Basic Physics Questions and Answers

Two points A and B are lying in a uniform electric field as shown in figure The correc relation about the potential at point A and poin B will be A 1 VA VB 3 VA VB B 2 VA VB 4 VA VB

If E and V are electric field and electric potential respectively due to a point charge then which of the following graph best represent their variation K E 1 2 4 E 1 13

A spaceman in training is rotated in a seat at the end of a horizontal arm of length 5m If he can withstand acceleratie upto 9 g then what is the maximum number of revolutions per second permissible Take g 10 m s RPMT 200 1 13 5 rev s 2 1 35 rev s 3 0 675 rev s 4 6 75 revis

c PV P V PVT P V T 5 A steel metre scale is to be ruled so that the millimetre intervals are accurate within about 5 x 10 5 mm at a certain temperature The maximum temperature variation allowable during the ruling of the millimetre marks is a for steel 11 x 10 6 C a 8 C c 4 5 C b 9 C d 10 C

The period of oscillation of a simple pendulum is given by Vg where is about 100 cm and is known to 1mm accuracy The period is about 2s The time of 100 oscillations is measured by a stop watch of least count 0 1 s The percentage error in g is U U T 2 0 1 1 0 2

18 Let the transverse magnification poduced by spherical mirror be m Then the same position of small object along principal axis and mirror the longitudinal magnification will be Tonive 1 m 3 m 2 m LE E 4

Two small balls each of mass m are held by light strings of length as shown in the figure The initial separation between the balls is r At t 0 each ball carries a positive charge q Now the charge of each ball slowly changes and the variation is given by q t q 1 bt 5 where b is a positive constant The balls are also released at 1 0 Which of the following is correct A The balls will approach each other at constant speed B The balls will approach each other at increasing speed C The balls will approach each other such that the speed will first increase and then decrease D The balls will approach each other such that the speed will first decrease then increase

The Gauss seidal load flow method has following disadvantages Select the incorrect statement 1 Unreliable Convergence 2 3 Slow Convergence Choice of slack bus affects convergence A good initial guess for voltages is

A 0 2 m v 4 m s 1 4 m s 2 3 m s 3 1 m s neet prep UK A 0 2 m 41 A 0 4 m v 2 m s The figure shows a plot of PV T versus P for 1 00 103 kg of oxygen gas at two different x temperatures High Yielding Test Series Part Test 6 Half XIth Contact Number 9667591930 8527521718 2 b is periodic but d is not periodic 3 b and d are periodic 4 Only c is periodic 168 Page 130

13 A point particle of mass m moves along uniformly P the h 2m rough 30 R track PQR as shown in the Horizontal Q surface figure The coefficient of friction between the particle and the rough track equals u The particle is released from rest from the point P and it comes to rest at a point R The energies lost by the ball over the parts PQ and QR of the track are equal to each other and no energy is lost when particle changes direction from PQ to QR The values of the coefficient of friction and the distance x QR are respectively close to JEE Main 2016 Offline a 0 2 and 6 5 m b 0 2 and 3 5 m

A point mass m is lying at some distance from a spherical shell of mass m and radius r Then m Gravitational field inside the sphere is non zero Gravitational potential inside the sphere is non zero Gravitational field as well as gravitational potential inside the sphere is zero

Two very long wires parallel to the Z axis in xz plane and a distance 4a along x axis apart carry equal currents I in opposite directions as shown in the figure A cylinder of radius a and length L has its axis on the Z axis midway between the wires calculate the net upward magnetic flux through half of the curved cylindri cal surface above the x z plane A HOIL 7 B 2a 0 0 HoIL n3 C 2a 0 0 HoIL n2 D HOIL

33 mg of an unknown protein are dissolved in enough solvent to make 5 00 ml of solution The osmotic pressure of this solution is meas we 0 152 atm at 25 0 C Calculate the molar mass of the protein Round your answer to 3 significant digits

C Two bodies are thrown vertically upward with the same initial velocity of 98 metre sec but 4 sec apart How long after the first one is thrown will they meet A 10 sec C 12 sec B 11 sec D 13 sec 3

In the diagram 100 kg block is hanging from a pulley and force F is applied on the string to keep the system in equilibrium If the whole system is moving up with a constant velocity v then tension at point P in the string will be a 735 N b 1050 N c 1470 N 10 100 kg F

The wave function of a particle constrained to the x axis is shown in the histogram below 7 6 5 4 2 1 8 5 6 789 10 11 12 x n Calculate the probability that the particle will be found between x 4 00 and x 6 00 nm 1 2 3 4

