Basic Physics Questions and Answers

A solenoid has 2000 turns wound over a length of 0 3 m Its cross sectional area is equal to 1 2x10 m Around its central cross section a coil of 300 turns is wound If an initial current of 2 A flowing in the solenoid is reversed in 0 25 s the emf induced in the coil in mV is

Copper The work function for sodium and copper are 2 eV and 4 eV respectively Which of them is suitable for a photo cell with 4000 light Sodium Mark for Review Both 01 23 hr mi

Q4 of 90 Mark To reach your school at 10 30am let you start at 10 00am First you move 800m towards east then 600m towards north and finally 200m towards west Then net displacement is X

The nucleus 64Cu half life 12 7h is known to decay by electron capture 61 contribution to total decay rate and B decay 39 contribution to total decay rate Partial half lives for electron capture and decay respectively are Question Type Single Correct Type 1 2 3 20 8h 32 6h 28h 32 6h 61h 39h

Assuming earth is a smooth sphere of radius Re and mass Me If a particle is thrown horizontally tangentially from earth with half of escape velocity then find out maximum distance of particle from centre of earth and trajectory of particle in subsequent motion Question Type Single Correct Type 1 2 3 Re circular 8Re elliptical 4Re straight line

If the momentum of a proton is changed by an amount Po the corresponding change in the de Broglie wavelength is found to be 0 25 Then the original momentum of proton was O Po hr mi 100Po

A body is projected from the ground for horizonta range 100 m At the highest point of its path breaks apart into two identical part P and Q If comes to rest then the horizontal distance of the point Q from the point of projection is 2 250 m 4 50 m 1 200 m 3 150 m

A particle is moving along x axis and its velocity v Vs position x graph is a curve as shown in figure Line PQR is normal to curve at point Q then instantaneous acceleration of particle at x 2m is v m s 1 4 m s Vo 2 8 m s P R 2 0 4 0 x m 3 2 m s 4 insufficient information

A spectral line 5000 in the line coming from a distant star is observed as 5010 The receding velocity of the star is O 1 2 x 107 cm s 6 x 105 m s hr mi O 1 2 x 107 km s

1 38 A particle moves from rest in a straight line with alternate acceleration and retardation of magnitudes a and a respectively during equal intervals of time t Find the space it has described at the end of 2 n such intervals Ans n a a a 2n 1

7 Monochromatic green light of wavelength 5 x 10 m illuminates a pair of slits 1 mm apart The separation between consecutive bright fringes on the interference pattern formed on a screen 2 m away is 0 25 mm 0 1 mm 1 0 mm 2001 mm

Consider two non conducting discs touching each other at point P as shown Their uniform surface charge densities and radius are shown in figure Potential at point P is equal to R 2 22R GR TEO GR 2TEO GR P 20

43 Two ends of a spring are displaced along the length of the spring All displacements have equal magnitude In which case s the tension or compression in the spring will have a maximum magnitude A The right end is displaced towards right and the left end towards left B Both ends are displaced towards right C Both ends are displaced towards left D The right end is displaced towards left and the left end towards right 1 A and D 2 B and C

If in an interference pattern has maximum and minimum intensity is 36 1 ratio then the ratio of amplitudes is 3 4 07 4 O 4 7

Two concentric and R R respectively between R and R is thin metallic shells of radii R R bear charges Q and Q Then the potential at distance r D K Q Q Q 1 r 3 K Q Q r R 2 K 2 Q 4 K Q R R

The angular width of central maxima in Fraunhoffer diffraction with the light of wavelength 6000 and slit width 12 x 10 5 cm is 2 rad 3 rad hr miny O 1 rad

A bicromatic light consisting of wavelength 5000A and 6000A is used to obtain interferance pattern in youngs double slit experiment is 1mm and the distance between plane of slits and screen is 100cm then the least distance from the central maximum where bright fringes due to both the wavelength coincide is 14 28

