Physics Questions

2 A is a thin walled sphere at rest made up of glass The radius of the sphere is Im and it is filled with a transparent liquid of refractive index S is the luminous source moving directly towards a plane vertical mirror M A fish in the liquid is moving towards S The eye of the fish and S and collinear perpendicular to mirror M At the instant shown S is 3m away from the center of the sphere fish observes that image of S due to reflection is moving with speed of 13m s If speed of the fish relative to the sphere is 10m s and 1 5 then find the speed of the source at that instant The system is placed in air Fish THE NARA GR A GROUP

50 A dipole consists of two particles one with charge 1 C and mass 1kg and the other with charge 1 C and mass 2kg separated by a distance of 3m For small oscillations about its equilibrium position the angular frequency when placed in a uniform electric field of 20kV m is A 0 1 rad s C 10 rad s B 1 1 rad s D 2 5 rad s

he radioactive isotope of hydrogen is H 2 H 3 H 4 H Solution In dinoflagellates cells are generally covered by a rigid coat theca or lorica of articulated and sculptured plates formed of cellulose because of which these protists are often known as armoured dinoflagellates Hence option c Albugo Saccharomyces is

10 In a compound microscope the lateral magnifications of objective lens is 5 and magnifying power of eyepiece is 2 then magnifying power for compound microscope for normal adjustment will be 1 2 5 2 10 4 5 3 2

A uniform thin circular disc of mass M and radius R lies in the X Y plane with its centre at the origin Find the moments of inertia tensor What are the values of the principal moments of inertia Find the principal SEA axes

Three separate segments of equal area A A2 and A3 are shown in the energy distribution curve of a blackbody radiation If n n and n3 are number of photons emitted per unit time corresponding to each area segment respectively then E OOOO A A N2 N1 N3 N3 N1 N n n Nz N3 N2 N1 A D

A particle initially at rest is moving on a straight line If s v F P and t denote displacement velocity force power and time respectively then Column I Column II D A P constant B F constant 1 C Foc 3 P 3 S Q xt R cs

3 2 4 2 5 85 A convex lens of focal length f and dispersive power is combined with a concave lens of focal length f2 and dispersive power 2 is such a way that an achromatic doublet of focal length 40 cm is obtained If respectively 1 3 40 3 40 3 per 20 20 00 02 2 3 1 then f and f2 in cm are 2 20 4 20 40 we we

6 The radius of a circular coil of 100 turns is 5 cm and it car ries a current of 10A What torque will act on the coil when its plane is kept at 30 with a uniform magnetic field of 0 039 N m 0 01 T

76 A small pin fixed on a table top is viewed from above from a distance of 50cm By what distance would the pin appear to be raised if it is viewed from the same point through a 15cm thick glass slab 3 held parallel to table R I of glass 1 15cm 3 5cm 2 10cm 4 35cm

d 20 cm The focal length of a simple convex lens used as a magnifier is 10 cm For the image to be formed at a distance of distinct vision D 25 cm the object must be placed away from the lens at a distance of MP PET 2008 a 0 5 cm c 7 20 cm b 7 14 cm d 16 16 cm

A bird can fly in the air at a constant speed 13 m s There is a wind of speed of 18 km hr blowing from the north The bird has to move in the east west direction What is its speed in m s with respect to the earth 1 5 2 12 3 13 4 18

If a collision takes place between A and B and the coefficient of restitution is c 0 5 what is the magnitude of the x and y components of the velocity of A after the impact in m s Motion is confined to the x y plane O a Vx 1 321 Vy 1 526 Ob Vx 1 294 Vy 1 532 OC VX 1 551 Vy 1 667 d VX 1 732 Vy 1 528 e VX 1 421 Vy 1 432 10 kg 45 A 12 kg A 3 m s 30 20

The displacement of particle is zero at t 0 and at t t it i x It starts moving in the x direction with velocity which varies as v k x where k is constant The velocity 1 varies with time 2 is independent to time 3 inversely proportional to time 4 inversely proportional to acceleration

3 An object is thrown up in the air At time t measured in seconds the height of the object is h t 50t 16t2 measured in feet Find the velocity of the object at the following times t 1 and t 3 Interpret the sign of the velocity in each case

An achromatic convergent lens of focal length 20 cm is made of two lenses in contact of materials having dispersive powers in the ratio of 1 2 and having focal lengths f and f respectively Which of the following is true 1 f 10 cm f 20 cm 2 f 20 cm f 10 cm 3 f 10 cm f 20 cm 4 f 20 cm fa 10 cm

