ball coming back to Projection Point A ball is projected with a velocity u at an elevation from a point distance d from a smooth vertical wall in a plane perpendicular to it After rebounding from the wall it returns to the point of projection If e is the coefficient of restitution between ball and wall find the maximum distance d for which ball will come back to the projection point

illustration 9 A converging lens of focal length 15 cm and a converging mirror of focal le 20 cm are placed with their principal axes coinciding Point object is placed at a distance 12 from the lens Refracted ray from the lens gets reflected from the mirror and again refracte the lens It is found that the final ray coming out of the lens is parallel to the principal axis the distance between the mirror and the lens Solution Focal point of lens F F Focal point of mirror N LM TXA M Applying Gauss formula to le 1 1 1 V 12 x 15 12 15 u f Using cartesian sign conventi 60 cm P

2 The length of each side of a cubical closed surface is 1 If charge q is situated on one of the vertices of the cube then find the flux passing through shaded face of the cube

2 A parallel plate capacitor after charging is kept connected to a battery and the plates are pulled apart with the help of insulating handles Now which of the following qunatity will remain constant f 1 Charge 1 2 Capacitance 2 f 3 Energy stored 3 f 4 Potential difference 4 fawaid

The gap between the plates of a paralle I plate capacitor of area A and distance between plates d is filled with a dielectric whose permittivity varies linearly from at one plate to 2 at the other The capacitance of capacitor is 80 8 8 A A C d A din 2 B D o A 2d 80 8 A din 2014

Seven resistor are connected as shown in circuit The equivalent resistance in ohms of this network between A and B and a fa A 7B H87 H Y G 3 NH N G 1 6 A 2 8 1002 wwww 300 www www 602 80 www www 402 www 1002 3 12 www B 892 4 20

6 A particle moves along a straight line such that its displacement at any time t is given by S t 6t2 3t 4 metres The velocity when the acceleration is zero is Ra S t 612 3t 4 1 3 ms 1 2 12 ms 1 3 42 ms 1 4 9 ms 1

d the voltage e voltmeter ng V A micrometer has a resistance of 10002 and full scale deflection current of 50 A How can it be made to work as an ammeter of range 5mA By connecting 102 resistance in parallel with it

Under the action of a force a 2kg body moves such that its position x as a function of time is given by X O 16 J O 16 J O 160 J 23 where x is in metre and t in seconds The work done by force in first two secon

3 1 Two parallel plate capacitor of capacitance 2C and Care charged to the potentials 2V and V respectively and are connected in a circuit along with a resistance R as shown in the diagram The switch k is closed at t 0 Find the current in the circuit as a function of time and total heat produced in the circuit SR 2C 2V F F C V Figure 3 372 k

Four cells and six resistances are connected as shown in the figure Then CO MAZZA 30 B 1202 www 12V 802 ww www del 3 The magnitude of current through 80 resistor connected between the points B and E is 1A The magnitude of current through 80 resistor connected between the points B and E is 1 5A The potential difference between the points B and D is 20V Potential at D is greater than that at B

ii A cell of EMF 3 4V and internal resistance 30 is connected to an ammeter having resistance 202 and to an external resistance of 10052 When a voltmeter is connected across the 10002 resistance the ammeter reading is 0 04A Find the voltage read by the voltmeter and its resistance Had the voltmeter been an ideal one what would have been its reading C 40002 3 2V 3 238V 2

A particle of mass m connected to a string of length l which is rotating in a vertical circle such that the ratio of the maximum to the minimum tension in the string is 2 1 then find out the speed of the particle at the bottom most point O 13ge 12ge O 11ge 10ge

In the given figure the coefficient of friction between 4kg and 5 kg blocks is 0 2 and between 5 kg block and ground is 0 1 respectively Choose the correct statements f4kg 5 kg 2 0 2 5 kg 0 1 1 Minimum force needed to cause system to move is 17 N 2 When force is 4N static friction at all surfaces is 4N to keep system at rest 3 Maximum acceleration of 4kg block is 2m s 4 Slipping between 4kg and 5 kg blocks start when F is 17N 1 fa fa 17 2 N fay Art HER F 3 4kgm s 4 F 17 N 4kg 75 kg FREM GR V I Q P 4kg 5kg mi

A block of mass m initially at rest is dropped from a height h on to a spring of force constant k The maximum compression in the spring is x then mgh kx 2 mg h x kx 2 mgh k x h 2 mg h x k x h 2

