Physics Questions

3 3 4 4 39 A light has amplitude A after passing through the polariser Angle between analyser and polariser being 60 Light transmitted by analyser has amplitude 1 A 2 3 3A 2 2 1 2 4 A 2

Charges 3Q Q are fixed as shown in diagram Then which of the following graph correctly represent the variation of electric field intensity along the line joining the two charges A B C D 3Q 3Q 3Q 3Q 3Q Q Q

5 Sound travels at a speed of 1450 ms through water A submarine detects object around it by sending sound waves and detecting echo reflected sound heard afte 4 seconds Then the object must be at distance of 1 1 450 km 2 2 900 km 3 4 350 km 4 5 800 km Ad 1450 2 M 2900km

6 A uniformly charged dielectric sphere of radius R carries a charge Q distributed throughout its volume Find the potential difference between its surface and a point at a distance R 2 from the center D A Q 8 ER B 16 EOR C 3Q 167 R 3Q 32 ER

Aakash Rank Booster Test Series for NEET 2020 43 The activity of a sample of a radioactive material is A at time t and A at time t t t If its mean life is T then 1 A t A t 3 A A e t t T 2 A A 1 t 4 A A e t t T

Find the time taken by block to reach bottom most point H 0 2 1 0 92 s 2 t t 2 3 2 9 8 2s a 9 8 a 0 2 2 0 2 4 9 1 79 3 1 2 2 E 200X 30 2 1 13 s 9 8 3 2 1 kg 5mC 1g sin30 REX 1m 3 2 1 s IN 1g cos30 LO 5 INST

R in a uniform magnetic field B a wire in shape of a semic rcle of radius r rotates about the diameter of the circle with angular velocity as shown in the f gure If the total resistance of the loop is R then the mean power generated per period of revolution is 1 3 2Br TR X X X X X X B 6 r4 8R X X X Xx X X X X X X X X X X X X X X X X 2 4 X X X X X X B w r 8R B r 2R

In YDSE d 1mm 6000 and D 1m The minimum distance between two points on screen having 75 intensity of the maximum intensity will be 1 0 50 mm 3 0 30 mm 2 0 40 mm 4 0 20 mm

38 Consider two circuits 7 hp XE L i A in which N identical bulbs are connected in series across a battery of emf E ii B in which N bulbs identical to those in A are connected in parallel across similar battery of emf E PA Power dissipating in each bulb in A PB Power dissipating in each bulb in B PAT Total power delivered by battery in circuit A PBT Total power delivered by battery in circuit B Choose the correct option PA N PBT PBT N PA 1 2 3 4 PBT N PAT PB N PA PA Ex hr 2 hR Ca Ehr

A block placed on x y plane at origin and is pulled by two forces F F where F is towards 3 4 m and F towards 4 3 m F is of magnitude 9 N and F is of magnitude 12 N O F can be expressed as 31 41 N IN F2 can be expressed as 12 41 31 L N 5 F F can be expressed as 15Ni component of F F 2 along y axis is zero 1

A block of mass m is suspended separately by two cifferent springs and is having time periods T and T2 respectively If same mass is connected to series combination of both springs then its time period is 2 T T2 4 T2 T 1 T T T T 2 T T 34

1 To 1 1 3 Ao Bo ABY 000 1 0 0 0 1 1 ABY 000 01 1 1 0 1 1 1 1 Diode 1 K Diode 2 2 4 Q 5 V ABY 0 0 0 1 1 1 0 0 1 1 ABY 0 0 1 1 1 0 0 1 1 0

Two particles A and B are connected by a rigid rod AB The rod slides along perpendicular rails as shown here The velocity of A to the left is 10 m s What is the velocity of B when angle a 60 a 10 m s c 5 8 m s b 9 8 m s d 17 3 m s 1998

Find the current through the 502 resistor if the voltage drop across 192 resistor is 3 V A IA B 1 33 A C 1 67 A D 2A 192 www 592 wwwww wwww 1002 2012