A metal sphere is given charge Q as shown in the figure A point charge Q is placed at a distance 4R from the centre of the sph choose correct statement s ect Answer 4 Answer 1 is incorrect R Net electric field at point P is zero In absence of point charge field at O is non zero In presence of point charge field at P is towards metal sphere iv in presence of point charge field at O is zero 1 i iii iv are correct i ii are correct ii iii are correct iii iv are correct Metal sphere R 2R

kash Institute 3 For an astronomical telescope magnification produced in normal adjustment is 10 and length of telescope is 1 1m The magnification produced when image formed at least distance of distinct vision is 1 14 2 18

The volume flow rate of water flowing out of a tubewell 3t 4t 1 m sec What will be the volume of water flown out of the tubewell in the 3rd dv is given by Q sec if the volume flow rate is defined as Q dt 1 10 m 2 17 m 3 3 36 m 3 4 34 m 3

To get four images of an object placed symmetrically between two plane mirrors the angle between the mirrors must be 1 90 3 72 2 36 4 120

Two spheres P and Q of equal radii have densities p and p2 respectively The spheres are connecte by a massless string and placed in liquids L and L2 of densities 1 and 2 and viscosities and respectively They float in equilibrium with the sphere P in L and Q in L2 and the string being tau If sphere P alone in L has terminal velocity up and Q alone in L has terminal velocity vo then a b 41 as de r 71 12 4 L2 P Q

suppose two planets spherical in shape in radii R and 2R but mass M and 9M respectively have a centre to centre separation 8 R as shown in the figure A satellite of mass m is projected from the surface of the planet of mass M directly towards the centre of the second planet The minimum speed v required for the satellite to reach the surface of the second planet is then the value of a is a GM 7 R Given The two planets are fixed in their position MR 9M 2R

88 A ray is incident on face PQ at an angle of 45 The refracted ray undergoes reflection on face PR and retraces it s path The refractive index of the prism is 1 2 3 1 5 30 R 3 2 2 4 1 33

2 48 A diatomic ideal gas is used in a Carnot engine as the working substance If during the adiabatic expansion part of the cycle volume of the gas increases from V to 32 V the efficiency of the engine is 1 0 5 0 99 12 0 75 4 0 25

Q 19 Equipotential lines arising from a static charge distribution has been shown in a certain region of space a Draw the electric field lines starting from point A b If a charge is released at A will it move along the field line passing through A c How much work is done by the electric force if a charge moves from B to C Is the knowledge of path important in this calculation 50 V 40 V 30 V 20 V 10 V 0 60 V 70 V B C A 80 V 90 V

At STP a rod is hung from a frame as shown in figure leaving a small gap between the rod and floor The frame and rod system is heated uniformly upto 350 K Then 2 If 1 The rod will never touch the floor in any case then rod may touch the floor then rod may touch the floor a rod frame rod frame 3 If a a frame 4 None of the above Rod

A positive charged particle when moves from higher potential to lower potential O Its potential energy must increase Its kinetic energy must increase OIts potential energy may decrea

a photoelectric experiment the stopping potential V versus applied frequency v graph for three different metals A B C are as shown The metal with maximum threshold wavelength is V M A 3 C ABC 2 B 4 All have same values

3 A force of 0 1176 N acts horizontally for 5 s on a 50 g block kept on a floor What is the velocity attained by the block Coefficient of sliding friction between the block and the floor is 0 2 196 cm s 1

Which of the following is incorrect statement O Electric field is sometimes non conservative O Electric field due to a stationary charge is conservative O Electric field due to a varying magnetic field is non conservative O Electric field lines are always closed loops

A block of wood floats in freshwater with two third of its volume submerged In oil the block floats with one fourth of its volume submerged The density of oil is A 2666 7 kg m C B 5333 3 kg m 3 1333 3 kg m 3 D 3 Correct Answer 3333 3 kg m 3

The diagram shows the P V diagram of a cyclic process ABCA P Nm 2 10 6 2 THE N A Work done in process A Bis 0 036 J B Work done in process B Cis 0 024 J C Work done in process C Ais zero D Work done in cycle ABCA is 0 06 J 0 6 8 10 12 V litre GRO

Four vectors A B C D all have the same magnitude and lie in a plane The angle between adjacent vectors is 45 as shown Which of the following equation is are correct A A C 2 C A B B D B B D 2C 0 D A C 2 B A 45 45 45

As the switch S is closed at t 0 the ring B 1 is attracted towards A 2 is repelled by A 3 is initially repelled and then attracted 4 is initially attracted and then repelled

In Young s double slit experiment the slits are 2 mm apart and are illuminated by photons of two wavelengths 12000 A and 10000 A At what minimum distance from the common central bright fringe on the screen 2m from the slit will a bright fringe from one interference pattern coincide with a bright fringe from the other NEET 2013 1 6 mm 2 4 mm 3 3 mm 4 8 mm

Figure shows some of the electric field lines corresponding to an electric field The figure suggests that E electric field V potential O EA EB O VA VB B O EA EB O VA VB

