Basic Physics Questions and Answers

A two dimensional spike type inlet is operating in the supercritical mode at a flight Mach number of 3 0 The local static pressure and temperature are 50 kPa and 260 K respectively The flow cross sectional area at the cowl inlet A is 0 1 m the cross sectional area at the location where the normal shock occurs in the diverging passage A3 A4 is 0 12 m See Figure 8 6 Calculate the mass flow rate and total pressure ratio Pol Po3 Neglect friction The spike half angle is 10 and the ratio of specific heats is y 1 4 M 1 2 3 Figure 8 6 Flow Regions within a Spike Diffuser Operating in the Supercritical Mode

Online Mock Test Series for NEET 2020 11 Suppose the gravitational force varies inversely as the nth power of distance Then time period of a planet in circular orbit of radius R around the sun will be proportional to 1 R2 3 R 2 R n 4 R2

30 A liquid is filled in a spherical container of radius R till a height h At this position the liquid surface at the edges are horizontal The contact angle is 1 0 sin R 2 cos R h R 4 sin R h

Raghu is running on a straight horizontal road on a rainy day with a speed 4 m s He observes that the rain is falling down vertically with a speed 3 m s The actual speed of raindrops is 1 3 m s 2 4 m s 3 5 m s 4 2 m s A stone of mass 4 kg is whirled in a horizontal

125 kJ 28 Two pendulums X and Y of length 1 44 m and 1 69 m are at their equilibrium positions in same phase initially After six complete oscillations of the pendulum Y the phase difference between X and Y will be 1 180 3 360 2 90 4 30

A body is projected vertically upwards from the surface of a planet of radius R with a velocity equal to half the escape velocity for that planet The maximum height attained by the body is A R S B R 4 C R 3 D R 2 A A

4 64 charged drops coalesce to form a bigger charged drop The potential of bigger drop will be n times that of smaller drops then n is 1 4 2 16 3 64 4 8 3 A motor vehicle moves such that the velocity is a 2

A wire in the shape of a square frame carrying current lo produces magnetic field Bo at its centre Same wire is remoulded in shape of a circular loop Magnetic moment of the loop is 16 3 3 B3T 64 313 B3 32 3 B 3

A stone of mass 4 kg is whirled in a horizontal circle by attaching it to a 169 m long string The string can withstand a maximum tension of 4N The maximum speed of revolution of the stone such that the string does not break is 1 10 m s 2 13 m s 3 16 m s 4 12 m s

Determine how much the average force acting on the eardrum of the human ear area S 66 mm is less than the pain threshold if the sound pressure is 145 4 Pa The sound frequency is 1 kHz The sound pressure corresponding to the pain threshold is considered equal to 200 Pa Please enter the units of measurements in your answer

connected across a uniform wire AB of length 100 cm The positive terminal of another battery of emf 4 V and internal resistance 10 is joined to the point A as shown in figure If galvanometer shows zero deflection then 6 V A www 4V 19 AC 50 cm AC AC 50 cm 100 cm 3 AC 20 cm B

0 0 20 0 71 Consider A 2 4 10 6 12 and evaluate the followings L2 4 10 6 5 a Find the basis for and the dimension of the row space of A b Find the basis for and the dimension of the column space of A Consider the col space of A is same as the row space of AT c Find the basis for and the dimension of the solution space of A d Find the basis for and the dimension of the left null space of A

27 identical cells each of 10 V and 3 Q are used in a circuit 3 cells are joined in series to form a line and 9 such lines are connected to an external resistance R If the value of Ris adjusted such that power P dissipated through it is maximum then P 900 W P 150 W P 225 W P 750 W

A In the arrangement shown in the figure there is a horizontal cylindrical uniform but time varying magnetic field increasing at a constant rate A charge particle having charge q and mass m is kept in equilibrium at the top of a spring of spring constant k in such a way that it is on the horizontal line passing through the centre of the magnetic field as shown in figure If the compression in the spring is x the constant rate of varying magnetic field is B C 21 3qR 21 qR 21 kr mg qR 51 kz mg kr mg eeee 2 k

Problem 5 34 Suppose that WGN n t with PSD o 1 is passed through a filter wi impulse response h t I 1 1 t to obtain the output y t n h t a Find and sketch the output power spectral density S f carefully labeling the axes b Specify the joint distribution of the three consecutive samples y 1 y 2 y 3 c Find the probability that y 1 2y 2 y 3 exceeds 10

Figure shows two line sources of sound S and S separated by a distance 4 m The two sources are in same phase at all times The sources emit same power arid their lengths are also same A detector moves along circle with center at S and radius 3m The wavelength of the sound is 1 m When it is at A the intensity of sound due to source S only is 1 B The intensity of sound at A due to S only is 1310 A B 3 The intensity of sound at B due to S only is 51p A 31 13 31g 5 B The intensity of sound at B due to S and S is 70 3 C C 910 13 910 25 81 D L D I C mo N 9