Width of a slab is 6 cm whose If its 2 rear surface is silvered and object is placed at a distance 28 cm from the front face Calculate the final position of the image from the silvered surface 2 10 3 60 1 30 4 45

When unpolarised light beam is incident from air onto glass n 1 5 at the polarising angle 1 Reflected beam is polarised 100 percent refracted beams are 2 Reflected and partially polarised 3 The reason for 1 is that almost all the light is reflected 4 All of the above

2 In the given circuit current I is independent of value of resistance Rs Then which of the condition must be satisfied A R R4 C R3R6 R R3 R R4 B R R3 R6 R R4 D R R3 R6 R R R4 R www R R wwww R R ww R

marks A plank inclined at an angle of a to the horizontal lies on two supports A and B figure over which it can slip without friction under the action of its own weight Mg With what acceleration and in what direction should a me mass m move along the plank so that it should not slip the man should move down the plank the acceleration of the man should be g sin a the acceleration of the man should be g sin a the man should move up the plank 1 1 B Save

5 15 The acceleration due to earth s gravity on a point particle at a height h above the surface of the earth is denoted by g h and at a depth d below the surface of the earth is denoted by g d Consider the earth to be a sphere of radius R with uniform mass density Which of the following correctly represents the ratio g d g d X 1 X 2 3 4 p b p 6 p 6 p 6 p 6 p 6 1 00 0 75 0 50 0 25 0 00 0 00 1 25 1 00 0 75 0 50 0 25 p 6 p 6 1 25 1 00 0 75 0 00 0 00 0 25 0 50 0 75 1 00 d R 0 50 0 25 0 00 0 00 1 25 1 00 0 75 0 50 0 25 0 25 0 00 0 50 0 75 1 00 1 25 d R 0 25 0 50 0 75 1 00 d R 0 00 0 25 0 50 d R 0 75 1 00

Cord is wrapped around a wheel in vertical plane and it can rotate about horizontal axis At end of string a block of weight mg is attached System is released from rest Find square angular frequency when block descends by height h 3 1 2mgh I MR mg mg T ma TR la a Ra mg a V R Ia R ma mg m I 2 R 2mgh m I R OR 2 mgh I 2mR 2mgh I 2mR 4 mgh I MR JUTE Jiable

Test 4 Code A 38 A capacitor of capacitance C is connected to a V volt potential Battery is then disconnected and inductor of inductance L is connected across the capacitor so that LC oscillations are set up The maximum current in the coil is C 1 3 V 1 3 4 39 The inductance of a closed packed coil of 400 turns is 8 mH A current of 5 mA is passed through it The magnetic flux per turn is Hg Permeability of free space 1 2 3 4x Ho Wb 1 3x 2L Ho Wb 4 0 4 Wb 40 A coil having n turns and resistance R is connected with a galvanometer of resistance 4R The combination is moved in time t such that magnetic flux per turn changes to flux 2 per turn The average induced current in the circuit is 5Rnt n 0 0 5Rt Rnt n Rt 2 2 v C 2VZ w dxxx 2x 4 41 A massless square loop of side carrying current i is suspended from a pulley as shown in the arrangement Lower edge of the loop is in transverse magnetic field B The minimum current i required in the loop to just move the block of mass m up the inclined plane is 2C Wb 3 42 1 2 3 4 Aakash Rank Booster Test Series for NEET 2020 mg sine mg cos BI 2 mg sine mg cose 2B 2mg sine 2 mg cose BI A conducting loop is placed in a magnetic field of strength B perpendicular to its plane Radius of loop is r current in the loop is i and linear mass density of loop is m Speed of any transverse wave in the loop will be 3 mg sine mg cos BI Bir m 2Bir m 2mv qE 3 43 A particle of charge q and mass m starts moving from origin under the action of an electric field Ei and B B with velocity v v The time after which its speed becomes 2v is 28 9 mvo 38 9 mvo 2 3 mv qE Bir 2m 4 2 Bir m 44 A conducting circular loop of radius r carries a constant current i It is placed in uniform magnetic field B such that B is perpendicular to plane of the loop Find the magnetic force acting on the loop 1 irB 2 2rriB 4 TriB 3 Zero 45 If current is passed in a spring then it 1 Gets compressed 2 Gets expanded 3 Oscillates 4 Remains unchanged

