# Physics Questions

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Physics
Basic Physics
Problem 6 Two speakers separated by a distance of 3 30m both pointing towards a wall in front of them A person standing against the wall between the speakers Position A hears destructive interference If the observer hears constructive interference after moving 0 80 m to one side of the wall what is the frequency emitted by the speaker Assume the air velocity is 343 m s
Physics
Newton's law of motion
A boy throws a ball vertically upwards then O work is done by the boy only at the moment he throws the ball O work done by boy on it is zero O work is done by the boy throughout the motion of the ball O work is done by the boy only during upward motion of the ball
Physics
Electric Field and Potential
Three concentric spherical shells have radii a and c a b c and have surface charg densities o o and o respectively If V V and Vc denote the potential of the three shells the for c a b we have A 1 Vc V VB 2 Vc VB VA V V
Physics
Magnetic Field due to current
A long rectangular loop of width w mass M and resistance R is at rest with the plane of the loop parallel to the ground Immediately to the left of the loop is a region of uniform magnetic field B that points into the screen At time t 0 a constant force F pushes the loop to the left into the magnetic field region as shown in the figure Derive an expression for the speed u of the loop immediately after it enters the magnetic field region in terms of the given variables and the time t U M Ft Bw B 0 0 8 0 0 W
Physics
Basic Physics
Tangential acceleration of a particle moving on a circular path of radius 1 m varies with time as shown The time after which total acceleration makes an angle of 45 with the velocity of particle is particle starts from rest a m s 1 4 s 1 43 S S LS S 60 2 t s 4 1 4 3 S 2 3 S
Physics
Electromagnetic waves
A 60 kg model rocket lifts off by expelling fuel downward at a rate of k 4 75 kg s for 7 s The fuel leaves the end of the rocket with an exhaust velocity of b 100 m s Let m t be the mass of the rocket at time t From the law of conservation of momentum the following differential equation for the rocket s velocity u t in meters per second is obtained m t v t 9 8m t b dm 7 dt Compute the rocket s velocity at rocket burnout after 7 s Use decimal notation Give your answer to three decimal places m s
Physics
Basic Physics
If an electromagnetic wave has a frequency of 1 46 x 1012 Hertz calculate the wavelength in meters Enter the answer using scientific notation Spaces are not allowed For example if the answer is 1 23 x 107 enter it as 1 2367 And if the answer is 4 56 x 108 enter it as 4 56e 8 Give the answer to three significant figures
Physics
Geometrical Optics
How much water should be filled in a container 21 cm in height so that it appears half filled when viewed from the top of container Given that Hwater 4 3 8 cm 10 5 cm 12 cm 16 cm
Physics
Simple harmonic motion
About its vertical axis a smooth horizontal circular table is given an angular speed A groove is made on the surface along a radius A particle is gently placed inside the grove at a distance from the centre The speed of a 2 the particle w rt table when its distance from the centre is x is Ow a O O 25 1 0 2
Physics
Circular Motion
13 In the diagram shown all the velocities are given with respect to earth What is the relative velocity of the image in mirror 1 with respect to the image in the mirror 2 The mirror 1 forms an angle with the vertical A 2v sin2 C 2v sin2 B 2vsin D None of these Mirror 1 I Object Mirror 2
Physics
Basic Physics
1 The dispersive powers of crown and filint glasses are 0 02 and 0 04 respectively In an achromatic combination of lenses the focal length of flint glass lens is 40 cm The focal length of crown glass lens will be a 20cm c 10cm b 20cm d 10cm
Physics
Geometrical Optics
The first few electronic energy states for neutral copper atom Z 29 are given as E E E where E being the ground electronic state The states E and E are doubly degenerate due to spin splitting Write the electron configuration of the states and arrange the spectral terms of the split levels following Hund s rules Explain why E E
