Physics Questions

A biconvex thin lens of focal length 30 cm and aperture diameter 10 cm is broken into four identical pieces Two of the pieces are placed in a coordinate system as shown in the diagram Find the magnitude of the y coordinate of the image if an object is placed at origin 20 cm

Two pulley one 600 mm diameter and other INVO 300 mm diameter are on parallel shaft 3000 mm apart and are connected by a open belt Find the length of the belt required and angle of contact between the belt and pulley

The figure shows a RC circuit with a parallel plate capacitor Before switching on the circuit plate A of the capacitor was given a charge Q while plate B had no net charge Now at t 0 the circuit is switched on Time in seconds will elapse before the net charge on plate A becomes zero is K Value of 125K is Take C 1 F Q 1mC 1000 V and R 250 2x 108 In 3 Q R www A B L

Ith linear 1 31 A semi circular ring of mass charge density hinged at its centre is placed in a uniform electric field as shown in the figure 1 451 If the ring is slightly rotated about O and released find the time period in sec of oscillation Take m 8 kg 2 C m and E 2 N c Assume that coil is rotated in its own plane 0

A capacitor with charge Q on it is connected to an inductor L as shown in diagram at t 0 When the switch is flipped from position 1 to 2 the current in the circuit is observed to be at half of its maximum value Then 1 L 2 ellelle A Charge on capacitor at the time was Q 2 Q 3 2 Charge on capacitor at that time was C Total energy lost is Total energy lost is 4C 8C

You place a box of mass m 10 kg against a vertical wall You apply a constant force F to the box where F 200 N and the force is at an angle of 0 60 above the horizontal The coefficient of kinetic fric Blackboard Help n the book and the wall is 0 3 If the book is initially at rest what is its speed after it has traveled 0 5 m up the wall ALL e 3

Two sound waves of frequencies 100 Hz and 102 Hz and having same amplitude A are interfering A stationary detector which can detect waves of amplitude greater than or equal to A in a given time interval of 12 seconds find the total duration in which detector is active 8 2A Ao I I 1 1 6 s 1 4 s 1 3 s SSS cycle 2 3 sj 3 4 s 5 6 s SSS

Imagine that the electron in a hydrogen atom is replaced by a muon The mass of muon particle is 207 times that of an electron and charge is equal to the charge of an electron The ionization potential of this hydrogen atom will be 1 13 6eV 2 2815 2eV 3 331 2eV 4 27 2eV

8 A wire bent as a parabola y ax is located in a uniform magnetic field of induction B the vector B being perpendicular to the plane x y At the moment t 0 a connector starts sliding translationwise from the parabola apex with a constant acceleration w Fig 3 78 Find the emf of electromagnetic induction in the loop thus formed as a function of y y W Be O Fig 3 78 X A Om of nQ R R R B C Fig 3 79

mirror how would the screen have to be moved A 4 5 cm needle is placed 12 cm away from a convex mirror of focal length 15 cm Give the location of the image and the magnification Describe what happens as the needle is moved farther from the mirror parent

uestion Type Single Correct A Q No 6 This section contains SIX 06 questions Each question has FOUR options ONLY ONE of these four options is the correct answer For each question choose the option corresponding to the correct answer Answer to each question will be evaluated according to the following marking scheme Full Marks 3 If ONLY the correct option is chosen Zero Marks 0 If none of the options is chosen i e the question is unanswered Negative Marks 1 In all other cases When A B AB then A and B are perpendicular to each other A and B act in the same direction Marks For Correct Answer 3 00 and act in the opposite direction Negative Mark 1 00 View In English v 0 0

11 In a region of space suppose there exists a electric field 40x 1 The potential difference VA Vo is where Vo is the potential at the origin and VA the potential at x 2 m is 1 160 V 3 120 V 2 160 V 4 80 V

49 Maurine Lewis editor of a leading publishing house estimates that it takes 11 months on average To complete the process of publishing a book from having the manuscript until finished With a standard deviation of 2 4 months He thinks that the normal distribution describes well the distribution of publication times Of 19 books that will work this year approximately how many will complete the publication process in less than a year

Three blocks A B and C are placed on a rough horizontal surface Friction coefficient between blocks and surface is 0 6 Acceleration of the block C given situation is g 10 m s 4 kg A 6 kg B 3 5 m s O 0 5 m s O 4 5 m s O Zero C 5 5 kg

el in en iii A cylindrical layer of dielectric with dielectric constant k is inserted into a cylindrical capacitor to fill up all the space between the electrodes The mean radius of the electrodes is equal to R the gap between them is equal to d with d R A constant voltage Vis applied across the electrodes of the capacitor Find the magnitude of the electric force pulling the dielectric into the capacitor TRV F k 1 d

2 22 Two identical planar capacitor connected in parallel and charged to a voltage U 12V When you disconnect them from the voltage source the distance between the plates of one of the capacitors is reduced to one third of the original distance What will be the new voltage on the capacitors Ans 6V