A point object O is placed in front of a gla u 3 2 rod having spherical end of radius c curvature 30 cm The image would be forme at 0 Air Glass 15cm 30 cm 1 30 cm left of surface 2 Infinity 3 1 cm to the right of surface 4 18 cm to the left of surface

Q62 Three resistors each of 2 ohm are connected together in a triangular shape The resistance between any two vertices will be 1 4 3 ohm 2 3 4 ohm 3 3 ohm 4 6 ohm 1 85 From NCERT PMT 1983 2 3 4

Q61 The reading of the ammeter as per figure shown is 292 1 A 2 A 3 A 4 2 A 1 252 ww 2V H 252 ww 252 www A 2 72 From NCERT 3 4

Negative Marks 1 In all other cases A swimmer crosses a river of width d flowing at velocity v While swimming he keeps himself always at an angle of 120 with the river flow and on reaching the other end he finds a drift of d 2 in the direction of flow of river The speed of the swimmer with respect to the still water is O 2 3 v 2 2 3 v O4 2 3 v O 2 3 v

A radioactive sample at any instant has its disintegration rate 5000 disintegrations per minute After 5 minutes the rate is 1250 disintegrations per minute Then the decay constant per minute is 1 0 8 En 2 2 0 4 n 2 3 0 2 n 2 4 0 1 En 2

Q63 There are n similar conductors each of resistance R The resultant resistance comes out to be x when connected in parallel If they are connected in series the resistance comes out to be 1 x n 2 n x 3 x n 4 nx 1 81 From NCERT PMT 2004 2 3 4

Q7 The equivalent resistance between points A and B in the circuit shown in the figure is 1 6R 2 4R 3 2R 4 R R R R 82 From NCERT R R R B 4

Q On a two lane road car A is travelling with a speed of 36 km h Two cars B and C approach car A in opposite directions with a speed of 54 km h 1 each At a certain instant when the distance AB is equal to AC both being 1 km B decides to overtake A before C does What minimum acceleration of car B is required to avoid an accident NCERT 1 m s

A smooth insulating ring of radius R with a bead of mass m and charge q is placed horizontally and in a uniform magnetic field of strength Bo and perpendicular to the ring plane Starting from t 0 the magnetic field is changed to B t Bo at where a is a positive constant t is time Neglect gravity The velocity of bead as function of time t qR E at X to X R Ring B X X X m q X Bead

Q65 A current of 2 A flows in a system of conductors as shown The potential difference VA VB will be 2A D 252 352 1 2 V 2 1 V 3 1 V 4 2 V B 30 292 www C 2 2A 292 352 ww 1 Subtopic Kirchoff s Voltage Law 3 A B 352 202 4

When a centimeter thick surface is illuminated with light of wavelength A stopping potential is V when the same surface is illuminated by light of wavelength 2A stopping potential is 3 Threshold wavelength for metallic surface is

Two coherent point sources S and S are separated by a small distance d as shown The fringes obtained on the screen will be 1 points vous d S S D Screen 2 straight lines

A small pencil of length 10 cm is k along the axis of a concave mirror of rad of curvature 40 cm with its tip touching mirror The size of pencil s image wo appears to be 1 5 cm 2 10 cm 3 20 cm 4 infinite loun dar

A block of mass 10 kg is placed on a rough inclined plane of nclination 370 tan 37 3 4 The coefficient of friction between block and surface is 0 4 A horizontal force F 50 N is applied on the block then g 10 m s F TITI 370 10kg u 0 4 acceleration of block is zero acceleration of block is 2 4 m s along the inclined plan frictional force between block and surface is 44 N frictional force between block and surface is 20 N

A man standing midway between two cliffs claps his hand and starts hearing a series of echoes of interval of 1 s The speed of sound in air is 340 m s the distance between the cliffs is 340 m 680 m 1020 m 170 m

