Basic Physics Questions and Answers

R For a constant current the current density electric field and drift velocity are inversely proportional to cross sectional area ol Answer 1 A To a metal wire of diameter d and length L when the applied voltage is doubled drift velocity gets doubled R For a constant voltage when the length is doubled drift velocity will be halved but drift velocity is independent of diameter ol Answer 2

25 Assertion Reason v u at formula is applied for projectile but cannot be applied for uniform circ motion v u at is applicable when an acceleration a is uniform

In Young double slit experiment 1000 nm d 1mm and D 1m If both the slits are havin equal intensities The distance s from central maxima at which intensity is half of maximu intensity is A 12 5 x 10 4 m B 2 5 10 4 m C 7 5 x 10 4 m D 1 25 10 4 m X

A regular polygon has 20 sides equal charges each of Q are placed at 19 vertices of the polygon and a charge q is pla at the centre of polygon If the distance of each vertex from the centre is a then net force experienced by q is B D 1 200q 40 a 1 qQ 40 a 1 19Qq 40 a2 zero

60 An ideal monoatomic gas undergoes a process in which the gas volume relates to temperature as VT constant Then molar specific heat of gas in this process is R b R a c 2 3R C 2 d None of these

The curve of angle of incidence versus angle of deviation shown has been plotted for prism The value of refractive in of the prism and i are A B V3 90 3 60 v3 2 32 2 60 90 84 70 IM 60 40 60 1

A straight segment OC of length L carrying a current i is placed along y axis Two parallel long current carrying wires are arranged at x a and x a as shown in dig each carry a current i then magnetic force on segment OC is 1 Y Question Type Single Correct Type 2 x a 3 14012 2T En 1401 4m En 14012 8 En L2 a2 a L a O L2 B O X x a

The distance time graphs below represent the motion of a car Match the descriptions with the graphs Explain your answers Descriptions 1 The car stopped 2 The car is traveling at constant speed 3 The speed of the car is decreasing 4 The car is coming back A C Distance Distance Graph A matches description Graph B matches description iraph C matches description Graph D matches description Time Time because because because because B D Distance Distance Time Time

vi In a branch of an electrical circuit shown in figure 5 118 R 1002 L 5H E 20V i 2A This current decreasing at a rate of 1 0A s Find Vat this instant ab R L 000000000000 mom Figure 5 118 E b

c directly proportional Q 29 The angle between the vectors 4 i 31 4k and 31 4j 6k is 90 b 45 c 60 d 0 0 20 Ucin the inversely proportional to g of Ris

A conducting sphere of radius R has charge Q on its surface If the charge on the sphere is doubled and its radius is halved the energy associated with the electric field will a increase four times b increase eight times c remain the same d decrease four times

c d Q 30 Using the gas equation PV nRT the dimension of R is a M L T K mol b c M LOT 2K mol d M L T K mol M 2L T 2K mol

A machine gun has a mass of 20 kg It fires 30 g bullets at the rate of 400 bullets per second with a speed of 400 ms What force must be applied to the gun to keep it in position Ans 4800 N

An electric field 301 201 Vm1 exists in the space If potential at the origin is zero then potential at 5m 3m is given b A 60 V 90 V 150 V Marks 4 00 240 V

Two immiscible liquids are kept in a vessel a shown A small hole is made in side wall c container so that horizontal range is maximum Find the horizontal range in cm to nearest integer g 10 m s 1 24 3 21 10 cm 20 cm P 2p 2 25

Figure shows two swimmers starting from poin A and B on opposite banks They started at same instant with a constant velocity Both of them star to swim in a direction parallel to line AB always eich The river flows towards the east 10 B bibul empo d A ogorci non River flow pbs 1 Swimmers A and B cannot collide 2 Swimmers A and B will definitely collid on line AB somewhere 3 Swimmers A and B will definitely collid somewhere to the east of line AB 4 Swimmers A and B will definitely collid

Q 20 The ratio of the time taken to reach the top most point and to come back to earth by a body thrown vertically upward is a c a b c d b 2 1 d it depends of the mass of the body For Question 21 25 two statements are given one labelled Assertion A and other Reason R Select the correct answer to these Question from the codes a b c and d as given below Both A R are true R is correct explanation of A Both A R are true but R is NOT the correct explanation of A A is true but R is false A is false R is true 1 1 1 2

