A to Z Exams

In an experiment of photoelectric emission, for incident light of 4000A0, stopping potential is 2V. If the wavelength of incident light is made 3000A0, then the stopping potential will be

A capacitor of capacity C is charged to a potential V.It is charged and isolated.Then distance between the plates is halved and then half the distance between them is filled with a metal slab.Then the capacitor

The elementary particles heavier than nucleons are called

When a dielectric material is introduced between the plates of a charged condenser the  electric field between the plates:

A machine gun fires 360 bullets per minute. Each bullet moves with a velocity of 600ms-1, If the power of the gun is 5.4kw, the mass of each bullet is,

The bridge of a sonometer is slightly displaced so that the length of wire is decreased by 0.5% and tension in the wire is increased by 1%.The fundamental frequency of wire

An iron block of sides 50 cm x 8 cm x 15 cm has to be pushed along the floor. The force required will be minimum when the surface in contact with ground is:

The two surfaces of a biconvex lens has same radii of curvatures. This lens is made of glass of refractive index 1.5 and has a focal length 10 cm in air. The lens is cut into two equal halves along a plane perpendicular to its principal axis to yield two plano-convex lenses. The two pieces are glued such that the convex surfaces touch each other. If this  combination lens is immersed in water (refractive index = 4/3), its focal length (in cm) is :

A tension of 22 N is applied to a copper wire of cross-sectional area 0.02 cm2 Young’s modulus of copper is 1.1x1011 N/m2and Poisson’s ratio 0.32. The decrease in cross sectional area will be

Light wave of frequency 4x1014Hz and λ=5x10-7m passes through a medium.The refractive index μ then the focal length of lens is

The least distance of distinct vision is 25cm. If the focal length of convex lens is 10 cm. It acts as a simple microscope of maximum magnification

An iron load of 2kg is suspended in air from the free end of a sonometer wire of length 1m.A tuning fork of frequency 256Hz is in resonance with 1/√14 times the length of the sonometer wire.If the load is immersed in water,the length of the wire in meter that will be in resonance with the same tuning fork is (specific gravity of iron=8)

In youngs experiment λ=4000A0 fringes observed have a width β. The light illuminating with new λ=6000A0 and the separation between the interfering sources is halved. The ratio of the distance between the screen and the interfering sources if the fringe width remains unaltered respectively is

The objective and eyepiece of an astronomical telescope are double convex lenses with refractive index 1.5. When the telescope is adjusted to infinity, the separation between the two lenses is 16 cm. If the space between the lenses is now filled with water and again telescope is adjusted for infinity, then the present separation between the lenses is

The maximum potential that can be measured with a voltameter of resistance 1000Ω is 6V.Resistance that must be connected to measure a potential of 30V with it is

In a meter bridge a 30 Ω resistance is connected in the left gap and a pair of resistances P and Q in the right gap. Measured from the left, the balance point is 37.5 cm, when P and Q are in series and 71.4 cm when they are parallel. The values of P and Q (in Ω ) are

Two metal rods A and B of equal lengths and equal cross-sectional areas are joined end to end. The coefficients of thermal conductivities of A and B are in the ratio 2 : 3, when the free end of A is maintained at 1000C and the free end of B is maintained at 00C, the temperature of the junction is

A 4 μF capacitor is charged by a 200V battery. It is then dis-connected from the supply and is connected to another uncharged 2 μF capacitor. During the process, loss of energy (in J) is

A motor cycle starts from rest and accelerates along a straight path at 2m/s2.At the starting point of the motor cycle, there is a stationary electric siren. How far has the motor cycle gone when the driver hears the frequency of the siren at 94% of its value when the motor cycle was at rest?(speed of sound=330ms-1)

A maximum current 0.5mA can be passed through a galvanometer of resistance 20Ω.The resistance to be connected in series to convert it into voltmeter of range 0-5V is

A wire carrying a current of 4A is in the form of a circle it is necessary to have a magnetic field of induction πx10-5T at the center.The radius of the circle must be

Power radiated by a black body at temperature T1 is P and it radiates maximum energy at a wavelength λ1.If the temperature of the black body is changed from T1toT2,it radiates maximum energy at a wavelength λ1/2.The power radiated at T2 is

Two straight parallel wires carry currents of 200mA and 1A in opposite directions.If the wires are 20 cm apart,the distance of the neutral point from the 1A wire is(in cm) ±

The natural frequency of a tuning fork p is 432 Hz. 3 beats/s are produced when tuning fork P and another tuning fork Q are sounded together. If P is loaded with wax, the number of beats increases to 5 beats/s. The frequency of Q is