Q2 If the voltage across a bulb decreases by 1 then the percentage change in its power output is 1 1 2 4 3 2 4 5 2 1 3 Subtopic Heating Effects of Current 0 4

A bird is flying towards north with a velcoity 40 km hr and a train is moving with velocity 40 km h towards east What is the velocity of the bird noted by a man in the train 33 40 km hr fafir 40 km hr Griffe au fondal frente fa 1 40 2 km hr north east 3 40 2 km hr north west 2 40 2 km hr south east 4 40 2 km hr south west

is rotating about a vertical axis in the plane such that the angular velocity of the particle about the axis is constant and is equal to 1 rad s Distance of the S A particle horizontal particle from axis is given by R R t where t stands for time The speed of the particle as a function of time is a B 1 c B B B 2 b R Bt d B R Ro

Three particles A B and C situated at vertices of an equilateral triangle all moving with same constant speed such that A always move towards B B always towards C and C always towards A Initial seperation between each of the particle is a O is the centroid of the triangle Distance covered by particle A when it completes one revolution around O is Burm y Hhalg fayu yull a end up Rea laa Aud uld u SA Y r Ja f AB B a Car CA HAG D H GH GU HEY ARCH OR H Y SU AERI I T GR SIN DINK JO yg huh 0 h uka Ych adche of a A 2a 1 e 2 37 2a 2 3 u a u B C a 1 e 2a 3

5 A particle moves along X axis from x 0 to x 1 m under the influence of a force given by F 3x 2x 10 Work done in the process is 1 4 J 2 4 J 3 8 J

Light of wavelength 6000 is incident on a thin glass plate such that angle of refraction into the plate of 60 If the smallest thickness of plate which makes it appear dark by the reflection is 4 x 107 m What is the refractive index of glass plate 1 5 3 2 3 2 3 PAN 413 4 2

Two resistances are joined in parallel whose resultant is ohm One of the resistance wire is broken and the effective resistance becomes 20 Then the resistance in ohm of the wire that got broken was 1 3 5 2 2 3 6 5 4 3 1 2 3 4

0 2 0 1 1 2 M 3 4 If in the system shown the initial acceleration of wedge of mass 5M is then value of x is pulley are 17 ideal and the chords are inextensible and there is no frictional any where uft zuf T Agru 5M GHH x 1 far gngef v zeeft at the adu bufera 1 17 5M t 2M Initially system is in equilibrium such that extention in each spring is same and spring constant of each 10n spring is k 100 N m Acceleration of block just after 1st and 3rd spring are burnt simultaneously is

1 Three 60 W 120 V light bulbs are connected across a 120 V supply If resistance of bulb does not change with temperature then find out power delivered to bulb A 120 V 1 20 W 3 80 W A BIO Cil 2 W 40 3 4 80 W

A sonometer wire of length is in resonance with a frequency 250 Hz If th length of wire is increased to then 2 beats per second are heard The ratio o lengths of wire will be 1 2 A B 124 125 C 2 1

In a hydrogen discharge tube it is observed that through a given cross section 3 13 x 1015 electrons are moving from right to left and 3 12 x 1015 protons are moving from left to right per sec What is the electric current in the discharge tube and what is its direction 1 1 mA towards the right 2 1 mA towards left 3 2 mA towards left 4 2 mA towards the right 1 2 3 4

Q55 A resistance R is stretched to four times its length Its new resistance will be 1 4 R 2 64 R 3 R 4 4 16 R 1 2 3 4

9 The three resistances of equal value are arranged in different combinations shown below The current entering from the left is same in all cases Arrange them in increasing order of power dissipation www www wwwwwwwwwwww III A III II IV I C I IV III ll www II www IV B II III IV I D 1 III II IV

Consider the following nuclear reactions and select the correct statements from the options that follow Reaction 1 n p e Reaction II p n e v A Free neutron has higher mass than proton therefore reaction I is possible B Free proton has less mass than neutron therefore reaction II is not possible for the free proton C Inside a nucleus both decays reaction I and II are possible D Inside a nucleus reaction is not possible but reaction II is possible