In the figure a sphere rolls without slipping on a plank moving with velocity Vo The radius and angular velocity clockwise of the sphere is r and w respectively The velocity of centre of mass Vcm of the sphere w r t ground is 1 vo rw V cm Vo

Output Y of the given logic gate network is A Bo Question Type Single Correct Type 1 A B A B 2 A B A B 3 4 A B A B English None Q Review

23 What is the velocity ratio of the pulley arrangement shown in Fig 3 32 G W Fig 3 32 a If W 100 kgf the effort E needed to raise it is 30 kgf What is its mechanical advantage and efficiency for the given load 2 b How would you expect its efficiency to vary with the load Give reasons for your answer pulleys Th IV

Half life period of a sample is 30 min Its decay fraction at instant t is 4 and decay fraction at 5 instant t 9 is then t t interval is 10 Question Type Single Correct Type 1 30 min English 2 43 min 3 60 min Review Q 10 min

4 x 1 1 20 C If 80 cal heat is extracted from 4 gm ice at 10 C then its final temperature will be Question Type Single Correct Type 2 40 C 3 30 C English 4 50 C Review Q 13

A ball is projected in the vertical x y plane from a train moving in horizontal x direction with constant positive acceleration The trajectory of the ball as seen from frame of train cannot be Point of projection is origin A C X B D X X

Capacitor stored energy in which form Question Type Single Correct Type 1 Electric field 2 Magnetic field 3 Both electric Magnetic Review 4 None

At t 0 particle starts and moves in a circular path of radius R If tangential acceleration of the particle is a then find the time when the total acceleration vector makes an angle 45 with tangential acceleration vector

A particle moves in x y plane according to rule x a sin oot and y a cos oot The particle follows A an elliptical path B a circular path C a parabolic path D a straight line path inclined equally to x and y axes

5 A circular beam of light having a diameter 4 cr falls on a plane glass slab at angle of incidenc 60 If refractive index of the material of slab 3 then diameter of the refracted beam is 2 1 10 3 8 23 2 3 cm cm 2 2 cm 4 4 312 cm

Series for NEET 2021 Given diagram represents the potential energy curve of particle in a field Particle will be in equilibrium at position UN 1 at B and D 3 A R and G B C D X 2 at A and C 4 at A B C and D

A train moving with a speed of 60 km hr is slowed down uniformly to 30 km hr for repair purposes during running After this it was accelerated uniformly to reach to its original speed If the distance covered during constant retardation be 2 km and that covered during constant acceleration be 1 km find the time lost in the above journey A 1 min B 2 min C 4 min D 5 min

The fundamental frequency of an organ pipe is independent of small variation in temperature The coefficient of linear expansion of the material is a The temperatue of the tube at this instant is Na The value of N is

In the given block diagram of typical op amp what are A B C and D Input A B C D Output O A Dual input and unbalanced output differential amplifier B Dual input and balanced output differential amplifier C Voltage regulator D Power amplifier A Level Shifter B Dual input and balanced output differential amplifier C Dual input and unbalanced output differential amplifier D Normal amplifier A Dual input and balanced output differential amplifier Dual input and unbalanced output differential amplifier C Level shifter D Complementary symmetry push pull amplifier A Dual input and unbalanced output differential amplifier B Single input and balanced output differential amplifier C level shifter D Normal amplifier

010 t The capacitor and a resistor are connected in series across ac supply Which of the following phasor diagrams may be correct t 3 2 V wt wt wt Je ot 1 0 2 0 2 16 01 3 9 1 02x02 2 421 4 6671166 26 41 240 3 Of co

Straight line motion of a particle along x axis is represented by the following position x time t graph Then x m A C t sec Average velocity of the particle from t 0 to t 1sec is 3m s B Velocity of the particle at t 0 is 1 m s Acceleration of the particle at t 4 sec is 1 m s D 60 45 1 Average velocity of the particle from t 0 to t 4 sec is 1 m s

The velocity of light in glass whose refractive index with respect to air is 1 5 is 2 108 a certain liquid the velocity of light of found to be 2 5x108 ms The refractive index of liquid with respect to glass is A 0 64 B 0 80 C 1 20 D 1 44