The angle of polarisation for a pair of medium is 60 then the critical angle is sin 3 tan 3 O cos 3 hr min sin 1

A cubicla room is formed with 6 plane mirrors An insect moves along the diagonal of th floor with uniform speed The speed of its image in two adjacent walls is 20 2cm s Then the speed of the image formed on the roof is ONO 20cm s 40 cm s 20 2cm s 10 5cm s

What should be the wavelength of the photon that enters when there is a quantum jump from level 1 to the last occupied level of a Neon atom A 0 079 nm B 1 02 nm C 0 315 nm Correct answer is letter C process needed

position x graph for a particle is shown below The particle is of mass 10 kg and is moving in the positive x direction 7 Its initial position is x 0 and inital velocity is 1 m s The velocity at x 10 is 4 2 1 4 m s P in watts 3 3 2m s 10 in m 2 2 m s 4 100 3 m s

If the shift of wavelength of the light emitted by a star is towards violet then this shows that star is Stationary Moving towards the earth Moving away from the earth None of these

1 d F F A F 2 The lever force F is usually some weight to be lifted It is called the load and its distances from the fulcrum d is called the load arm Force F is the effort applied to lift the load distance d o the effort from fulcrum then mechanica advantage will be 2 d F F 2 B F 3 F F 2 4 1 FF

If v P qt rt Then net force acting on this particle will be zero at t 2 if 1 p 3 q 0 1 3 2 9 3 4 3 different bodies Bot

An alternating voltage E Eo sin wt is applied across a coil of inductor L TH current flowing through the circuit at any instant is ONO No Eo wL Eo wL sin wt 2 sin wt 2 EowL sin wt T 2 27

What are the human body examples of class 2 and class 3 levers A nut cracker of length 9 cm has its effort situated at a distance of 6 cm from t

by the equation A reflecting sur x y a A ray travelling in negative x direction is directed towards positive y direction after reflection from the surface at point P Then co ordinates of point P are 1 0 8a 0 6a a a 3 2 y 2 0 6a 0 8a 1 2 4 22

Let denote the dimensional formula of the permittivity of vacuum If M mass L length T time and I electric current Then No 80 M L T 1 20 ML 3741 1 80 M L T 1 2

The period of oscillation of spring block system shown in the figure is Assume pulley and spring to be ideal 1 2T 3 2 m 3k 3m 3k 0000000 eeeeeee O k par m 2 2 4 2 217 4m 3k Tm m

3 2 x 10 m 4 100 m Three bars having length 1 21 and 3 and area of cross section A 2A and 3A are joined rigidly end to end Compound rod is subjected to a stretching force F The increase in length of rod is Young s modulus of material is Y and bars are massless 1 3 13FI 2AY 9F1 AY 2 4 FI AY 3 FI AY

For four non coplanar and non collinear vectors P Q R S if P Q R S 0 then which of the following must be incorrect 1 P Q R SI 2 P Q R S 3 P Q R S will be in same plane 4 P Q R S

A man is measuring his actual weight by weighing machine as shown in figure The mass of man is 60 kg Mass of Weighing machine is 20 kg and mass of lift is 30 kg pulley is smooth and string is massless g 10m s HO The tension exerted by the man on the string A 6600 N B 1800 N C 1110 N D 800 N

Stale If multiplication factor K 1 the operation of the reactor is said to be critical Control rods are made out of the neutron absorbing material such as cadmium Water is used as moderator in Apsara reactor BARC Mumbai For thermonuclear fusion reaction temperature of system should be of order of 10 K to overcome the coulombic repulsion

If photon energy is near about 3 5 eV then it causes the sunburn i e to break the bond in molecules of human ski This corresponds to the wavelength in the O X ray region O Visible region O IR region Ouv region

e A ball of mass m is suspended by a massless string of length from a fixed point A ball of mass 2m strikes in the direction of 0 45 from horizontal sticks to it 2m 45 m the initial velocity of 2m is x g so that system deflects by the velocity at highest point of trajectory is V then find x y and if string is cut at 6 60 and 2

