Basic Physics Questions and Answers

A particle is in an infinite square well potential with walls at x 0 and x L If the particle is in the state y x Asin 7 Where A is a constant Find the probability that the particle is in between x L 3 an x 2L 3 upto 2 decimal places

A pipe R can fill a tank in 45 minutes Two leakages P and Q empty the already filled tank in 90 minutes and 180 minutes respectively How long will it take to fill the tank if pipes P and Q are left open with pipe R O O O 3 hours 4 hours 5 hours 6 hours

3 11 A 250 g ball is launched with a speed of 35 m s at a 30 angle A strong headwind exerts a the wind constant horizontal drag force on the ball What is the magnitude of the drag force reduces the ball s travel distance by 20

The blocks MP 2 2 kg and MQ are connected by an inextensible rope passing over a frictionless pulley as illustrated in Figure 2 Initially the block MP is supported and therefore no block moves The coefficient of friction between the MP block and the horizontal surface is 0 40 When MP is released the blocks move with an acceleration of 0 50 m s2 Find the value of MQ MP

Problem 127 A cannon with bullets of total mass Mo is kept on a rough horizontal surface The coefficient of friction between the cannon and the surface is u If the cannon fires bullets with constant frequency with a relative velocity u find the velocity of the cannon when its mass with remaining bullets become M after time t Initially cannon was at rest Assume that the thrust force is greater than the limiting friction right from the beginning Mo cannon

12 Two fixed frictionless inclined planes making an angle 30 and 60 with the horizontal as shown in the figure Two blocks A and B are placed on the two planes What is the relative vertical acceleration of A with respect to B A B 60 1 4 9 m s in vertical direction 2 4 9 m s in horizontal direction 3 9 8 m s2 in vertical direction 4 Zero 30

3 If any how speed of light in vacuum becomes 1 5 times its initial speed then new value of light year in kilometers is 1 1 11 x 10 3 km 3 1 31 x 1013 km 4 1 41 x 1013 km 2 1 21 x 10 3 km

In the figure shown AB is a light ray incident on the face PS of a glass slab at an angle i 0 Given face PQ is silvered then the emergent ray D deviates by an angle C P A 20 Oc a 9

How much water overflows when a Pyrex vessel filled to the brim with 1 L of water at 25 C is heated to 194 F The coefficient of volume of expansion of Pyrex and water are 9 x 10 6 C and 2 1 x 10 1 C respectively

In the loops shown in Fig all curved sections are either semicircles or quarter circles All the loops carry same current The magnetic fields at the centres have magnitudes B B B and B Then D Q B b 1 B B B B 2 B B B B3 3 B4 B B B3 4 B B B3 B

23 A 1000 resistance and a capacitor of 1000 reactance are connected in series across a 220V source The peak value of the displacement current is 1 4A 2 11 2A 3 2 2A M

The e m f E of the battery is balanced by p d across 75 cm of a potentiometer wire For a standard cell of e m f 1 02 V the balancing length is 50 cm The value of E is A 0 68 V 1 53 V B D 1 24 V 1 08 V

39 A block of mass m is connected with a string which is wounded over a disc of mass 2m and radius R as shown in the figure If the system is released from rest then accelerations of the block will be 2m R 1 3 614 2 m 2 4 2g 3 3g 4

Assuming a javelin pole to be a point mass performing projectile motion and ignoring the height of sportsperson and air drag effects consider the given case Assume that a human is capable of throwing the javelin at a maximum range of 100 m Recently Neeraj Chopra in Tokyo Olympics 2020 threw it to a distance of 87 5 m If Neeraj threw the javelin at an angle of 45 with horizontal find the ratio of the speed of throw by Neeraj to the maximum possible speed of throw Take g 10 m s O 7 2 2 7 O 7 2 O 7

1 A perfectly reflecting mirror of mass m and exposed surface area A is exposed to electromagnetic radiation of intensity I on a rough horizontal surface with friction co efficient as shown 3 mgc IA The minimum value of pulling force required to exert 5 mg on mirror to move the mirror is The value of 2 1 4 3 2 3 where c is speed of light is m 1 B di 1 c d dt 2 B dl 3 8 di d 4 B di dt 2 If in a region there is a time varying electric field then which of the following Maxwell s equation will 7 be most suitable do dt H 501 4 143 2 4 The amplitude of electric field in an electromagnetic wave at a distance r from a point source of power P is taking efficiency 100 3 8 P 2rr E C P 8zr s C 2 A parallel plate capacitor consists of two circular plates each of radius 2 cm separated by distance of 5 x 1013 V s then value of displacement Telegram neetquestion 0 1 m If voltage across the plate is varying at P 4C current is P 4 2mr c EC In an electromagnetic wave the effective value of electric field is 100V m The intensity of the wave is 1 26 5 W m 3 46 7 W m 2 36 5 W m 4 76 5 W m 2 5 56 10 A 4 2 28 10 A x 7 60 A 3 5 56 A The nergy of a photon of EM radiation is of order of 1 Kev To which part of spectrum does it Je ng 1 y ray 2 x ray 4 U V rays 3 Infra red rays For an electromagnetic wave travelling along y axis the electric field component is known to be along 3 4k at an instant The direction of magnetic field at this instant is along 1 31 4k 3 41 3k 4 4i 3k A parallel plate capacitor consists of two circular plates of radius R 0 1m They are separated by a distance 1mm If rate of change of electric field between capacitor plates is the dE V 5x10 dt mxs between the plates is 1 13 9A the displacement current 2 0 39A

