Physics Questions

What will happen to the current in this circuit as frequency increases 5 V RMS 0 22 F A Current will remain the same B Cannot tell not enough information given C Current will decrease D Current will decrease to a minimum and then increase Se

A bird in air is diving vertically downward over a tank with speed 5 cm s while base of tank is silvered A fish in the tank is rising upward along the same line with speed 2 cm s water level is falling at rate of 2 cm s take water 4 3 L Speed of image of fish as seen by bird directly is 6 cm s B Speed of image of fish as seen by bird directly is 3 cm s Speed of image of fish as seen by bird after reflection from mirror is 3 cm s D Speed of image of fish as seen by bird after reflection from mirror is 6 cm s

100H C 1 F R 10k When all the switches are open V2 reads 100V All the voltmeters are hot wire voltmeter which read r m s value of voltage Initially S1 S2 and S3 are open In the figure frequency of the A C source is 50 THz with L S S R wwwwww S3 At certain instant of time voltage across R is increasing magnitude of potential difference across inductor and capacitor simultaneously increases or decreases Readings of all other voltmeters are also equal to 100V When S and S2 are both closed reading of V4 remains 100v When only S closed reading of V4 decreases

occurs in green plants Study the diagrams and answer the questions that follow SUNLIGHT SUNLIGHT 1111 Green Plant A C D Mouse Dead Mouse Alive 1 Name the physiological process occurring in the green plant that has kept the mouse alive ii Explain the physiological process mentioned above 5 18 ICSE 20 the form of a chemical equation process in v Represent the above mentioned physiologic stated in for life on earth iv What is the significance of the process a 1 Why and the mouse an in

In Bohr atomic Model regarding transition of electron for hydrogen like atom following observation were noted Column 1 Initial energy level 1 N 3 11 N 5 III N 2 IV N 4 O II ii Q O IV iv R O IV iv S Column 2 Final energy level O III iii P 1 N 2 1 N 4 iii N 1 iv N 3 Column 3 Series Kinetic energy of electron will become 4 times of initial in the transition P Lyman series Q Brackett series R Paschen series S Balmer series

A flexible chain of weight W hangs between two fixed points A and B at same level The inclination o the chain with the horizontal at the two points of support is 60 What is the tension of the chain at the point P where inclination of chain with horizontal is 30 A B 2W 3 W 2 C W W B

A ball of radius r moving with a speed v collides elastically with another identical stationary ball The impact parameter for the collision is b see figure 2 1 1 After collision ball 1 will come to rest and ball 2 will move with velocity making an b angle sin below the x axis 2r 2 After collision ball 1 will move with some b finite velocity making an angle cos 2r above x axis and ball 2 will move with some b 27 below 2r different making an angle sin the x axis 3 For perfectly elastic head on collision b 0 and for perfectly elastic oblique collision 0 b 2r 4 The balls must scatter at right angles

4 A student uses a simple pendulum of exactly 1m length to determine g the acceleration due to gravity He uses a stop watch with the least count of 1 s for this and records 40 s for 20 oscillations For this observation which of the following statement s is are true 2010 a Error AT in measuring 7 the time period is 0 05 s b Error AT in measuring T the time period is 1 s c Percentage error in the determination of g is 5 d Percentage error in the determination of g is 2 5

A man walking downhill with velocity u finds that his umbrella gives him maximum protection from rain when he holds it such that the stick is perpendicular to the hill surface When the man turns back and climbs the hill with velocity u he find that it is most appropriate to hold the umbrella stick vertical Find the speed of raindrops w r t ground The inclination of the hill is 0 30 u 52 m s

41 An electron accelerated through a potential difference V passes through a uniform transverse magnetic field and experiences a force F If the accelerating potential is increased to 2V the electron in the same magnetic field will experience a force A F B F 2 C 2 F D 2F

A block of mass M is placed on a horizontal surface It is tied with an inextensible string that passes through ideal pulleys A mass m is connected to the pulley as shown For what value of m the block M will accelerate towards the fixed pulley 1 N 3 M 2 M M HO m

9 a Determine and sketch the output voltage for the following circuits The diode is made of silicon with forward voltage drop 0 7 V ii 10 V 0 10 V R o W 0 1 0 kn 3 3 V 5 1 V 18 V A 18 V R w 10 kf2 12 V R 100 2 220 0 IN914 UP

