Physics Questions

mA c 200 mA b 100 mA d 20 mA C B S E P M T 2011 A12 An AC voltage is applied to a resistance R and an inductor L in series IfR and the inductive reactance are both equal to 32 the phase difference between 102 the applied voltage and the current in the circuit

I I Column 1 System string 2k ing string Column 2 Extension in spring at equilibrium MAVEVA JATHE ii iii iv mg 4k mg k mg 2k Column 3 Maximum amplitude of block so that string attached to block does not slack 2mg k R S 4mg mg 8k mg k

6 4kg 1 4 4 Consider three cases in equilibrium 60 60 Kg 4kg 60 Kg 4kg 111 60 K A man of mass 60 kg is holding the string connected to block of mass 4kg as shown Ther the incorrect statement is 1 Normal reaction will be maximum on man in first case 2 Normal reaction will be least in third case 3 Tension in the string held by man is least in third case 4 Tension in string held by man is maximum in second case

curves drawn between frictional 7 force f and applied force F for 2 bodies on ground Then correct statement is f 40 N A 20 N B F 1 0 0 2 Coefficient of static friction may be more for B 3 Coefficient of kinetic friction is same as coefficient of static friction for both A B 4 Coefficient of static friction

Mark Tor Review 01 2 hr m In Davisson Germer experiment the maximum intensity is observed at Scattering angle 50 and 54 volt Scattering angle 54 and 50 volt Scattering angle 50 and 50 volt None of these

49 In R L C series circuit the potential differences across each element is 20 V Now the value of the resistance alone is doubled then P D across R L an C respectively a 20 V 10 V 10 V c 20 V 40 V 40 V b 20 V 20 V 20 V d 10 V 20 V 20 V Karnataka CE

9 A p n photodiode is made of material with a band gap of 2 eV The minimum frequency of the radiation that can be absorbed by the material is nearly h 6 6 x 1034 the be 1 10 x 10 Hz 2 5 x 10 4 Hz 3 1 x 10 Hz 4 20 x 10 4 Hz

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

The kinetic energy of a 2 1 kg block moving across a horizontal frictionless surface increases linearly with time according to the following eq K t 4 t How far will the object move in m between t 1 85 s and t 5 01 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

4 3 2 Y 4r Y 9 A cube of side 40 mm has its upper face displace by 0 1 mm by a tangential force of 8 kN TH shearing modulus of cube is 2 4x 10 Nm 2 1 2 x 10 Nm

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

The graph in the broken line represents one for a given freq and intensity of the incident radiatio freq is increased and the intensity is reduced which of the following graphs of unbroken line repres new situation Where V in the variable potential diff of the source applied across the photo electric graph is plotted between variable p d and photo electric current Current A A A A B B C C D E P d V D D

D X masses are m 133 0g mg 228 0g mc 573 0g and mp 313 0g what are the coordinates of the center of mass if the origin is located at mass A Enter your x coordinate first followed nate t Answer Tries 0 10 is the moment of inertia about a diagonal axis that passes through masses B and D Answer Tries 0 10

horizontal plane with constant speed Its angular momentum about hinge X l m 1 Conserved 2 Only direction is conserved not the magnitude 3 Only magnitude is conserved not the direction 4 Neither magnitude nor direction

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

A block of mass 5 kg is suspended by two light strings 1 and 2 as shown in figure If T and T2 be tension in strings 1 and 2 respectively then the value of T T2 is g 10 m s 30 50 N O 30 N O 28 N 5 kg 60

2 The position x time t graph for a particle moving along a straight line is shown in figure The average speed of particle in time interval t 0 to f 8 sis x m 20 10 0 2 1 Zero 3 7 5 m s 468 A t s q 2 5 m s 4 9 7 m s IN

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

3 1 25 x 10 1 Nm 2 4 16 x 10 Nm 8 Two wires of length I radius r and length 21 radius 2r respectively having same Young s modulus are hung with a weight mg Net elongation is 2 1 3 3 mgl Y 3 mgl 2mr Y 2 mgl 3r Y 3 mgl 4rr Y

36 1 7777 F 3 of static friction is always more than the coefficient of kinetic friction A block of mass m is placed at rest on a rough horizontal surface with the coefficient of friction u The following figure shows four different ways in which a constant force F may be applied on the block Identify the situation in which the block can be moved with the least effort m m F 7777 2 T 4 m m F

17 A particle moves on a given straight line with a constant speed v At a certain time it is at a point P on its straight line path O is a fixed point Show that OP xu is independent of the position P

A lamina is made by removing a small disc of diameter 2R from a bigger disc of uniform mass density and radius 2R as shown in the figure The moment of inertia of this lamina about axes passing through O and P is I and Ip respectively Both these axes are perpendicular to the plane of Ip the lamina The ratio to the nearest integer is Io 2R 2R P

change If same torque was provided on a hard boiled egg raw egg to spin on a table then 1 Hard boiled egg will have higher angular acceleration 2 Raw egg will have higher angular acceleration 3 Both will have same angular acceleration 4 Information is insufficient