3 An em wave transports energy along y axis If at any instant magnetic field vector is along x axis the electric field vector at this instant is along 2 z axis 1 z axis 3 x axis 4 x axis 4 The electric field in an electromagnetic wave is given by F 100 cos 2 x 106 1 5x Vm 1 The average

circuit for Figure shows a potentiometer measuring the internal resistance r of a cell Y When the cell is an open circuit T is the balance point on the wire PQ The resistor R is used S A B C D Y P R 1 X Ir R T Q to make the galvanometer G more sensitive to produce a long balance length because G is sensitive galvanometer to protect the potentiometer wire

In an electromagnetic wave the effective value of electric field is 100V m The intensity of the wave is 1 26 5 W m 2 36 5 W m 4 76 5 W m 3 46 7 W m

3 WIN do 1 B d i 1 dt 2 B di H 3 B d Eg 4 If in a region there is a time varying electric field then which of the following Maxwell s equation will 7 be most suitable dog dt NICO 4 8 di H 1 d d 1 dt The amplitude of electric field in an electromagnetic 8

OR a What is double refraction Describe how Huygens explained it Describe the construction of half wave plate What is Malus law The principal planes of two Nicol prisms form an angle of 30 Prove that the intensity of the transmitted light diminished in the ratio of 3 2 if the angle between principal planes becomes 45

projectile motion and ignoring the height and air drag effects consider the given case Assume that a human is capable of throwing the javelin at a maximum range of 100 m Recently Neeraj Chopra in Tokyo Olympics 2020 threw it to a distance of 87 5 m If Neeraj threw the javelin at an angle of 45 O with horizontal find the ratio of the speed of throw by Neeraj to the maximum possible speed of throw Take g 10 m s 2 7 2 2

164 Two magnets each of magnetic moment M are placed so as to form cross at right angle to each other Magnetic moment of the system will be a 2M c M 2 b M d M VZ

1 Near and far points of a healthy human eye are 1 0 and 25 cm 2 0 and infinity 3 25 cm and 100 cm 4 25 cm and infinity 5 Mass of the earth is 81 times that of the moon If the distance between their centers is d then the point on the line joining their centers at which if any particle is placed it will not experience not

3 400 4 450 38 The natural frequency of the circuit shown in the figure is 1 3 eeeee fii L 2 2LC 2 2 31 C eeeee 2 2TVLC 2 LC 1 4 2 LC Telegram neet

3 H h pg cos 0 4 Hpg 15 Four point charges are placed in a straight line with magnitude and separation as shown in the diagram What should be the value of qo such that 10 C charge is in equilibrium 40cm 40 C 1 80 C 20cm 20cm 10 C 10 C 2 40 C 90

Jr Physics SMART Q 5 What is the contribution of S Chandra Sekhar to Physics AP Mar 17 16 15 13 June 15 TS Mar 19 15 June 15 A S Chandra Sekhar discovered the structure and evolution of stars He defined Chandra Sekhar limit which is used in the study of black holes 6 What is functio A In de and an

2 14 Figure shows the vertical cross section of a vessel filled with liquid of density p The normal thrust per unit area on the walls of the vessel at point P as shown will be 1 hpg 2 II 70 h H 2 H h pg

ternating Current 8 A resistance R draws power P when connected to an AC source If an inductance is now placed in series with the resistance such that the impedance of the circuit becomes Z the power drawn will be 1 P R Z 2 P RN

A body at rest is falling freely under gravity The distance travelled by the body in the first 3 s is equal to the distance travelled by the same body in the nth second What is the value of n O O 3 4 O 5

In Young s double slit experiment coherent light passing through two slits produces a pattern of dark and bright areas on distant screen If the wavelength of the light is increased how does the pattern change The spacing between bright areas remains the same but their position changes O The bright areas move closer together The bright areas move farther apart Any of the these can occur depending on the circumstances The spacing between bright areas remains the same but the colour changes

3 29 A transformer is used to light 140W 24V lamp from 240V a c mains The current in the mains cable is 0 7A The efficiency of transformer is 2 48 1 63 8 3 83 3 4 34