Two cylindrical conductors A and B of same metallic material have their diameters in the ratio 1 : 2 and lengths in the ratio 2 : 1. If the temperature difference between their ends is same, the ratio of heats conducted respectively by A and B per sec is:

The frequency of a tuning fork x is 5% greater than that of a standard fork of frequency K.The frequency of another fork y is 3% less than that of K.When x and y are vibrated together 4 beats are heard per second.The frequencies of x and y are

Two concentric circular coils A and B have radii 25cm and 15cm and carry currents 10A and 15A respectively.A has 24 turns and B has 18 turns.The direction of currents are in opposite order.The magnetic induction at the common centre of the coil is

The maximum tension a rope can withstand is 60 kg wt The ratio of maximum acceleration with which two boys of masses 20 kg and 30 kg can climb up the rope at the same time is

Two strings x and y on a Veena playing the same note are slightly out of tune and produce 6 beats per second. The tension in x is slightly decreased and it is found tha the beats fall to 3 per second. If the original frequency of x is 324 Hz, the frequency of y is

Two parallel rails of a railway track insulated from each other and with the ground are connected to a millivoltmeter. The distance between the rails is one meter. A train is traveling with a velocity of 72 km/h along the track. The reading of the milli-voltmeter (in mV) is (Vertical component of the earth'smagnetic induction is 2 x 10-5 T)

A car of mass 400 kg and travelling  at 72 kmph crashes into a truck of mass 4000 kg and travelling at 9 kmph, in the same direction. The car/bounces back at a speed of 18 kmph.The speed of truck after the impact is

A 20F capacitor is charged to 5V and isolated. It is then connected in parallel with an uncharged 30F. The decrease in the energy of the system will be

The length of an elastic string is 'a' metres when the longitudinal tension is 4 N and 'b' meters when the longitudinal tension is 5 N. The length of the string in metres when the longitudinal tension is 9 N is:

A tuning fork is in resonance with a sonometer wire. The same tuning fork produces 3 beats in 2s, when tension in the wire is increased by 2% . The frequency of wire before increasing tension is

The weight of a man in a lift moving upwards is 608 N while the weight of the same man in the lift moving downwards, with the same acceleration is 368 N. His normal weight in N is:

The equation of trajectory of a projectile is y = 10x - (5/9) x2. If we assume g =10 ms-2, the range of   projectile (in meter) is

Work done to increase the temperature of one mole of an ideal gas by 300C, if it is expanding under the condition V∝T2/3 is, (R =8.314 J/mole/0 K)

A rifle of 20 kg mass can fire 4 bullets per second. The mass of each bullet is 35 x 10-3 kg and its final velocity is 400 ms-1. Then what force must be applied on the rifle so that it does not move backwards while firing the bullets

A bullet of mass 0.02 kg travelling horizontally with velocity 250 ms_1 strikes a block of wood of mass 0.23 kg which rests on a rough horizontal surface. After the impact, the block and bullet move together and come to rest after traveling a distance of 40 m. The coefficient of sliding friction of the rough surface is

When a positively charged particle enters a uniform magnetic field with uniform velocity, its trajectory can be : 1) a straight line 2) a circle 3) a helix

Two electric charges 12 μC and -6 μC are placed 20 cm apart in air, there will be a point P at which electric potential is zero outside excluding the region between them. The distance of P from -6 μC charge is:

The third overtone produced by a vibrating string 2m long is 1200 Hz. The velocity of propagation of the wave is

One end each of a resistance r capacitor C and resistance 2r are connected together. The other ends are respectively connected to the positive terminals of batteries, P, Q, R having respectively emfs E, E and 2E. The negative terminals of the batteries are then connected together. In this circuit, with steady current the potential drop across the capacitor is ;

A wheel has a speed of 1200 revolution per minute and is made to slow down at a rate of 4 radian/sec2. The number of revolutions it makes before coming to rest is :

Under the application of force, a steel wire (Y = 19 x 1010Nm-2) of 5 m in length suffers an elongation of 1 mm. The potential energy stored per unit volume in this process, in joules per m3 is :

In Young's double slit experiment,first slit has width four times the width of the second slit, the ratio of the maximum intensity to the minimum intensity in the interference fringe system is :

The equation connecting thermo emf with the temperature difference between the junctions 't' of a thermocouple, whose cold junction is maintained at 00C, is given by e = 2040 t - 6.2 t2. The neutral and inversion temperatures of the thermocouple in C .ire respectively and nearly equal to:

200MeV energy is released when one nucleus of 235U undergoes fission. The number of fissions per second required for producing a power of 1 megawatt