Two solid discs of radii r and 2r roll from the top of an inclined plane without slipping Then A the smaller disc will reach the horizontal level first B the bigger disc will reach the horizontal level first C the time difference of reaching of the discs at the horizontal level will depend on the inclination of the plane D both the discs will reach at the same time A You Marked

A block of mass m is connected to thre springs as shown in the figure The block displaced down slightly and left free it star oscillating Find the time period of oscillation neglecting gravity Given m kg n 1 0 60 k 4N m k 23 N m elle m elle k elle

In the figure given below if ammeter reading is 0 8 A and the current passing through 20 Q resistance is 0 3 A then the value of resistance Ris ter RT 0 3 A R www 20 92 www www 15 Q ich 0 8 A 20 A

1 In the arrangement shown in figur m m mg 2m and me and pulleys to be light the acceleration of block C is 1 3 3Mg 3M 4m 2Mg 3M 4m 2 4 Mg 3M 4m Mg 3m Ho A M Assume all surfaes to be smooth

In a large building there are 15 bulbs of 40 W 5 bulbs of 100 W 5 fans of 80 W and 1 heater of 1 kW The voltage of the electric mains is 220 V What will be the minimum capacity in amperes of the main fuse of the building

Two ideal gases are of same volume are under same temperature and pressure The ratio of their mean paths of molecules if their diameter are 1 A and 2 A is A 2 1 B 4 1 C 1 4

ressure is doubled P2 the gas is the

Find the value of parallel capacitance in mF needed to correct a load of 140 kVAR at 0 85 lagging pf to unity pf Assume that the load is supplied by a 110 V rms 60 Hz line

0 Figure shows a conductor of length l having a circular cross section The radius of cross section varies linearly from a to b The resistivity of the material is p Assuming that b a find the resistance of the conductor a 11 dx b

A block of mass m is connected to three springs as shown in the figure The block is displaced down slightly and left free it starts oscillating Find the time period of oscillations neglecting gravity Given m kg n 10 0 60 k 4N m k 23 N m Heeee k m oooo ell k oooo k

A long cylindrical region has a uniform charge density p A cylindrical cavity is formed in the region so that it is charge free The axis of the cylindrical cavity is at a distance I from the axis of the cylindrical region Electric field in the cavity is A C 280 En B D pl 480 2pl 0

A bird is flying with a speed of 40 km h in the north direction A train is moving with a speed of 40 km h in the west direction A passenger sitting in the train will see the bird moving with velocity 1 40 km h in N E direction 1 2 40 2 km h in N E direction 3 40 km h in N W direction 4 40 2 km h in N W direction

An insect at a distance 10 cm from a curved surface shown in figure is moving with a speed 2 mm s Fin speed of its image as seen by observer on other end 1 1 mm s 3 2 mm s f H 1 5 R 10 cm 0 2 3 mm s 4 4 mm s

R The size of air molecules on the moon is so small so scattering of sunlight does not take place 10 A If a concave mirror is kept in water its focal length decreases Focal length of concave mirror is independent of the refractive index of the medium used R 11 A pH of pure water is always 7 R Pure water contains equal concentration of hydronium ion and hydroxide ion

9 A long straight wire carrying a current of 200 A runs through a cubical box entering and leaving through holes in the centres of opposite faces as shown in Pig 4 19 Each side of the box is of 20 cm A D PQC Fig 4 19 Consider an element PQ of the wire 1 cm long at the centre of the box Calculate the magnetic field produced by this element at the points A B C and D The points A B and C are the centres of the faces of the cube and D is the midpoint of one edge Ans 20 x 10 6 T 20x10 6

A rod AB of length 2m moves in horizontal x y plane At any instant end a of the rod is at origin and has velocity v 21 vj The other end B at the same instant is moving with velocity V 31 6j The rod makes an angle of 30 with the x axis at this instant see figure A 3 1 y B zero 2 m The component of velocity of centre of mass in the direction perpendicular to the rod at the given 335 instant is 3 3 2 C 3 3 30 V 3i V 2i vyj X

Block A of weight 500 N and block B of weight 700 N are connected by rope pulley system as shown The largest weight C that cam be suspended without moving block A and B is W The coefficient of friction for all plane surfaces of contact is 0 3 The pulleys are ideal Find W 90 A 12 C A B B 22 C 9 G D 18