In a square field of side 20m there are two coconut trees A B at diagonally opposite corners of height 40 m and 20m respectively A bird comes flying ove the top of tree A along a straight line towards top of tree B with a constant speed of 10 3 m s Same time after the bird passes the top of tree A a water je 1 is fired vertically from the centre of the field which strikes the bird after 2 of firing Find the distance of bird from the top of taller tree when jet was fired

Q 13 A metal wire of length L area of cross section A and Young s modulus Y behaves as a spring of spring constant k given by 1 k YA L 2 k 2YA L od 30 3 k YA 2L 4 k YL A To

6 An electron moves along positive x axis with speed 10 ms Find its vertical displacement as it covers 10 cm along x axis if a vertical electric field of 910 Vm acts along ve y axis Ans 0 8 cm along ve y axis

A change in pressure is applied at a particular point in an enclosed fluid to every point of the fluid and the walls of the containing vessel Fill in the blank 1 Transmitted increasingly 2 Transmitted decreasingly 3 Transmitted undiminished 4 Transmitted randomly

in the L 43 The reading of voltmeter and ammeter in the am neetquestiollowing figure will respectively be X 40 1 OV and 2A 3 2V and 24 OL oooo X 40 90V www R 450 2 2A and OV 4 O and

72 If the rms velocity of molecules of a gas in a container is doubled then the pressure will 2 Also get doubled 4 Become one half 1 Become four times 3 Be same

Position of the object At infinity Beyond C At C Between C and F At F Between P and F Position of the image At the focus F Between F and C At C Beyond C At infinity Behind the mirror Size of the image Highly diminished point sized Diminished Same size Enlarged Highly enlarged Enlarged Nature ima Real and Real an Real a Real a Real Virtu

1 2mg 2 3mg 3 mg 4 zero 2 A train 1 moves from east to west and another train 2 moves from west to east on the equator with equal speeds relative to ground The ratio a1 az of their centripetal accelerations relati to centre of earth is Spa

54 A reference frame attached to the earth 1 is an inertial frame by definition 2 Cannot be an inertial frame because the earth is revolving around the sun 3 is an inertial frame because Newton s laws are applicable 4 is an inertial frame because the earth rotating about its own axis 55 What should be the acceleration of triangular block so that mass m just fly from its surface

50 The equation of a wave travelling on a string is y 4 sin wave is far 1 64 cm sec in x direction 3 32 cm sec in x direction 1 64 cm sec x 3 32 cm sec x fam y 4 sin NH 8t 8 x X 8t 100 If x and y are in cm then velocity o 2 32 cm sec in x direction 4 64 cm sec in x direction 2 32 cm sec x f 4 64 cm sec x f

2 210W 1 305W 3 Zero 4 121W 60 The direct current of 5 A is superimposed on an alternating current I 10 A sin oot flowing through a wire The effective value of the resulting current will be 1 15 2 A 2 5 3 A

13 In a constant volume gas thermometer the pressure of liquid at a temperature of 27 C being measured corresponds to 50 cm of mercury If the temperature increases by 20 K find the pressure O 53 33 cm 87 03 cm O 65 33 cm O97 03 cm

3 A astronomical telescope has objective and eyepiece of focal lengths 40 cm 4 cm respectively To view an object 200 cm away from the objective the lenses must be separated by a distance NEET 2016 a 46 0 cm c 54 0 cm b 50 0 cm d 37 3 cm

39 The ratio of KE of earth at perigee and apogee of orbit of earth during revolution around sun is chic gu geat at fa fa un m a 2 3 1 e 1 1 e 1 e 2 1 e 1 e 4 1 e

By applying a constant torque a wheel is turned 2 revolution in 8 sec The angular velocity of wheel after 10 sec from start rad sec fond d ec rad sec 1 4 TU 2 2 3 5 4 T 4 5100 10 sec TU

Electromagnetic Induction A wooden stick of length 31 is rotated about an end with constant angular velocity in a uniform magnetic field B perpendicular to the plane of motion If the upper of its length is coated with copper the potential difference across the coated length of the stick is 1 9Bol 2 2 4Bool 2

KX 3 Mass per unit length of a non uniform rod of length L is given by L and X is the distance from left end Distance of centre of mass from left end will be La FR 1 3L KX suf ychichts 3044112 JK AICHE FAX L fr ri L 2 3 where K is a positive constant 3K 4 K

irrors y zoom un Concave mirrors are commonly used in torches search lights vehicles headlights to get powerful parallel beams of light They fo

39 A ball suspended by a thread swings in a vertical plane so that its acceleration in the extreme position and lowest position are equal in magnitude The angle 8 of the deflection in extreme position will be 1 tan 2 3 tan NI 2 tan 2 4 2tan 2