00 20 A diffraction pattern is obtained using a beam of red light What happens if the red light is replaced by blue light O No change Diffraction bands become O narrower and crowded together Band become broader and farther apart

c The equation of state for 5 g of oxygen at a pressure P and temperature T when occupying a volume V will be a PV PV RT c PV b PV 5RT d PV 2 RT 16 to v in power a c 44 A sol

In an experiment to measure the height of a bridge by dropping stone into water underneath if the error in measurement of time is 0 1 s al the end of 2 s then error in estimating height of bridge is g 9 8 m s exact 0 19 m 1 96 m 0 98 m 0 12 m

Two candles initially of equal height h are at a distance of a from each other The distance between each candle and the nearest wall is also a With what speed the shadow of the left side candle will move along the left wall if left side candle burns down in the time and the right side in the time t CAR h

A man throws balls with same speed vertically upwards one after the other at an interval of 2 s What should be the speed of throw so that more than two balls are in the sky at any time a Only with speed 19 6 m s More than 19 6 m s c At least 9 8 ms b d Any speed less than 19 6 m s 11 In uniform circular motion

00 27 A parallel monochromatic beam of light is incident normally on a narrow slit A diffraction pattern is formed on a screen placed perpendicular to the direction of incident beam At the first maxima of the diffraction pattern the phase difference between the rays coming from the edges of the slit is O 0

A surface of glass with refraction index of 1 82 is covered with a thin film with refraction index of 1 62 Find the smallest thickness of the film in two cases a The light of wavelength 729 nm is most strongly reflected 112 5 b The light of wavelength 729 nm is most strongly transmitted 225 x nm nm

Example 13 1 The density of water is 1000 kg m The density of water vapour at 100 C and 1 atm pressure is 0 6 kg m The volume of a molecule multiplied by the total number gives what is called molecular volume Estimate the ratio or fraction of the molecular volume to the total volume Occupied by the water vapour under the above conditions of temperature and pressure wer For a given mass of water molecules density is less if volume is large So the me of the vapour is 1000 0 6 6 104 s larger If densities of bulk water and water ecules are same then the fraction of cular volume to the total volume in liquid is 1 As volume in vapour state has ased the fractional volume is less by the amount i e 6x10 ample 13 2 Estimate the volume of a er molecule using the data in Example 1 er In the liquid or solid phase the the mas a molecule of water is 0 018 6 x 10 ka 3 x 10 20 kg Therefore a rough estimate of follows volume of a water molecule is as Volume of a water molecule 3 x 10 26 kg 1000 kg m 3 x 10 29 m 4 3 Radius Hence Radius 2x10 10 m 2 A Example 13 3 distance between atoms distance in water Use the data given in Examples 13 1 and 13 2 What is the averag interatom 0

Q 2 When the angle of incidence on a material is 60 the reflected light is completely polarized The velocity of the refracted ray inside the material is in ms O 3 10 00 25 108 O 3 108

B done by the gas from B to C and on the gas from D to A 2 Three stars A B C have surface temperatures TA T and To A appears bluish B appears reddish and C appears yellowish We can conclude that a TA Te TB c TB TC TA b TA TB TC d TC TB TA

A 4 BVA 2 50 A ball A of mass 3m is placed at a distance d from the wall on a smooth horizontal surface Another ball B of mass m moving with velocity u collides with ball A The coefficient of restitution between the balls and the wall and between the balls is e a the velocity of ball B after collision is u 3e 1 4 b the velocity of ball B after collision is u 2e 1 4 c after collision ball A will move away by d 2e 1 distance 2e 1 during the time ball B returns back to wall d after collision ball A will move away by during the time ball B d e 1 distance 3e 1 returns back to wall 2h d 4 c d

Question No 19 Two ends of a train moving at constant acceleration pass a point with speed of 12 m s and 24 m s respectively The speed with which middle point of the train passes the same point is approximately O 16 m s O19 m s 22 m s View in English O 20 m s

Two loops P and Q are made from a uniform wire The radii of P and Q are r and 12 respectively and their moments of inertia are I and 12 respectively If 2 4 then 2 I r 2 A 43 4 3 C B D 43 WIN 4 3 equals

Question No 28 A mass of 6 kg is suspended by a rope of length 2 m as shown in figure A force of 80 N is applied at mid point Pas shown What angle the rope makes with vertical under equilibrium Take g 10 m s 1 m P 1m 0 6 kg 37 459 53 60 80 N

Find the point on the line joining them at which electric field intensity is zero 9 Derive lens maker s formula for a thin convex lens 10 a Draw equipotential surfaces corresponding to the electric field that uniformly