Physics
Properties of matter
For the metal console beam in Figure 9 replace the moment and the two forces applied by a moment equivalent and the resultant of the two forces at point A A y 1 5 m L x 500 N m 3 0 5 m 2 kN 70 1 2 kN 10 15 m 0 15 m
Physics
Kinematics
A child drops a toy at rest from a point 3 0 m above the ground at the same instant her friend throws a ball upward at 6 8 m s from a point 1 0 m above the ground At what distance above the ground do the ball and the toy cross paths
Physics
Simple harmonic motion
4 Which one of the following statements is true for the speed and the acceleration a of a particle executing simple harmonic motion A Value of a is zero whatever may be the value of v B When u is zero a is zero C When u is maximum a is zero D When v is maximum a is maximum ICR SE 2004
Physics
Capacitors
A parallel plate capacitor is half filled with water in vertical direction Waters permitivity is 1 3 times higher than air What is the capacitance in UF if the plates are square with side 8m and 3mm apart eo 8 84 10 12C V m
Physics
Kinematics
A 17th century scientist Galileo observed that for frictionless surfaces X and Y a ball released from the top reaches the top on the other side If Z is also a frictionless horizontal surface how far would a ball roll when released from the top of the inclined surface 1 h X 2 2h h h Z 3 It will never stop 4 3h
Physics
Basic Physics
A particle is in an infinite square well potential with walls at x 0 and x L If the particle is in the state y x Asin 7 Where A is a constant Find the probability that the particle is in between x L 3 an x 2L 3 upto 2 decimal places
Physics
Basic Physics
A pipe R can fill a tank in 45 minutes Two leakages P and Q empty the already filled tank in 90 minutes and 180 minutes respectively How long will it take to fill the tank if pipes P and Q are left open with pipe R O O O 3 hours 4 hours 5 hours 6 hours
Physics
Basic Physics
3 11 A 250 g ball is launched with a speed of 35 m s at a 30 angle A strong headwind exerts a the wind constant horizontal drag force on the ball What is the magnitude of the drag force reduces the ball s travel distance by 20
Physics
Basic Physics
The blocks MP 2 2 kg and MQ are connected by an inextensible rope passing over a frictionless pulley as illustrated in Figure 2 Initially the block MP is supported and therefore no block moves The coefficient of friction between the MP block and the horizontal surface is 0 40 When MP is released the blocks move with an acceleration of 0 50 m s2 Find the value of MQ MP
Physics
Electric Field and Potential
length is included in a circuit as shown in figure Given are the emf of the current source its internal resistance r and the distance d between the plates An electron with a velocity u flies into the capacitor so that the electron flies out of the capacitor at an angle of 37 to the plates Find the value of Rin ohm Assume that circuit is in steady state and neglect relativistic effect Take 91 cm 3 V r 2 Q d mm u 4 x 107 m s m 9 1 x 10 1 kg and e 1 6 x 107 19 C ax A d yg a2 l T Fuka h fa zefy xguz qkqy umfa 6 1 ua zata g fa a 3 R qu 54 dkg ufadu a tar 1 v ia uka 34 GR na Geal fc s azia cu uz mka agz Aga jy g fukuu zum udfg u aya ch aqvq 817 9 91 cm 3 V r 2 Q d mm u 4 107 m s me 31 19 9 1 x 107 kg e 1 6 x 107 C E d www Correct Answer 10
Physics
Basic Physics
Problem 127 A cannon with bullets of total mass Mo is kept on a rough horizontal surface The coefficient of friction between the cannon and the surface is u If the cannon fires bullets with constant frequency with a relative velocity u find the velocity of the cannon when its mass with remaining bullets become M after time t Initially cannon was at rest Assume that the thrust force is greater than the limiting friction right from the beginning Mo cannon
Physics
Work, power & energy
A block of mass 2 kg is tied to elastic thread of unscratched length 2 m and suspended to point O initially block is horizontal level to this point O Now block is released and its speed is 5 m s when thread is vertical If the acceleration of the block at the lowest position is K Find the value of K 4m 2m angz W