Figure shows a smooth curved track terminating in a smooth horizontal part A spring of spring constant 25 N m is attached of 5 m on the curved track Find the maximum compression in m of the spring g 10 m s 5m one end to a wedge fixed rigidly with the horizontal part A 1kg mass is released from rest at a height

space between the plates of a parallel plate capacitor is filled with a dielectric whose dielectric constant varies with distance as per the relation K x K 2x a constant The capacitance C of this capacitor would be related to its vacuum capacitance Co as per the relation A C 6 c 2d In 1 K d 2d In 1 2d Ko Co Co B C D C d In 1 K d d In 1 Ko 2d Co Co 2014

marks A train starts from rest at t 0 along a straight track with a constant acceleration of 5 m s A passenger at rest in train observes a particle of mass 1 kg on the floor with which it has a coefficient of friction us Uk 0 6 Att s a horizontal force F 13 N is applied on the particle for 2s duration The passenger observes that the particle is now moving in a perpendicular direction of motion of the train g 10 m s 5 1 13 The magnitude of acceleration of the particle with respect to the ground at t 5 sec is 61 m s with the direction of motion of the train The direction in which force F 13 N is applied is at cos The momentum of the particle at t 6 sec with respect to the train is 12 kg m s The momentum of the particle at t 6 sec with respect to the train is 6 kg m s

apan ne 2 303 nRT log V2 V1 ye kyu nahi use kiya Iska sahi ans PV se aara h Ka Under isothermal condition a gas at 300 K expands from 0 11 to 0 25L against a constant external pressure of 2 bar The work done by the gas is Given that 1L bar 100 J 1 30 J 2 5kJ 3 25 J 4 30 J A compound is formed by cation C and anion A

Marking scheme 4 for correct answer 0 if not attempted and 1 in all other cases 5 A hollow cylinder of radius 4R is rotating about fixed horizontal axis passing through point O with angular velocity A solid cylinder of radius R is rolling without slipping with respect to inner surface of hollow cylinder At the given instant the line OC has angular velocity of 20 Point A and B are topmost and bottom most points c solid cylinder respectively and C is its centre Then at the given instant 80

A uniform rope of mass 2 kg and length 4 m connecting two blocks is placed on frictionless horizontal ground The block of mass 3 kg is pulled by a 27 N force as shown in the figure What is tension in newtons at a point 1 away from the 1 kg block 50 3 kg 27 N

Question 1 Single Select Type A battery of emf 16V and internal resistance 20is connected across a long uniform wire AB of length 1m and resistance per unit length 20m Two cells of emf 5 11 and 2 are connected as shown in the figure If the galvanometer shows no deflection at point P the distance of point P from point A is equal to 16V 213 101 00 50 cm 20 100 cm

13 If a nucleus is emitting e particle its neutron to proton ratio will eff 1 increase 1 G n 2 decrease 2 Pr 3 remain unchanged THIG FE 4 can t be determined He 4

In cosmic shower an electron is falling toward earth near equator In which direction will it be deflected 1 Eastward 2 Westward 3 Northward 4 Southward in maximum for

A small conducting circular loop is placed inside a long solenoid carrying a current The plane of the loop contains the axis of the solenoid If the current in the solenoid is varied the current induced in the loop is a clockwise b anti clockwise c zero d clockwise or anti clockwise depending on whether the or decrea

Ask an Expert What is the moment of inertia of a magnet in the topic of dipole in uniform magnetic field Where is the axis for the magnet in this topic Then what is the formula for the moment of inertia of a magnet Jul 27 2021 12 15 49 PM Answer PFA IN S Answered MXB ms sino ton magnet 1 At equilibriure Id 0 MB and de 2 indicata

State whether the following statements are true T or false F Correct the false statements 1 A simple machine makes work easier by providing energy on its own T 2 Class II lever works like a force multiplier T 3 The smaller the lead of a screw the higher is the mechanical advantage T 4 A movable pulley reduces the effort used to pull the load T 5 The wheel and axle must move alternately to form a simple machine F 6 The efficiency of every machine used by us is always equal to 100 F

3 A system consists of two identical particles One particle is at rest and the other particle has an acceleratio a The centre of mass of the system has an acceleration of Uchaf FORUT 1 2a 2 a 3 a a 4 he a of