Basic Physics Questions and Answers

4 Assertion In parallel LCR circuit anti resonance can take place Reason Anti resonance takes place if inductive and capacitative reactances are equal and opposite a

15 Consider a monochromatic linear source of light which is placed at a distance of r from a very small metal plate Due to photoelectric effect electrons are ejected at rate N per second and it is found that maximum kinetic energy of photoelectron is K If source is brought closer to a the rate of emission and the r distance maximum kinetic energy of of photoelectron become nearly 1 F 3K 3 3N K 3 2 3N 3K 4 3N K

The magnetic field strength due to a short bar magnet on its axial line at a distance y is found to be B Find the magnetic field strength at the same distance on the equatorial line A B C B 2B B 2

Q69 A cell of negligible resistance and e m f 2 volts is connected to a series combination of 2 3 and 5 2 The potential difference in volts between the terminals of 3 resistance will be 1 0 6 V 2 2 3 V 3 3 V 4 6 V 84 From NCERT PMT 1976 1 2 Subtopic Grouping of Cells 3 4

A bar magnet is lying in equilibrium inside a uniform magnetic field B If W be the work done to rotate it through an angle 0 then the torque required to hold it in that position is A W cot B W tan C W cote D W tan 0 2 2

Q66 Referring to the figure below the effective resistance of the network is r ww 1 2r 2 4r 3 10r 4 5r 2 r www r r 92 From NCERT www

View In English Diagram shows symmetrically placed rectangular insulators with uniformly charged distributions of equal magnitude At th origin the net field Enet is aligned with the negative x axis aligned with the negative y axis aligned with the positive y axis aligned with the positive x axis YA X

An electron mass m with an initial velocity v v i v 0 is in an electric field E Ei Eo constant 0 It s de Broglie wavelength at time t is given by a 1 c 20 No eEot mvo 0 b 21 d t eEot mvo

variation of mobility u of electrons with applied electric field E in a metallic conductor HA 1 2 3 HA E E E

The drift velocity of the electrons in a current carrying metallic conductor is of the order of 1 10 m s 2 108 m s 3 10 m s 4 10 m s 1 2 3 4

The activity of a radioactive sample is measured as 9750 counts per minute at t 0 and as 975 counts per minute at t 5 minutes The decay constant is approximately 1 0 230 per minute 2 0 461 per minute 3 0 691 per minute 4 0 922 per minuta

25 Total uniform charge on a sphere of radius 2 cm 10 C The maximum electric field due to the spher is Nendation mited 1 2 25 N C 3 491 N C 2 225 MN C 4 600 mN C

A projectile is thrown horizontally from top of a tower of height 20 m with a velocity 10 m sec It strikes the smooth ground whose co efficient of restitution 0 5 g 10 m s2 neglect friction The time elapsed in seconds after projection when it strikes the ground 1st time will be 4 sec The time elapsed in seconds after projection when it strikes the ground 1st time will be 2 sec The time elapsed in seconds after projection when it strikes the ground 2nd time will be 3 sec The time elapsed in seconds after projection when it strikes the ground 2nd time will be 4 sec

of a rent ual 36 If a current flows in an 2 AC circuit across which an AC potential of V Vosinot has been applied then the average power consumption P in the circuit will be 1 2 2 Volo Volo 2 Volo lo sin wot

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 Ho Permeability of free space 1 3 1 4T 1 3T Ho Wb Ho Wb 2 1 27 No Wb 2T 4 0 4 Wb

A particle of mass m is taken with a constant speed v along the elliptical orbit as shown in figure semi major axis length a and semi minor axis length b 0 b a 0 0 b A The centripetal acceleration of particle at 0 b is B The tangential acceleration of particle at 0 b is zero va C The centripetal acceleration of particle at a 0 is b D The tangential acceleration of particle at a 0 is b a 0

An object starts from rest from point P and comes to rest at point Q on same straight line It moves the first part of the distance with an acceleration 1 m s and for the remaining with retardation 2 m s2 If time taken to complete the journey is 2 s then find the value of distance PQ O O O 7 43 3 E 6 m

When light of wavelength is incident on a metal surface stopping potential is found to be x When light of wavelength n is incident on the same metal surface stopping potential is found to be Find the threshold X n l wavelength of the metal 1 n 3 n 2 n 4 n

D D A ring of thin wire with active resistance R and inductance L rotates with constant angular velocity in the external uniform magnetic field perpendicular to the rotation axis In this process the flux corregnetic induction of external field across the ring varies with time as 6 40 cos at Pick the A B C For ferromagnetic Earth has a magnetic field very much geographic south pole to geographic north pole sin ot Power developed in the circuit due to rotation is given by L R The mean mechanical power developed by external forces to maintain rotation is equal to 1 w R P 2 R w L The mean power developed in the circuit is equal to P el cos where tan 2 OL R and lo is peak current The mean mechanical power developed by external forces to maintain rotation is equal ER where lo is peak current