If the momentum of an electron is changed by A p then the de Broglie wavelength associated with it changes by 0 50 The initial momentum of the electron will be O O AP 200 Ap 199

Q 8 Moderate 1 O Unchanged Double the earlier value 00 16 The frequency of the incident light falling on a photosensitive metal plate is doubled the kinetic energy of the emitted photoelectron is O More than doubled Less than doubled 500

For the velocity v time 1 graph shown below what is the average velocity of object during first 7 seconds 10 m s 01 3 O 4 2 m s O 6 5 m s O 5 7 m s O 5 0 m s 5 7 t s

Q 1 00 4 e oam 1 00 33 In the Bohr model of a hydrogen atom the centripetal force is furnished by the coulomb attraction between the proton and the electron If a is the radius of the ground state orbit m is the mass and e is charge on the electron and is the vacuum permittivity the speed of the electron is O

13 A glass marble whose mass is 20gms falls from a height of 0 25 m and rebounds to a height of 1 6m If g 9 8 m s find the impulse acting on the fall in N s 1 0 2 2 0 4 3 0 252 4 0 534 11 71

378 45 A metal wire of length L and area of cross section A is attached to a rigid support Another metal wire of length L and of the same cross sectional area is attached to the free end of the first wire A body of 48 A mass M is then suspended from the free end of the second wire If Y and Y are the Young s moduli of the wires respectively the effective force constant of the system of two wires is W SCI 10 a Y Y A c a b 2 Y L Y 4 c YY A 1 4 1 4 YY A 44 2 d A 44 2 49 A An ang sam

In the Bohr model of the hydrogen atom let R V and E represent the radius of the orbit the speed of electron and the total energy of the electron respectively Which of the following quantities is proportional to quantum number n O E

If dimensions of critical velocity Vc of liquid flowing through a tube is expressed as n p r where n p r are coefficient of viscosity density and radius of tube respectively the value of x y z is Question Type Single Correct Type 1 2 3 zero 1 1

View in English From top of a tower 100 m high a ball is dropped and at the same time another ball is projected vertical up from ground with speed of 40 m s The two balls will meet g 9 8 m s O 56 m above ground 30 6 m below the top 40 8 m below the top 40 8 m above ground

49 A body A is projected upwards with velocity Another body B of same mass is projected t angle of 45 with the horizontal Both reach the same height What is the ratio of their initial kind energies a 1 4 c 1 2 b 1 3 d 1 9 A car is initially at rest 330 m

During an adiabatic process the cube of the pressure is found to be inversely proportional to the fourth power of the volume Then the ratio of specific heats is Question Type Single Correct Type 1 2 3 4 1 1 33 1 67 1 4

4 34 The lengths of two cylindrical rods are measured as 5 62 0 01 cm and 2 0 02 cm What is maximum percentage error in measurement of difference of lengths of two cylinders 1 6 2 34 1 95

Q 12 Moderate 4 1 05 28 O An observer A sees an asteroid with a radioactive element moving by at a speed 0 3c and measures the radioactivity decay time to be T Another observer B is moving with the asteroid and measures its decay time as T Then TA and T are related as below B

line joining their centers of mass such that at rest If the collision takes place along the the fraction of K E transferred by the their total kinetic energy is conserved and 8 colliding particle is then the mass of p and the mass of Q bears a ratio 8 3 2 9 83 2 34 2 1

Find the wavelength of a tennis ball with speed 50 0 m s and mass 58 5g Explain why we do not observe wave like properties when the ball hits the net ensure to address what wave like properties we could theoretically see link to a formula

377 40 A particle is executing simple harmonic motion of amplitude 5 cm and period 6 s How long will it take to move from one end of its path on one side of mean position to a position 2 5 cm on the same side of the mean position a Is c 3s b 1 5 s d 3 5 s 41 The P V diagram of a gas undergoing a cyclic process ABCDA is shows

a 1 r only c m r 2 d monly A vessel contains a mixture consisting of m 7 g of nitrogen M 28 and m 11 g of carbon dioxide M 44 at temperature T 300 K and pressure P I atm The density of the mixture is a 1 446 g per litre b 2 567 g per litre c 3 752 g per litre d 4 572 g per litre 8 W a E c 9 C 10

32 Three large non conducting plane of charge with charge densities o 20 and 30 are arranged as shown The field lines of electric field is correctly represented by 20 30 ash Tower 8 Pusa Road New Delhi 11000 DI

Question No 14 A ball is thrown vertically upwards with velocity of 20 m s from top of a tower 25 m high What is maximum height reached by ball from ground ga O 30 m O 40 m O 45 m O 75 m