W motor car is travelling at 60 m s on a circular road of radius 1200 m It is increasing its speed at the rate of 4 m Find the acceleration of the car is in m s

3 45 4 50 32 When a thin film is illuminated by a parallel bear of 6000 A of light wavelength 7 fringes are observed in a certain region of the film How many fringes will be observed in the same region of the film if light of wavelength 420 A is used 1 6 2 10

Electromagnetic radiation whose electric component varies with time as E C C C3coswt coswot here C C and C3 are constants is incident on lithium and librates photoelectrons If the kinetic energy of most energetic electrons be 0 592 10 19 J Given that wo 3 6 10 5 rad s and w 6 x 1014 rad s What is the work function of lithium in eV take planks constant h 6 6 10 34 MKS

12 Huygens principle of secondary wavelets may not be used to 1 Find the new position of a wavefront 2 Explain Snell s law 3 Explain laws of reflection 4 Explain particle behaviour of light 13 It is found that when waves from two identical coherent sources superpose at certain point with same individual intensity then the resultant intensity is equal to the intensity of one wave only This means that phase difference between the two waves at that point is 1 Zero 3 27 3 14 Two slits are separated by a distance of 1 mm are illuminated with red light of wavelength 6 5 x 10 7 metre The interference fringes are observed on a screen placed 1 metre away from the slits The distance between 3rd dark fringe and fifth bright fringe is equal to 1 0 65 mm 3 3 23 m 3 2 1 63 mm 4 4 68 mm 15 When a thin transparent plate of thickness t and refractive index u is placed in the path of one of 2 T 3 4 1 t 2 1 t 4 ut 16 The minimum thickness of a soap bubble film u 1 33 that results in constructive interference in the reflected light if the film is illuminated with light whose wavelength in free space is 600 nm is 1 112 50 nm 3 400 nm 1 0 36 3 0 72 two interfering beam of light the centestioner between two waves at the position central is 1 1 t 2 225 26 nm 4 176 5 nm 17 The light of wavelength 6328A is incident on a slit of width 0 2 mm perpendicularly the angular fringe width of central maxima will be 2 0 18 4 0 09 1 18 The diameter of the objective of a telescope is a its magnifying power is m and wavelength of light is A The resolving power of the telescope is 1 22 a Am 1 22a 3 19 A beam of unpolarised light passes through a tourmaline crystal A and then it passes through a second tourmaline crystal B oriented so that its principal is parallel to that of A The intensity of the emergent light is Now B is rotated by 45 about the ray The emergent light have intensity 1 1 1 202 3 9 2 4 2 2 3 20 In Young s double slit experiment interference pattern is found to have an intensity ratio between bright and dark fringes as 9 Then amplitude ratio of the wave reaching the screen from two sources is 3 a 1 22 a 1 22 m A beam of monochromatic green light is diffracted by a slit of width 0 550mm The diffraction pattern forms on a wall 2 06m beyond the slit The distance between the positions of zero intensity on both sides of central bright fringe is 4 10mm Wavelength of the light used is 1 400mm 2 525mm 4 547mm 3 642mm 22 A soap bubble 250nm thick is illuminated by white light The index of refraction of the soap bubble is 1 36 Which wavelength is missing in range of visible light for reflected rays 1 300mm 3 400mm 2 2 4 3 23 Maximum distance from diffraction slit of slit width a upto which ray optics holds for wavelength is 2 600mm 4 680nm N E

Column II gives certain systems undergoing a process Column I suggests changes in some of the parameters related to the system Match the statements in Column I to the appropriate process es from Column II 2009 Column I A The energy of the system is increased p B Mechanical energy is provided to the system which is q converted into energy of random motion of its parts Column II System A capacitor initially uncharged Process It is connected to a battery System A gas in an adiabatic container fitted with an adiabatic piston Process The gas is compressed by pushing the piston C Internal energy of the system is converted into its r System A gas in a rigid container mechanical energy D Mass of the system is decreased t Process The gas gets cooled due to colder atmosphere surrounding it s System A heavy nucleus initially at rest Process The nucleus fissions into two fragments of nearly equal masses and some neutrons are emitted System A resistive wire loop Process The loop is placed in a time varying magnetic field