A 4μF capacitor is charged by a 200V battery.It is then disconnected from the supply and is connected to another uncharged 2μF capacitor.During this process,Loss of energy(in J)is

The charge stored in a capacitor is 20μC and the potential difference across the plates is 500V,its capacity is

An auditorium has volume of 105m3 and surface area of absorption 2 x 104m2.Its average absorption coefficient is 0.2 .The reverberation time of the auditorium in seconds is

Two long straight conductors are held parallel to each other at a distance 0.3m.If the conductors carry currents 2A and 8A in opposite directions,the distance of the neutral point from the conductor carrying smaller current is

An infinitely long thin straight wire has uniform linear charge density of 1/3 coul.m-1.Then the magnitude of the electric intensity at a point 18 cm away is

Two small angled prisms A and B deviate the blue rays by 70 and 90 and the red rays by 50 and 70 respectively. The prism which has a greater dispersive power is

A north pole of strength πAm, is moved around a circle or radius 10 cm which lies around a straight conductor carrying a current of 10 A. The work done is nearly

Two vibrating tuning forks produce vibrations at the tympanic of an observer represented by y1=4sin(260 πt) and y2=4sin(256 πt).The number of beats heard by the observer in one minute is

Two sources A and B are sending notes of frequency 680 Hz. A listener moves from A to B with a constant velocity V. If the speed of sound in air is 340 ms-1, what must be the value of V so that he hears 10 beats per second

While a collector to emitter voltage is constant in a transistor, the collector current changes by 8.2 mA. When the emitter current changes by 8.3 mA. The value of forward current ratio is:

A 2 MeV proton is moving perpendicular to a uniform magnetic field of 2.5 tesla. The force on the proton is (mass of proton = 1.6 x 10-27 kg)

Match the appropriate pairs from Lists I and II: List-I List-II 1.NItrogen molecules A.continuous spectrum 2.Incandescent solids B.Absorption spectrum 3.Fraunhoffer lines C.Band spectrum 4.Electric arc between iron rods D.Emission spectrum

The frequency of a tuning fork x is 5% greater than that of standard fork of frequency K.The frequency of another fork y is 3% less than that of K.When x and y are vibrated together 4 beats are heard per second.The frequencies of x and y are

Three condensers 1μF,2μF and 3μF are connected in series to a p.d of 330volt.The PD across the plates of 3μF is

A cell of emf 2V and negligible resistance is connected in series with a resistance of 5 Ω, and a potentiometer wire of resistance 10 ohm. What is the potential drop per cm if the length of the potentiometer wire is 10 m. The emf a cell which is balanced by 750 cm long wire is

Which of the following is more effective in inducing nuclear fission ?

In n-p-n transistor, in CE configuration:(1)  The emitter is heavily doped than the collector.(2)  Emitter and collector can be interchanged.(3)  The base region is very thin but is heavily doped.(4)  The conventional current flows from base to emitter

An insulated cylindrical vessel filled with an insulated piston of negligible weight and negligible thickness at the midpoint of the vessel. The cylinder contains a gas at 0oC. When the gas is heated to 100oC, the piston moves through a length of 5 cm. Length of the cylindrical vessel in cm is

A train is moving towards north with a speed of 180 kilometers per hour. If the vertical component of the earths magnetic field is 0.2x10-4T, the emf induced in the axle of length 1.5m is

Two trains are approaching each other on parallel tracks with same velocity.The whistle sound produced by one train is heard by a passenger in another train.If actual frequency of whistle is 620Hz and apparent increase its frequency is 100Hz,the velocity of one of the two trains is(Velocity of sound in air=335ms-1)

Two long straight conductors are held parallel to each other at a distance 0.3 m. If the conductors carry currents 2A and 8A in opposite directions, the distance of the neutral point from the conductor carrying smaller current is:

The velocity of propagation of sound is 330 m/s, in air. If the third harmonic of the fundamental that can be exerted in an open ended tube is 450 Hz, the length of the tube is :

A galvanometer of resistance 20Ω is to be shunted so that only 1% of the current passes through it.shunt connected is

Fraunhofer lines are produced by the absorption of light in :

A bullet of mass 10 g is fired horizontally with a velocity 1000ms-1 from a rifle situated at a height 50 m above the ground. If the bullet reaches the ground with a velocity 500ms-1, the work done against air resistance in the trajectory of the bullet is : (g=10ms-2)

When a liquid in a glass vessel, is heated its apparent expansion is 10.30 x 10-4same liquid when heated in a metal its apparent expansion 10.06 x 10-4/0C. The coefficient of linear expansion of the metal is : (coefficient of linear expansion of glass = 9 x 10-6/0C):