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

In the given figure all surfaces are smooth The system is released from rest Find the value of m in kg for which 1kg block does not slide on wedge 30 YOUR ANSWER 2 kg ATT 9

Sirius A has a luminosity of 26 LSun and a surface temperature of about 9400 K Part A What is its radius Hint See Cosmic Calculations 12 2 Radius of a Star Express your answer using two significant figures V A O

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

A conductor moves with a velocity 12m s at an angle of 90 to a magnetic field produced between two square faced poles of side length 2cm If the flux leaving the pole face is 5 Wb find the magnitude of induced emf in each case

of the following are correct a For a general rotational motion angular momentum L and angular velocity a need not be parallel b For a general rotational motion angula momentum L and angular velocity an always parallel c For general translational motion Line momentum P and velocity v are alwa parallel d For a general translation motion accelerati a and velocity v are always Parallel 1 a d 2 b d

Calculate the energy generated in MeV when 0 1 kg of Li is converted to He by proton bombardmen Given masses of Li He and H in a m u are 7 0183 4 0040 and 1 0081 respectively Li H 2 He Q

If two S H M of same frequency and amplitude are super mposed in same phase on the particle of mass m The motion of the particle will be 1 SHM 2 Oscillatory but not periodic 3 Periodic but not oscillatory

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

A uniform chain of mass m and length is held on a horizontal frictionless table with 1 2th of its length hanging over the edge of the table The wok done in pulling the chain up on the table is Options mgl n mgl 2n 1 2

a prism of refractive index 2 refracting angle A produces minimum deviation Dm of a r on one face at an angle of incidence 45 The values of A and Dm are respectively ONO No 45 45 45 60 60 30 60 45

is pulling a wagon on a rough surface with constant velocity Rough Surface A The net force on the system wagon is in forward direction B Nature of friction on both wagon and horse is same C The energy is lost due to friction acting on the horse D The friction supplies energy to the horse The total number of incorrect statements is 1 0 3 3 Consider three 2 2 4 4

se or decrease depending upon clock wise or anticlock wise sense of rotation 10 If ice of the poles will start melting the duration of day and night 1 Increase 2 Decrease 3 Not change 4 Depend upon th 40

Total number of correct statements are A Tension may be impulsive force B Gravitational force may be impulsive force C Spring force can never be impulsive force D Frictional force can never be impulsive 1 1 2 2 3 3 4 Zero

Dispersion of light in a medium implies that Light of different wavelengths travel with equal speed in medium Light of different frequencies travel with equal speed in medium Refractive index of medium is different for different wavelengths

iddle angle ches o the ce of rallel 9 A car is fitted with a convex side view mirror of focal length 20 cm Asecond car 2 8 m behind the first car is overtaking the first car at relative speed of 15 m s The speed of the image of the second car as seen in the mirror of the first one is 1 m s 2 10 m s 3 15 m s 4 m s 15 10

45 15 A rectangular coil of length 0 12 m and width 0 1 m having 50 turns of wire is suspended vertically in a uniform magnetic field of strength 0 2 Weber m The coil carries a current of 2 A If the plane of the coil is inclined at an angle of 30 with the direction of the field the torque required to keep the coil in stable equilibrium will be 2015 Pre a 0 12 Nm b 0 15 Nm c 0 20 Nm d 0 24 Nm 16 Two identical long conducting wires AOB and COD are placed at righ

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

13 4 A D C B Surface between blocks is sufficiently rough and surface between block and ground is smooth Assume starting from rest Which of the following is incorrect 10N 2kg 4kg A Block C 10N 16N Case T 2kg 1 2 kg A 2 2 kg B 3 4 kg A 4 4 kg B If v P at rt Then 4kg B Direction of motion 16N Direction friction

53 A planet of mass m revolves in an elliptical orbit around the sun so that its maximum and minimum distance from the sun are equal to r and rp respectively The angular momentum of this planet a relative to the sun is 2GMrpra V rp ra a m GMrpla V rp ra c m The b m d m 4GMrpa r ra GMrra 2 rp ra 59 magnitudes of the gravitational force at distance ro of a uniform sphere of

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

A A wedge free to move of mass M has one face making an angle a with horizontal and is resting on a smooth rigid floor A particle of mass m hits the inclined face of the wedge with a horizontal velocity vo It is observed that the particle rebounds in vertical direction after impact Neglect friction between particle and the wedge take M 2m vo 10m s tana 2 g 10m s a M

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

3 cm s 9 A ring of radius R is hung by a hail on its periphery such that it can freely rotate in its vertical plane The time period of ring for small oscillation is 1 T 2n 3 T 2T R g 2R g 2 T T R g 3R 5g 4 T 2

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