An open train car with a mass of 21902190 kg coasts along a horizontal track at the speed 3 013 01 m s The car passes under a loading chute and as it does so gravel falls vertically into it for 3 373 37 s at the rate of 439439 kg s What is the car s speed vfvf after the loading is completed Ignore rolling friction

1 26 A non conducting hollow sphere having inner and outer radii a and b respectively is made of a material having di electric constant K and has uniformly distributed charge over its entire solid volume Volume density of charge is p Calculate potential at a distance r from its centre when

Aakash Rank Booster Test Series for NEET 2020 32 A thin mica sheet of thickness 2 x 10 6 m and refractive index u 1 5 is introduced in the path of the waves from upper slit in YDSE The wavelength of the wave used is 5000 A The central bright maximum will shift 1 2 fringes upwards 2 2 fringes downwards 3 10 fringes upwards 3

A compound microscope consist of an objective of focal length 2 cm and an eye piece of focal length 5 cm seperated by a distance of 15 cm How far should an object be placed from the objective in order to obtain in the final image at infinity 1 5 cm 2 10 cm 3 2 5 cm 4 None

9 Two short identical magnetic dipoles of magneti moments 1 Am each placed at a separation c 2 m with their axis perpendicular to each othe The resultant magnetic field at a point midwa between the dipoles is 1 5 x 10 7 T 3 10 7 T 2 5 x 10 7 T 4 5 5 x 10 7 T

1 36 A non conducting sphere of radius R 5 cm has its centre at origin O of co ordinate system shown in figure 1 453 It has a spherical cavity of radius r 1 cm whose centre is at 0 3 cm Solid material of sphere has uniform positive charge densit 10 6 C m Calculate potential at point P 4 cm 0 T p P X

4 Statement I When ultraviolet light is incident on a photocell its stopping potential is Vo and the maximum kinetic energy of the photoelectrons is Kmax When the ultraviolet light is replaced by X rays both Vo and Kmax increase Statement II Photoelectrons are emitted with speeds ranging from zero to a maximum value because of the range of frequencies present in the incident light

Aakash Rank Booster Test Series for NEET 2020 28 The length of the optical path of two media in contact of length d and d of refractive index Hy and H respectively is 1 d d d d M 9 A ray of light falls on a transparent sphere with 3 2 d H d d d H 4 4

3 1 Rnt 3 24 At a place on earth horizontal component of earth s magnetic field is B and B and vertical component of earth s magnetic field is B If a magnetic needle is kept in a vertical plane making an angle a with the magnetic meridian then square of time period of vibration needle in this plane is proportional to 1 B cos a 4 1 B cosa B 2 4 Rt

Homework Answered Four resistors are arranged as shown Calculate the electric potential difference through R Your answer should be in units of volts V Do not enter the units with your answer 2 0 4 0 5 00 7 00 www ww W R Ro R3 R4 A

7 A particle having charge q and mass m is released from rest on the axis of a fixed ring of total charge Q and radius R from a distance 3R Its kinetic energy when it reaches the centre of ring is 1 3 Qq 460R Qq 2R R 3R 2 ET Qq 86R Qq 16R

9 A lift is moving with velocity 10 m s upward with acceleration 5 m s2 upwards At the same instant of time a coin is dropped from 7 5 m above the floor of lift find distance travelled by the coin in ground frame before it strikes the floor A 5 m upward B 10 m downward C 10 m upward D 5 m downward

14 A block of mass 2 kg moves such that the V of velocity variation with position position is as represented in the graph The power delivered to the particle at x 2m will be v m s millest dy 2 dx a ydi 16 3 N 1 Aakash Ed 0 0 8 W 3 4 W 2 R R 1 4 2 3R 36 3 4 2 32 W 4 16 W 3R F V P ma v x m a large number of

Statement I Two particles moving in the same direction do not lose all their energy in a completely inelastic collision Statement II Principle of conservation of momentum holds true for all kinds of collisions

5 A long wire carries a steady current It is bent into a circle of one turn and magnetic field at the centre of coil is B It is then bent into a circular loop of n turns The magnetic field at the centre of coil for same current is 1 nB 3 2nB 2 n B 4 2n B

A ball is made of a material of density p where Poil P Pwater with Poil and Pwater representing the densities of oil and water respectively The oil and water are immiscible If the above ball is in equilibrium in a mixture of this oil and water which of the following pictures represents its equilibrium position a c water oil water oil 2000 4444 Baldo Pippbi44444 AAAAAAAAAA CRAPBAAAAA b d oil water oil 000 1414 1444444 4444444444 444 infote 4 water

Figure shows cross section view of a infinite cylindrical wire with a cylinderical cavity current density is uniform jok as shown in figure Field inside cavity is uniform Field inside cavity is along a Field inside cavity is perpendicular to a Back 8 Mark for Review Next If an alartenn ic neniantar with watocit illl movia ndau start hafera entiring with payitvall 8 Clear Response A Q X