Question 2 A particle approaches from very large distance towards concave mirror along the principal axis By the time the particle reaches the mirror the distance between the particle and its image B C first decreases then increases first increases then decreases first increases then decreases and then again increases first decreases then increases and then again decreases My Answer Correct Answe

The displacement of a pendulum is the angle measured from the vertical For a certain pendulum the displacement is 8 16 sin 4t 0 754 where is measured in radians Determine the maximum angle from the vertical position

In the given figure a block A rests on a smooth triangular block B and the block B is moved at an acceleration of a 2 m s along the plane A normal force on block A due to block B is m g a B Acceleration of block A relative to block B is acos 0 A B If friction is present between block A and B the coefficient should be greater than C cose for no relative motion between A and B If friction is present between block and A and B the coefficient of friction should be a cos 0 D greater than g a sin 0 2 for no relative motion between A and B Q 2

A battery of internal resistance one ohm and emf 3 volt sends a current through Imetre of uniform wire of resistance 50 The poles of the cell of emf 1 4volt are connected to two points on the wire so that no current passes through this cell Then the potential gradient of the wire is

AB Determine the resistance RR between points A and B of the frame made of thin homogeneous wire figure assuming that the number of succes sively embedded equilateral triangles wide sides decreasing by half tends to infinity Side AB is equal to a and the resistance to unit length of the wire is p a 2 a 2 B

What is correct answer Q 2 Two pipes are connected by a manometer as shown in the figure below Differential readings are 03 0 7 m and 10 m as shown on the figure Determine the pressure difference PA PB between pipes A and B 30p Water 4 0 3 m 0 7 m fluid SG 2 Water 10m

26 180 The colour of bright fringe nearest to central white fringe in interference pattern with white light will be X Blue Red Yellow

For a black body maintained at temperature To K the maximum radiation occurs at wavelength o If the temperature is raised to T K To 2 corresponding wavelength is If Ao 3000 then value of o is O 8 000 6 000 O 9 000

11 The electric field in a certain region is given by E 51 3 kV m The potential difference VB VA between points A and B having coordinates 4 0 3 m and 10 3 0 m respectively is equal to 1 21 kV 3 39 kV 2 21 kV 4 39 kV

4 A point charge Q is placed at the centre of a hemisphere Find the ratio of electric flux passing through curved surface and plane surface of the hemisphere a 1 1 b 1 2 c 2 1 d 4 1

d none of these 60 A black spot is present at the center of the face of an equilateral prism A man placed his eye close to the opposite corner He sees two images of the spot at an angular separation of 60 What is the condition on the refractive index of the prism very Eye a 2 b 2 Black spot c 2 3 d 2 3

9 In a certain hypothetical radioactive decay process species A decays into species B and species B decays into species C according to the given reactions A 2B particles energy B 3C particles energy The decay constant for species A is A 1 sec and that for species B is A 100 sec Initially 104 moles of species of A were present while there were none of B and C It was found that species B reaches its maximum number at a time to 2 In 10 sec Calculate the value of 0 maximum number of moles of B

1 In LCR series circuit source voltage is 120 V and voltage across inductor is 50 V If voltage drop across resistance is 40 V then determine voltage in capacitor a 10 5 8 2 v c 20 5 8 2 V b 10 5 8 2 V d 10 5 7 2 V AIIMS

A particle P is moving on a circle under the action of only one force which always acts at the towards a fixed point O lying on the circumference Find ratio of moment when 0 45 C is centre of circle L de to

hree point charges are placed at the corners of a rectangle as shown in figure If a 54 cm and q 25 C then calculate the magnitu lectric force in N on the charge 3q 9 a 9 2 a 4q Useful constants k 9 00 109 N m C 0 8 85 10 12 c N m HO 4TTx 10 7 T m A mp 1 67 10 27 kg me 9 11 10 31 kg e 1 6 10 19 C 100m 2