Physics
Basic Physics
12 Two fixed frictionless inclined planes making an angle 30 and 60 with the horizontal as shown in the figure Two blocks A and B are placed on the two planes What is the relative vertical acceleration of A with respect to B A B 60 1 4 9 m s in vertical direction 2 4 9 m s in horizontal direction 3 9 8 m s2 in vertical direction 4 Zero 30
Physics
Magnetic Field
Direction of induced current in a conductor moving in a magnetic field is given by Fleming s Right hand rule In this rule middle finger and fore finger point in the direction of 1 Magnetic field and motion of conductor respectively 2 Induced current and motion of conductor respectively 3 Induced current and magnetic field respectively 4 Magnetic field and induced current respectively
Physics
X-Rays
Assume that light of wavelength 600 nm is coming from a star The limit of resolution of telescope whose objective has a diameter of 2 m is 1 83 10 7 rad 7 32 x 10 7 rad 1 2 3 4 6 00 10 7 rad 3 66 10 7 rad R P 9 1 221 7 2x107
Physics
Kinematics
Two particles A and B move in x y plane such that they have constant acceleration a 10 m s and a 5jm s respectively The velocities of particles at t 0 are 57 20 m s and Ug 2 5i 10 m s At time t 0 particle A is at origin and particle B is at point having coordinates 5 m 0 Find the instant of time in seconds at which angle between velocity of A and velocity of B is 180
Physics
Thermal Expansion
liquid w The coefficient of apparent expansion of a determined using two different vessels A and B are 7 Y2 respectively If the coefficient of linear expansion of vessel A is a the coefficient of linear expansion of the ve EAMCET 2000 B is a c ay1 2 71 72 71 72 a 3 b d 71 72 2a 71 72 3 a
Physics
Current Electricity
A potentiometer having a wire of length 10 m and resistance 20 Q is connected to an accumulator of e m f E through a resistance box When the resistance in the box is 20 a null point is observed at 5 m for a cell of e m f E The ratio of E to E is A 1 4 C 3 1 B LD 2 1 4 1
Physics
Rotation
A 500 0 g bird is flying horizontally at 2 50 m s not paying much attention when it suddenly flies into a stationary vertical bar hitting it 25 0 cm below the top Figure 1 The bar is uniform 0 800 m long has a mass of 2 50 kg kg and is hinged at its base The collision stuns the bird so that it just drops to the ground afterward but soon recovers to fly happily away Figure Bird 25 0 cm 1 of 1 Part A What is the angular velocity of the bar just after it is hit by the bird Express your answer in radians per second V AEO Submit Part B Constants Request Answer BAVE What is the angular velocity of the bar just as it reaches the ground Express your answer in radians per second rad s
Physics
Basic Physics
3 If any how speed of light in vacuum becomes 1 5 times its initial speed then new value of light year in kilometers is 1 1 11 x 10 3 km 3 1 31 x 1013 km 4 1 41 x 1013 km 2 1 21 x 10 3 km
Physics
Nucleus
In a Stern Gerlach experiment the magnetic field is in z direction A particle comes out of this experiment in 21 state Which of the following statements is true a The particle has a definite value of the y component of the spin angular momentum b The particle has a definite value of the square of the spin angular momentum c The particle has a definite value of the x components of spin angular momentum d The particle has definite values ofx and y components of spin angular momentum
Physics
Basic Physics
In the figure shown AB is a light ray incident on the face PS of a glass slab at an angle i 0 Given face PQ is silvered then the emergent ray D deviates by an angle C P A 20 Oc a 9
Physics
Friction
base length l and height h on an irregular surface as shown Then the minimum coefficient of friction between the chain and the surface must be equal to n h O Find n 0 25 0 5
Physics
Work, power & energy
The elevator E has a mass of 3000 kg when fully loaded and is connected as shown to a counterweight W of mass 1000 kg Determine the power in kilowatts delivered by the motor a when the elevator is moving down at a constant speed of 3 m s b when it has an upward velocity of 3 m s and a deceleration of 0 5 m s