Two wires A and B are of lengths 40 cm and 30 cm, A is bent into a circle of radius r and B into an arc of radius r. A current i1 passed.through A and i2 through B. To have the same magnetic inductions at the centre, the ratio of    i1  :   i2  is

When a vibrating tuning fork is placed on a sound box of a sonometer, 8 beats per second are heard when the length of the sonometer wire is kept at 101 cm or 100 cm. Then the frequency of the tuning fork is (consider that the tension in the wire is kept constant)

A long straight wire carries an electric current of 2A.The magnetic induction at a perpendicular distance of 5m from the wire is (μ0=4πx10-7 Hm-1)

Along the x-axis, three charges q/2 , -q and q/2 are placed at x = 0, x = a and x = 2a respectively. The resultant electric potential at a point P located at a distance r from the charge -q ( a << r ) is ( εo is the permittivity of free space )

An observer is moving away from a sound source of frequency 100Hz. If the observer is moving with a velocity 49m/s and the speed of sound in air is 330m/s. The observed frequency is:

A galvanometer of resistance 100Ω gives full scale deflection with 5mA current.To convert it into a 5 volt range voltmeter,the value of resistance connected in series is

A body of mass m is suspended to an ideal spring of force constant k. The expected change in the position of the body due to an additional force F acting vertically downwards is

The focal length of a lens of dispersive power 0.45 which should be placed in contact with a convex lens of focal length 84 cm and dispersive power 0.21 to make the achromatic combination from the two lenses, in cm is

The potential energy of a proton is 3.2x10-18J at a particular point. The electric potential at this point is

A bucket filled with water is tied to a rope of length 0.5 m and is rotated in a circular path in vertical plane. The least velocity it should have at the lowest point of circle so that water doesnot spill is, (g = 10 ms-2 )

The length of a narrow closed pipe is L.The possible wavelengths of stationary waves forms in it are

A tuning fork A of frequency 384Hz produces 3 beats/second when sounded with a second tuning fork B of unknown frequency.When A is filed a little,the number of beats decreased to 2beats/second.The frequency of the fork B must be

When a wave travels in a medium the particles displacement is given by the equation y(x,t) = 0.03 sin π(2t - 0.01 x) where y and x are in metres and t in seconds. The wavelength of the wave is :

A body of mass m1 moving with a velocity 10 ms-1 collides with another body at rest of mass m2 After collision the velocities of the two bodies are 2 ms-1 and 5 ms-1respectively, along the direction of motion of m1.The ratio m1/ m2

Two unit negative charges are placed on a straight line. A positive charge q is placed exactly at the mid point between these unit charges. If the system of these three charges is in equilibrium, the value of q (inC) is

Eight spherical rain drops of the same mass and radius are falling down with a terminal speed of 6 cm-s-1. If they coalesce to form one big drop, what will be the terminal speed of bigger drop (Neglect the buoyancy of the air)

16 tuning forks are arranged in increasing order of frequency.Any two consecutive tuning forks when sounded together produce 8 beats per second.If the frequency of the last tuning fork is twice that of the first the frequency of the last tuning fork is

Two charges of 50 μC and 100 μC are separated by a distance of 0.6m. The intensity of electric field at a point midway between them is

In a full wave rectifier output is taken across a load resistor of 800ohm.If the resistance of diode in forward biased condition is 200 ohm,the efficiency of reflection of rectification of ac power into dc power is

In a prism, the effective indices of different colors are μv=1.6;μR=1.52;μr=1.56.The dispersive power of the prism is

Two tuning forks of frequencies 250 and 256 Hz produce beats.If maximum is produced now,thus the minimum time after which minimum is produced at that same place

A wire carrying a current of 140 ampere is bent into the form of a circle of radius 6cm.The flux density at a distance of 8 cm on the axis passing through the centre of the coil and perpendicular to its plane is(in wb/m2(approximately))

In a compensated pendulum two rods of  different metals are used with their lengths in ratio of 2 : 3. The coefficients of linear expansions for metals in the ratio is :

A flask is filled with 1.3 g of an ideal gas at 270C and its temperature is raised to 520C The mass of the gas that has to be released to maintain the temperature of the gas in the flask at 520C and the pressure remaining the same is

A transformer steps up an A.C. voltage from 230V to 2300V. If the number of turns in the secondary coil is 1000, the number of turns in the primary coil will be

Two organ(open)pipes of lengths 50cm and 51cm produce 6 beats/s.Then the speed of sound is nearly