When the light of wavelength 400 nm falls on a photoelectric emitter photoelectrons are just emitted For another emitter 600 nm is sufficient for liberating photoelectrons The ratio of work functions is 1 2 1 23 2 Pag

The refractive index of glass with respect to water is If the velocity and wavelength of light 8 in water are 2 25x108 ms and 5400 A then the velocity and wavelength of light in glass are B 1x108 ms 6075 A D 1x10 ms 4800 4 A 2 108 ms 4800 4 C 2x108 ms 6075 A

56 28 Pre Medical Physics Velocity of light in glass whose refractive index w rt 35 L air is 1 5 is 2x10 m Sec In a certain liquid the velocity of light is found to be 2 5x108 m Sec The refractive index of liquid w r t air is 1 0 64 2 0 80 3 1 20 4 1 44 a li t

Q12 When a vessel of certain height is filled with water velocity of the water jet that escapes from a hole at the bottom of the vessel gets reduced by a factor of 2 3 when two thirds of water is replaced by a floating lower density liquid The density of the floating liquid is closest to O A 0 44 g cm O B 0 33 g cm O c 0 25 g cm O D 0 17 g cm

3 1 00 and 0 064 4 0 034 and 1 0 GO0046 17 A thin Prism P with angle 4 and made from glass of refractive index 1 54 is combined with another thin Prism P made from glass of refractive index 1 72 to produce dispersion without deviation The angle of Prism P is 1 5 33 2 4 3 3 4 26 53

SolveLancer Test How much amount of fuel can raise the temperature of a 120 g water by 2 C If the calorific value of fuel is 2 J g SolveLancer Test a 500 g b 250 g c 405 g d 504 g a h

If a and b are two vectors then a b a 6 2ab cos In this formula is the angle betw A a and b B a C and and b A a and b D a b and a b

01 long horizontal conveyor is moving with a constant speed v 3 0 m s A small block of carbon is placed on the belt with zero initial velocity relative to the ground The block will slip a bit before moving with the belt leaving a black mark on the belt figure How long is that mark in m if the coefficient of kinetic friction between the carbon block and the belt is 0 20 and the coefficient of static friction is 0 30 O

Isothe CO 4 B Light containing two wavelengths A A falls normally on a Plano convex lens of radius of curvature R resting on a glass plate If the nth dark ring due to coincides with the n 1 th dark ring due to Prove that the radius of nth dark ring due to is given by 7 MR 1474

18 Choose the incorrect nuclear fusion reactions among the following NCERT Pg 455 1 H H H e v 0 42 MeV 2 H H2He n 3 27 MeV 3 H H2H H 4 03 MeV 4 e e 1 4 2 asks undatio

15 For a wavelength of 400 nm kinetic energy of emitted photoelectron is twice that for a wavelength of 600 nm from a given p The work function of metal is 1 1 03 eV NCERT Pg 395 2 2 11 eV

Two stones are projected from the top of a tower in opposite directions with the same velocity V but at 300 and 60 with horizontal respectively The relative velocity of first stone relative to second stone is

A particle of mass 4m at rest decays into particles of mass m and 3m The ratio of Broglie wavelength of two particles will INCERT Pg 4 1 1 1 2 2 4 3 2 4 1 NIIT JEE Fo

10 In a sample of radioactive material what fraction of the initial number of active nuclei will remain undisintegrated after half of the half life of the sample NCERT Pg 448 1 1 1 1 2 2 2 3 2 4 2 1 11 The natural boron of atomic mass 10 81 u is bun isotopes 108 and 11B The

5th I and III 14 The input signal given to a CE amplifier having voltage gain 100 V 20 mV cos 10t The correspond 6 ing output signal will be NCERT Pg 449 1 2 V cos 10t 6 2 2 V cos 101 3 2 Vicos 10 7 TH 6 di JEE Foun 4 2000 V cos 101 2 3 15 A common emitter amplifier is shown in the 18

A mass of 5 kg is suspended by a string A Another string C is connected to the lower end of the mass If a sudden jerk is given to C then 1 portion AB of string breaks 2 portion BC of string breaks 3 none of the strings breaks 4 the mass starts oscillating A B C