Two blocks of mass 1 kg each are connected through a light inextensible string as shown in figure The friction coefficient between each block and horizontal surface is 0 2 A time varying force given by F 20 N s xt is applied to block B as shown where t is time g 10 m s A 1 kg Fixed Column I 1 Att 1 s acceleration of block A is 1 2 At t 10 3 At t s tension in string in block B is 3 20 on block A is s friction force 4 Motion will start at time t is given by B 1 kg F 20 t Column II In SI unit P Zero Q R S 90 13 2 3

Protons are incident on a copper foil 12 m thick a What should the proton kinetic energy be in order that the distances of closet approach equal the nuclear radius 5 0 fm b If the proton energy were 7 5 MeV what is the impact parameter for scattering at 120 c What is the minimum distance between proton and nucleus for this case d What fraction of the protons is scattered beyond 120

1 A battery consists of a variable number n of identical cells having internal resistance r each which are connected in series The terminals of the battery are short circuited and the current I is measured Which of the graphs shows the correct relationship between I and n I c Find A n b n 100 2nd O O n to sulsort sted di mwede drowisa srly 70 d of Artwoll d I n AFET 2018 Asked by 2012502 aesl id Standard XII Stream NEET Aug 3 2021 at 2 30 PM Add your responses Type Text Type your answer here OR you can upload an attachment from the option below Attachment size should be 5MB or less Keep the format in jpg or png or pdf or doc or docx only 2

11 A pH of pure water is always 7 R 12 A R Pure water contains equal concentration of hydronium ion and hydroxide ion Gallium and caesium will melt if we keep them on our palm Gallium and caes um have very low melting points

For the circuit shown in the figure if capacitor C is initially uncharged then current in the circuit at t 0 is 5Q 20 V 502 O 4A O 6 A O SA 50 3 and 4 out of which c C

2WDg 2S The temperature of an ideal gas is increased from 27 C to 927 C The RMS speed of its molecules becomes 1 One fourth 3 Half 2 Four times 4 Twice

SolveLancer Test Consider three statement about the concave mirror i The focal length of mirror will change if mirror is placed in oil ii If incident ray is parallel to principal axis then reflected ray retraces the path ii The focal length of a mirror does not depends on its radius of curvature Pick suitable option SolveLancer Test a Only i is true b ii iii both true c All are false statements d Only ii is true

R Simple diffusion will meet the requirements of all the cells 14 A In multicellular organisms various body parts have specialised in the functions they perform R The uptake of food and oxygen will also be the function of specialised tissues Case Study Based Questione

An oil drop of radius 10m carries charge equal to that of three electrons If density of oil is 2 x 10 Kg m then electricfield required to keep the drop stationary is a 1 7 x 10 5 v m c 17 x 10 v m b 17 v m d 0 017 v m

The coercivity of a small magnet where the ferromagnet gets demagnetized is 3 x 10 A m 1 The current required to be passed in a solenoid of length 10 cm and number o turns 100 so that the magnet gets demagnetized when inside the solenoid is O 30 mA O 60 mA O 3 A 06 A

5 P V diagram of a cyclic process is given The process is performed on one mole of monoatomic gas Then find the efficiency in during the process ACB P 4Po Po A B 0 C

melting points 13 A Oxidising reducing reactions are some of the most common chemical means to break dov R Simple diffusion will meet the requirements of all the cells

A crank drive mechanism is illustrated below A uniform linkage BC of length L connects a flywheel of radius r rotating about fixed point A to a piston at C that slides back and forth in a hollow shaft A variable torque T is applied to the flywheel such that it rotates at a constant angular velocity Show that for one full rotation of the flywheel energy is conserved for the entire system consisting of flywheel linkage and piston assuming no friction Note that gravity g is acting downwards as shown Even though energy is conserved for the system why is it a good idea to make the components of the drive mechanism as light as possible with the exception of the flywheel Bo L 60 g

A solid conducting sphere having net charge Q and radius 3a contains a hollowed spherical region of radius 2 a A point charge Q is placed at a position a distance a from the common center of the spheres What is the magnitude of the electric field at the position r 4 a from the center of the spheres as marked in the figure by P A B C D kQ 16 a 3kQ 16 a kQ 8a B a P can t be determined due to uniform distribution non

Which of the following particles will have maximum radius of curvature of path when projected with same kinetic energy with velocity perpendicular to magnetic field O Electron O Proton OLit

An ideal monoatomic gas undergoes an expansion from state A to state B following a process which is shown in the indicator diagram If initially during the expansion the gas was absorbing heat and later on it was rejecting heat then what was the volume of the gas when it started rejecting the heat B PA n Po Po 2 V V V Vo V V A IZ Vo Correct Answer 12 T B 2V

15 A charge Q is kept at centre of a hemisphere S Another charge g is placed at any one point A B C and D At which point q should be kept so that Q flux through hemisphere remains 250 A 1 A 3 C S C 2 B 4 D