Quesuon No 6 For Example If first third and fourth are the ONLY three correct options for a question with second option being an incorrect option selecting only all the three correct optio in 4 marks Selecting only two of the three correct options e g the first and fourth options without selecting any incorrect option second option in this case will result Selecting only one of the three correct options either first or third or fourth option without selecting any incorrect option second option in this case will result in 1 marks incorrect option s second option in this case with or without selection of any correct option s will result in 1 marks A particle is moving in a circle of radius 2m with angular velocity w 2t2 4t where t is time in sec and wis in rad s Angular acceleration of the particle at t 2 sec is 4 rad s Angular acceleration of the particle at 2 sec is 8 m s Angular acceleration of the particle is constant 32 Angle rotated by particle in time interval t 0 to t 4 sec is 3 radian

38 Four wires each of length 2 0 metre are bent into four loops P Q R and S then suspended in uniform magnetic field Same current is passed in each loop Which statement is correct A Couple on loop P will be highest B Couple on loop Q will be highest C Couple on loop R will be highest D Couple on loop S will be highest P R S

1 If a source is connected to points a b the charge on all capacitors are equal If it is connected to points m n then also charge on all capacitors are equal m 2 F C 5 F n A C 3 5 F B C 2 F C If source of voltage 6 volts is connected between m b charge on C 5 C D If source of voltage 6 volts is connected between a n the charge on C 2 C

This section contains FOUR 04 questions Each question has FOUR options ONLY ONE of these four options is the correct answer For each question choose the option corresponding to the correct answer Answer to each question will be evaluated according to the following marking scheme 3 3 IF ONLY the correct option is chosen Full Marks Zero Marks Negative Marks 1 If none of the options is chosen i e the question is unanswered In all other cases In the given diagram if the spring connecting D and C is cut then what will be the accelerations of blocks A B C D at that insta leon0000 4kg 13kg

39 A beam of well collimated cathode rays traveling with a speed of 5 x 10 m s enters a region of mutually perpendicular electric and magnetic fields and emerges undeviated from this region If B 0 02 T the magnitude of electric field is A 10 V m B 2 5 x 10 Vm C 1 25 x 10 V m D 2 x 10 Vm

In the most general form of Bernoulli s 2 V P equation W z constant 2g each term represents a energy per unit mass energy per unit weight b c energy per unit volume of the above of

A small object of mass m and of charge q slides down along a frictionless slope of a elevation from a height h From the midpoint of the slope it enters into a region of uniform horizontal electric field and it decelerates and stops at the bottom of the slope m q E h e A The magnitude of E istana B The normal reaction on block before dotted line and after dotted line remains the same C The magnitude of acceleration before and after dotted line remains the same D The speed at height from bottom is V

uations y 7 6 interfere m intensity of In Youngs double slit experiment if the widths of the slit are in the ratio 4 9 ratio of intensity of maxima to intensity of minima will be width of slit is directly proportional to amplitude of interfering waves 1 25 1 2 9 4

In any fission process the ratio mass of fission products mass of parent nucleus 1 less than 1 2 greater than 1 3 equal to 1 4 depends on the mass of parent nucleus is 2005

The equation is based on the following assumptions regarding the flow of fluid a steady frictionless incompressible and along a streamline b steady frictionless uniform and along a streamline steady incompressible uniform and along a streamline steady frictionless incompressible and uniform 1 c d z constant w 2g

42 A proton and an electron both moving with the same kinetic energy enter into a region of magnetic field directed perpendicular to the velocity of the particles They will now move in circular orbits such that A their time periods will be same B the time period for proton will be higher C the time period of electron will be higher D their orbital radii will be same

Assertion A A point charge is lying at the centre of a cube side The electric flux emanating from each surface of the cube is 1 6 of the total flux Reason R According to Gauss theorem total electric flux through a closed surface 1 times the enclosing a charge is equal to itud 0

A block of mass 3 kg is placed on a smooth horizontal surface A small block of mass 2 kg is place over the 3 kg block Now a force of 10 N is acted upon 3 kg blocks For both blocks to move together le friction cofficient between block have minimum value of u Ho Then choose CORRECT statement u 2kg 3kg 10N

You are shown a photo of a car driven on a vertical inside wall of a huge cylinder with a radius of 10 m The coefficient of static friction between the car tires and the cylinder is us 0 25 The minimum speed in m s at which the car can be driven like that is 5x Find x

32 A charged particle moving along ve x direction with a velocity v enters a region where there is a uniform magnetic field B from x 0 to x d The particle gets deflected at an angle 9 from its initial path The specific charge of the particle is where d qB A VCOS Bd B v tan Bd C Bd D v sine Bd