Two objects of masses m and 4m are at rest at infinite separation They move towards each other under mutual gravitational attraction Then at a separation r which of the following is true A The total kinetic energy of the system is not zero B The force between them is not zero C The centre of mass of the system is at rest D All the above are true

One end of an ideal spring is fixed to a block of mass m and the other end is free The block is placed over a smooth horizontal floor Initially the spring is unstressed and the block is at rest Now the free end of spring is pulled to right with a constant horizontal velocity of magnitude v For this given spring b system match the statements given in column I with statements in column II 000000 77777 Column I A When the length of spring is maximum B When the length of spring is minimum C When the length of spring is equal to its natural length D When the net force on the block is zero Column II p the speed of block is v q the speed of block may be zero r the speed of block may be 2 v s the kinetic energy of block may be maximum

Five charges each q are placed at five corners of a regular pentagon Distance from corner to the centre of pentagon is r Then K O Potential at centre is 470 5kq O Electric field at centre is non zero O Potential at centre is zero O None of these

4 both 1 and 2 are possible 3 A convex lens made of a material of refractioneetque index 1 5 and having a focal length of 10 immersed in a liquid of refractive index 3 0 will behave as a 1 Converging lens of focal length 10 cm 2 Diverging lens of focal length 10 cm 10 3 Converging lens of focal length cm 4 Diverging lens of focal length 30 cm lens 48

A tank contains a transparent liquid of refractive index The bottom of the tank is a plane mirror as shown A person at P looks at an object O and its image in the mirror The distance between the object and its image in the mirror as perceived by the person is 1 2 d 3 2 d P 0 2 4 2d H d H

A glass clad fiber is made with the core glass of refractive index 1 6 and the cladding is doped to give a fractional index difference of 0 006 Calculate 1 the refractive index of the cladding ii the critical angle iii the numerical aperture and iv the acceptance angle Select the nearest answer in the options given by doing calculation up to the third decimal a i 1 590 ii 83 72 iii 0 176 and iv 10 14 b i 1 490 ii 93 72 iii 0 276 and iv 20 14 c i 1 690 ii 73 72 iii 0 176 and iv 15 14 d i 1 590 ii 83 72 iii 0 276 and iv 20 14

4 both 2 and 3 11 If velocity p acceleration q and density are taken as fundamental quantit Then the dimensional formula for kinetic energy k is 1 p82q3 2 p28a3 4 n 3 mage

Q2 NTA Test 02 Numerical A point object is moving with a speed v in front of an arrangement of two mirrors as shown in figure If the velocity y of image in mirror M wit respect to image in mirror M is n v sin find n mathong mathong matho M mathongo 14 hongo mathonge m mathongo mathongo mathonga mathongo 4 07 pm

C VC A N VAN VBN B R wwm R jX C jXca Rea R3 jX3 13a Find the magnitude of the delta current lab Ibic or Ica in A at the load Submit Answer Tries 0 3 13b Find the phase angle of the delta current lab in degree at the load Submit Answer Tries 0 3 13c Find the phase angle of the delta current Isc in degree at the load Ica Submit Answer Tries 0 3 13d Find the phase angle of the delta current Ica in degree at the load a lab jXab Rab Rbe jXbe Ibe www

The machine as shown has 2 rods of length 1 m connected by a pivot at the top The end of one rod is connected to the floor by a stationary pivot and the end of the other rod has a roller that rolls along the floor in a slot As the roller goes back and forth a 2kg weight moves up and down If the roller is moving towards right at a constant speed the weight moves up with a Jee Main 2017 A constant speed C increasing speed F 2 kg Timmy T Movable roller X Fixed pivot B decreasing speed 1th of that of the roller when the weight is 0 4 m above the ground

48 A tank contains a transparent liquid of refractive indexu The bottom of the tank is a plane mirror as shown A person at P looks at an object O and its image in the mirror The distance between the object and its image in the mirror as perceived by the person is 1 2 d 3 2 d

A small body is thrown at an angle to the horizontal with the initial velocity vo Neglecting the air drag find a the displacement of the body as a function of time r t b the mean velocity vector v averaged over the first t seconds and over the total time of motion

2 00 nF capacitor with an initial charge of 4 97 C is discharged through a 2 36 kn resistor a Calculate the current in the resistor 9 00 us after the resistor is connected across the terminals of the capacitor Let the positive direction of the current be define such that d mA d b What charge remains on the capacitor after 8 00 us HC c What is the magnitude of the maximum current in the resistor

A block of mass m is attached to a spring of force constant k Charge on the block is q A horizontal electric field E is acting in the direction as shown Block is released with the spring in unstretched position Mark incorrect statement k eeeee eeeee Smooth q m O Block will execute SHM Amplitude of oscillation is E O Time period of oscillation is 21 Block will oscillate but harmonicall m tmpt simple