In a coil of self inductance 20 mH the current varies with time t as shown in the figure 1 A LO 5 t ms 50 The magnitude of change in flux the coil from time t 0 to t 50 ms is 1 Wb

An object is launched from a cliff 20 m above the ground at an angle of 30 above the horizontal with an initial speed of 30 m s How far does the object travel before landing on the ground in metre 1 20 2 20 3 3 60 4 60 3

Figure shows three identical particles connected to massless rods forming an equilateral triangle System is spun and projected under gravity velocity of projection is in plane of figure Acceleration of centre of mass of assembly is g Centre of mass of assembly moves along a parabolic trajectory Each particle follows a parabolic trajectory Rods have no tension m m m

5 A particle moving in a straight line along points P Q R has an instantaneous velocity of 10 m s at a point Q The point P is 2 seconds before Q and point R is 2 seconds after point Q The particle has an acceleration of 2 m s2 Find the distance in meters between P and R

Find minimum force required to applied to the trolley of mass 9m so that blocks of masses 4m and m remain stationary with respect to the trolley Ground is smooth Coefficient of friction between each block and trolley is 0 2 A mg 3 2mg 3 B C mg D 4mg 3 Smooth Am 9m m

shape of square is placed in a variable magnetic field which varies at the rate of dB as shown in figure The magnitude of emf dt between points a and d along path abcd will be 1 L2 dB 2 dt 2 L2 dB dt 3 2 L dB dt 4 3 L2 dB 2 dt A d dt 34 35 36

32 In the following circuit diagram the value of i i is 222 www ing 20 V 1 2 A 3 8 A 29 www www 352 www 1092 422 2 4 A 4 6 A 10 V

corner of 73 Three identical charge Q are a equilateral triangle What should be the minimum velocity given to charged particle q placed at the centre of the triangle to escape from the electric field of identical charges m mass of charge particle at centre of Qq 3 7 2 4 Im 3 3Q9 37 2 1 Q 9 2 1 Q Qq 3 V 2 2re Im S 1 300 57 1 2

20 Two particles A and B are initially 40 m apart A is behind B Particle A is moving with uniform velocity of 10 m s towards B Particle B starts moving away from A with constant acceleration of 2 m s2 The time at which minimum distance between the two occurs is AK A 2 s C 5 s UA 10ms 40 m B B 4 s D 6 s UB 0 B 2 ms

11 In the circuit shown R 10 02 R 20 2 R 30 2 and R 20 02 Potential difference between b and d Vb Vd is b 1 1 V 2 2 V 3 3 V R R 15 V R R

ALONG WITH SOLUTION PLZ TELL ME WHAT APPROACH AN D WHICH METHOD SHOULD I TAKE IN WHAT WAY TO SOLV E FOLLOWING QUESTION AND ALL SUCH QUESTIONS OF T HIS CONCEPT a 30m long ladder weighing 200 kG leans on a frictionless wall with feet 1 m from wall base Find all reaction forces MY MAIN CONFUSION IS ABOUT TAKING EQUATING TORQU E ON BOTH SIDE PLZ ELABORATE THAT PART

If velocity of an electron in third energy level of a hydrogen like atom is v then velocity of electron in fifth energy level is Only one correct answer A B C 3v 5 9 25 25 V

iTutor All India Aakash Test Series for NEET 2021 21 Five point charges of charge Q each are placed at vertices of a regular hexagon as shown in the figure The direction of electric field at centre O is directed along A 1 OA 2 OF Q B Q F O C E3 Q D Q

28 Two non interacting inductors L 2 mH and L 5 mH are connected in parallel then respective ratio of 1 Flux is 1 1 2 Current is 5 4 3 Energy is 25 4 4 Energy is 4 25 L mm L mmm

The four arms of a Wheatstone bridge as shown in figure have resistances as indicated Calculate the current through conducting arm BD B 202 as EE F Ed 35 at Su 3 A 1002 A 60 D 492 10 V 2 48 91 C A 4 16 A

A toy cannon uses a spring to project a 5 40 g soft rubber ball The spring is originally compressed by 4 91 cm and has a force constant of 7 95 N m When the cannon is fired the ball moves 14 1 cm through the horizontal barrel of the cannon and the barrel exerts a constant friction force of 0 031 0 N on the ball a With what speed does the projectile leave the barrel of the cannon 1 389 m s b At what point does the ball have maximum speed cm from its original position c What is this maximum speed m s

11 Which of the following statements is true about magnetic field intensity a Magnetic field intensity is the number of lines of force crossing per unit volume b Magnetic field intensity is the number of lines of force crossing per unit area c Magnetic field intensity is the magnetic induction force acting on a unit magnetic pole d Magnetic field intensity is the magnetic moment per unit volum