A particle is projected from ground at an angle 9 At a certain instant the velocity vector of particle makes an angle a with horizontal g dv modulus of gsina dt Tangential acceleration has magnitude of g sin a Normal radial acceleration g cos a

5 Two polarising sheets are placed with their plane parallel so that light intensity transmitted maximum Through what angle must either shee be turned so that light intensity drops to half th maximum value 1 30 3 60 2 45 4 90

If five particles of mass m are placed on the vertices of a square pyramid of side length a and height a as shown in the figure then find out the centre of mass for the given system m m a a m O m a m

Illustration 5 60 Two particles are located on a horizontal plane at a distance 60 m At t 0 both the particles are si multaneously projected at angle 45 with velocities 2 ms and 14 ms respectively Find 1 u 2 m s A 45 ik 60 m B42 14 m s 45 B Fig 5 122 a Minimum separation between them during motion b At what time is the separation between them minimum

x 10 7 d on a s The bright 2 2 20 In Young s double slit experiment interference pattern is found to have an intensity ratio between bright and dark fringes as 9 Then amplitude ratio of the wave reaching the screen from two sources is er 2 2

A particle of mass m is moving with constant velocity vo along the line y b At time t 0 it was at the point 0 b At time t Angular momentum of particle about origin is 2mvob Angular momentum of particle about origin is having value equal to mvob Torque acting on particle about origin is zero Torque acting on particle about origin is Non zero

3 It is found that when waves from two identical coherent sources superpose at certain point with same individual intensity then the resultant intensity is equal to the intensity of one wave only This means that phase difference between the two waves at that point is 1 Zero 3 2 3 2 1 3 4 T

Huygens principle of secondary wavelets may not be used to 1 Find the new position of a wavefront 2 Explain Snell s law 3 Explain laws of reflection

28 An electron moving with a speed u along the positive x axis at y 0 enters a region of uniform magnetic field B B which exists to the right of y axis The electron exists from the region after some time with the speed v at co ordinate x y then A v u y 0 B V u y 0 X X x C v u y 0 D v u y 0

Two beams A and B of plane polarised light with mutually perpendicular planes of polarisation are seen through a polaroid From the position when the beam A has maximum intensity and beam B has zero intensity a rotation of polaroid through 60 makes the two beams appear equally intense If the initial intensities of the two beams are I and I 10 respectively then equals 18 1 3 2 4 3 PIN N W 2

29 A charged particle of specific charge charge mass a is released from origin at time t 0 with Z velocity V 1 i 1 in uniform magnetic field B Bi Coordinates of the particle at time Ba are A 2 Vo 2Ba aB Ba C 0 2v VA Ba 28 a B D 28 B a 0 0 2 B C

8 In a YDSE how many maxima can be obtained o screen excluding central maxima on both sides a central fringe if 2000A and d 7000A 1 12 2 6 3 18 4 9

9 A beam of unpolarised light passes through a tourmaline crystal A and then it passes through a second tourmaline crystal B oriented so that its principal is parallel to that of A The intensity of the emergent light is Now B is rotated by 45 about the ray The emergent light have intensity 3 2 11 2012 4

A trolley filled with sand moves on a smooth horizontal surface with a velocity 10 m s A small hole is made at the base of it from which sand is leaking out at constant rate As the sand leaks out Smooth surface The velocity of the trolley increases till 20 m s The velocity of the trolley decreases till it stops The velocity of the trolley remains 10 m s The sand applies a horizontal force on trolley towards right while leaking

19 A short electric dipole with dipole moment p 2qd is placed coaxially with a ring of radius R at a distance r from the center of the ring as shown in figure The flux of the electric field due to dipole through the area bounded by the ring is Ra 280 80 R 2d The product 3a is R

13 If two bulbs of power 60 W and 100 W respectively each rated 110 V are conhe of 220 V then 1 60 W bulb will fuse 3 Both bulbs will fuse 2 100 W bulb will fuse 4 Bulbs will not fuse

A block of mass 1kg is placed on a roughl horizontal surface connected by a light string passing over two smooth pulleys as shown Another block 1 kg is connected to the other end of the string The acceleration of the block on table is Coefficient of friction 0 2 P O 0 8 g 1kg 0 2 1kg

2 A soap bubble 250nm thick is illuminated by white light The index of refraction of the soap bubble is 1 36 Which wavelength is missing in range of visible light for reflected rays 1 300mm 2 600mm 3 400mm 4 680mm