D A magnet of magnetic moment 507 Am is placed in a magnetic field B 0 51 31 T The torque acting on the magnet is 1 175 k Nm 2 150 k Nm 3 75 k Nm 4 25 37 k Nm

owing questions A flywheel is spinning about its axis of symmetry has weight W and it rotates with a constant angul speed w Moment of inertia of the flywheel about the axis of its spin axis of symmetry is I and th distance of the flywheel from the pivot is r 7 8 The rotation of flywheel axis about the pivot is called A gyration C dipping precession D none of these The torque due to weight of the flywheel when the flywheel is rotating about its axis ALOnly changes the magnitude of its angular momentum BOnly changes the direction of angular momentum C Changes both direction and magnitude of D none of these

29 A ray of light falls on a transparent sphere with centre at C as shown in figure The ray emerges from the sphere parallel to line AB The refractive index of the material of sphere is 1 2 6 3 12 20 A 60 C B 2 3

A particle moves in space such that its velocity and at certain point is given by acceleration V v 41 m s and a 61 2 6k m s The magnitude of component of acceleration in the direction of velocity known known as tangential acceleration is

7 A rod of length 1000 mm and coefficient of linear expansion a 104 C is placed symmetrically between two fixed supports separated by 1001 mm The Young s modulus of the rod is 10 N m If the temperature is increased by 20 C then the stress developed in the rod is 1000 mm 1001 mm 1 10 N m 3 10 N m 2 10 N m 4 10 N m

16 3 A child in danger of drowing in a river is being carried downstream by a current that flows uniformly at a speed of m sec The child is 600m from shore and 800m downstream of a helipad when the rescue helicopter sets out and the helicopter follows the same direction throughout the motion If the helicopter 80 proceeds at its maximum speed of m sec 3 with respect to air and air is blowing with velocity of 4m sec perpendicular to river flow velocity as shown then the time in sec taken by helicopter to reach the child Wind 4m s

In shown system strings and pulley are frictionless and massless Block A is moving downward with velocity of 7m s which is increasing at a rate of 2 m s while block C is moving upward with a velocity of 9 m s which is decreasing at a rate of 3 m s The block B is moving downward with velocity of VB m s which is decreasing at a rate of ag m s Find the value of v l el 99

30 Light is incident normally on face AB of a prism as shown in figure A liquid of refractive index u is placed on face AC of the prism the prism is made of glass of refractive index The limit of 1 for which total internal reflection takes place on face AC is A 3 4 3 3 60 Liquid 90 B 30 3 2 2 4 2 C 3 3 4 7 3 4

x An inclined plane is bent in such a way that the vertical cross section is given by y where y is in vertical and x in horizontal direction If the upper surface of this curved plane is rough with coefficient of friction 0 5 the 4 cm maximum height in cm at which a stationary block will not slip downward is orrect Answer 25 00 swer 8 ect

An object is placed at a distance of f 2 from a conve lens of focal length f The image will be 1 At one of the foci virtual and double of its size 2 At 3f 2 real and inverted 3 At 2f virtual and erect 4 At f real and inverted

A rigid rectangular mesh measuring 0 300 m by 0 400 m carries a current of 3 70 A as shown A uniform external magnetic field of magnitude 1 20 T occurs in the negative x direction Segment CD is in the x z plane and makes an angle of 32 with the z axis as shown The external field magnetic flux through the mesh corresponds to a 0 110 Wb b 0 0920 Wb c 0 150 Wb d 0 120 Wb e 0 0760 Wb 3 7 AT 0 30 m B 32 Y KZ 0 40 m B 1 2T

8 In the network shown points A B and C have potential of 70 V zero and 10 V respectively Bov 70 V A www 100 2002 1 3 2 1 2 1 2 3 30 2 10 V The ratio of current in the section AD DB and DC are

Two blocks A and Beach of mass kg are connected by a massless inextensible string and kept on horizontal surface Coefficient of friction between block and surface is shown in figure A force where k 1 N s and this time in second applied on A Then g 10 m s F kt B 14 0 2 44 0 2 A 14 0 2 H 0 4 mum work done by friction force on block B is zero in time interval t 0 to t 3s work done by friction force on block A is zero in time interval t 0 to t 3s work done by tension on Bis also zero in time interval t 0 to t 3s speed of blocks at t 10s is 27 5 m s

Three short dipoles each of dipole moment of magnitude p are placed on a circle of radius Ras shown The magnitude of electric field intensity at centre will be 1 4kp kp 120 120 120 2 2kp

5 A charged particle q is shot from a large distance with speed v towards a fixed charged particle Q It approaches Q upto a closest distance r and then returns If velocity of q is halved then the closest distance of approach would be 9 1 2 2 3 2 2r 4 4r

lissipated in the 3 k and 20 k resistors and c the power supplied by the current source 3 KQ 21 1kQ 10 mA Figure 2 45 For Practice Prob 2 13 www 5 KQ 22 20 KQ Answer a 15 V 20 V b 75 mW 20 mW c 200 mW

QUESTION NO 7 INSTRUCTION Question given below has four answer options out of which ONLY ONE is correct Choose the area For CORRECT answer you will be awarded 4 Marks and for WRONG answer there is a negative marking question unattempted In the given figure possible direction of magnetic field for which net force on charge particle is zero q m V 1 along ve z axis 2 along ve z axis 3 along ve y axis 4 along ve y axis