27 Assuming the radius of the earth to be 6 4x106 What is the time period T and speed of satellite for equatorial orbit at 1 4 10 km above the surface of the earth 1 a 6831 s and 7174 ms c 6831 s and 2144 ms 1 b 34155 s and 3204 ms 1 d 2431 s and 3514 ms ravitational attraction between two points masses

Which of the following forces is not conservative Question Type Single Correct Type 1 2 3 4 F 31 41 F 3x1 4yj F 3y 4x1 F 3x i 4y j Your Answer Status correct

20 When a polythene is rubbed with wool it develops a charge 3 2 x 10 7 C The number of electrons transferred is 1 2 106 3 106 2 8 x 1016 4 2 1012

12 A particle has a rectilinear motion and the figure 12 gives its displacement as a function of time Which of the following statements is false with respect to the motion 1 Between 0 and A the velocity is positive and acceleration is negative 2 Between A and B the velocity and acceleration are positive 3 Between B and C the velocity is negative and acceleration is positive 4 Between C and D the acceleration is positive E SERIES JOINT 34 of farem a fa YA B 4 C an 1 APR 2 Virves 3 BC FICHE

4 L LT and T The inner diameter of hollow metal 6 cylinder is 20 0 5 mm and outer diameter is 210 1 mm then thickness of surface of cylinder with its error limits 1 1 0 6 mm 2 10 4 mm 3 0 5 0 3 mm 4 0 5 0 2 mm 4 L LT 3 T dung 20 0 5 mm 10 1 mm MIT NH CHI HAI 1 1 0 6 mm 2 1 0 4 mm 3 0 5 0 3 mm 4 0 5 0 2 mm

1 09 A raw egg and a hard boiled are made to spin on a table 09 with the same angular speed about the same axis The ratio of the time taken by the two to stop is 1 Equal to one 2 Less than one 3 More than one 4 Equal to two 271 10 A wheel of radius 20 cm has force applied to as shown in 10 20 cm fx d XY the figure The net torque is af f 8N B N AN 84 N m anticlockwise 2 1 8 N m clockwise 3 2 0 N m clockwise 4 5 4 N m clockwise PCP Sikar 6N 4t 9N Propulsive PTS G I co 80x8xle k 20540 091 1 2 1 1 1 3 unafun BN B30 1 5 4 N m HER 2 1 8 N m funer 3 2 0 N m ferment 4 5 4 N m fernand 2 4 6N AN IIT JEE NEET NTSE OLYMPIADS KVPY

3 A hollow metal sphere is filled with water and hung by a long thread A small hole is drilled at the bottom through which water slowly flows out Now the sphere is made to oscillate the period of oscillation of the pendulum A Remains constant B Continuously decreases C Continuously increases D First increases and then d

A particle B is moving in a vertical circle of radius a in anticlockwise direction with constant time period T Another particle A is undergoing S H M on its horizontal diameter with amplitude a and same time period T A is initially at its right extreme and B is at top most point as shown Sun is directly overhead Q 15 At what time does shadow of B first fall on A A 11 00 T B 8 B 7T 8

22 In the figure shown a coil of single turn is wound on a sphere of radius R and mass m The plane of the coil is parallel to the plane and lies in the equatorial plane of the sphere Current in the coil is i The value of B if the sphere is in equilibrium is a mg cos e T R mg TIR c B mg tan e mg sin e

average emt induced in 1 120 V 2 60 V 1 120 V 3 12 V 3 12 V 4 Zero 35 In a series LCR circuit current lags behind voltage then 35 su LCR T 1 C 2 JLC 1 4 w 0 VLC 6 Two identical equiconvex lens of focal length f and 3 11 1 2 refractive index Q 20x1 Fot O are in contact The space between 20 I two lenses are filled with certain liquid If the focal length I 36 1 VLC cu 3 VLC fafen T

In a YDSE let X and Y be the upper and lower slits A thin film of thickness t and refractive index is placed in front of X Let B fringe width The central maximum will shift Only one correct answer A B Downward Upward C Byt 1 i

The two spheres m 1 5 kg as seen in the figure are released from rest and gently nudged outward from the position 0 The spheres rotate in a vertical plane about the fixed centres of their attached gears where the centre distance is d 80 mm apart thus maintaining the same angel for both rods Determine the velocity v of each sphere as the rods passes the position 30 The spring of spring stiffens k 36 5 N m is unstretched when 0 and the masses of the two identical rods of length L 240 mm and the two gear wheels may be neglected Give your answer in m s do not include the units L m e k e 3

Accordig to VBT which of the following overlapping results type covalent bond in O molecule formation when Z axis is internuclear axis II 2p 2p IV 2p 2p 1 25 25 V 2p 2p A I III B IL V C II IV III 15 15

2 10 1 3 30 In the situation shown the potential difference across 30 the cell of smaller e m f is 1 2 V 3 Zero 12 V 192 www 10 V www i 192 222 2 4 V 4 6 V I fas 2 E IX LL 2 E 7 1 10 E 2i 12 28 22 12 2G 1 3 16