Physics
Basic Physics
How much water overflows when a Pyrex vessel filled to the brim with 1 L of water at 25 C is heated to 194 F The coefficient of volume of expansion of Pyrex and water are 9 x 10 6 C and 2 1 x 10 1 C respectively
Physics
Basic Physics
In the loops shown in Fig all curved sections are either semicircles or quarter circles All the loops carry same current The magnetic fields at the centres have magnitudes B B B and B Then D Q B b 1 B B B B 2 B B B B3 3 B4 B B B3 4 B B B3 B
Physics
Optical Instruments
Question 11 An object is moving parallel to the principal axis of a concave mirror at some height as shown in the figure For the given location of the object and image the direction of motion of image will be directed along object image DA St line I B St line 2 c St line 3 D St line 4
Physics
Gravitation
If three particles each of mass M are placed at the three corners of an equilateral triangle of side a the net force exerted by this system on another particle of mass M placed at the mid point of any one side is 1 4GM 22 2 3GM 2 3 3GM 2 4 0
Physics
Thermodynamics
Find the temperature at which the pressure attained by the ideal gas is minimum in the process given by the equation a T To V where To and a 2 are positive constants and V is the volume of one mole of an ideal gas O O 7To 2 2To 3 3To 2
Physics
Basic Physics
23 A 1000 resistance and a capacitor of 1000 reactance are connected in series across a 220V source The peak value of the displacement current is 1 4A 2 11 2A 3 2 2A M
Physics
Circular Motion
A ball attached to an end of a string is released from horizontal position as shown For what value of angle between string and vertical during its motion the total acceleration is directed horizontally 90 O O O 90 sin
Physics
Experiments
216 To compare the emfs of two primary cells and e in the given circuit of potentiometer first balance point is obtained for E cell in the circuit only for length 1 x 1 1 Now balance point obtained again for the cell of emf only for length 12 B x 1 From Eqs i and ii 12 1 In the figure a long uniform potentiometer wire AB is having a constant potential gradient along its length The null points of the two primary cells of emfs and E connected in the manner shown are obtained at a distance of 120 cm and 300 cm from the end A E The value of will be 62
Physics
Capacitors
5 A parallel plate capacitor consists of two circular plates each of radius 2 cm separated by distance question 0 1 m If voltage across the plate is varying at of 5 x 1013 V s then value of displacement current is 7 60 A 3 5 56 A 2 5 56 10 A 4 2 28 x 10 A
Physics
Work, power & energy
A 50 kg man with 20 kg load on his head climbs up 20 steps of 0 25 m height each Then the work done against gravity in climbing is take g 10 m s 2 350 J 1 5 J 3 100 J 4 3500 J If any how speed of light in vacuum becomes 1 5 times its initial speed then new value of light year
Physics
Basic Physics
The e m f E of the battery is balanced by p d across 75 cm of a potentiometer wire For a standard cell of e m f 1 02 V the balancing length is 50 cm The value of E is A 0 68 V 1 53 V B D 1 24 V 1 08 V
Physics
Basic Physics
39 A block of mass m is connected with a string which is wounded over a disc of mass 2m and radius R as shown in the figure If the system is released from rest then accelerations of the block will be 2m R 1 3 614 2 m 2 4 2g 3 3g 4
Physics
Kinematics
After starting from rest a body travels a distance of 3S with uniform acceleration then moves with uniform velocity for a distance of 2S and finally comes to rest after moving further 5S under uniform retardation What is the ratio of average velocity to maximum velocity O O 74 5 9 3 7 9
Physics
Electric Field and Potential
Consider a square loop of wire of side length 1 lying in the xy plane as shown in figure Suppose a particle of charge q is moving with velocity v where v c in the xz plane at a constant distance zo from xy plane Assume the particle is moving in the positive x direction Suppose the particle crosses the z axis at t 0 Give the induced emf in the loop as a function of time