A to Z Exams

A block of mass 10kg lying on a smooth horizontal surface is being pulled by means of a rope of mass 2kg.If a force of 36N is applied at the end of the rope. The tension at the midpoint of the rope is

When an air bubble of radius r rises from the bottom to the surface of a lake. Its radius becomes 5r/4 (the pressure of the atmosphere is equal to the 10 m height to water column). If the temperature is constant and the surface tension is neglected the depth of the lake is

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

When an air column of length ‘l’ open at both ends vibrates in its fundamental note, the wavelength is given by

If the magnitude of the intensity of a magnetic field at a distance x on the axial line and at a distance y on the equatorial line of a given dipole have the same value the ratio x : y is :

In Sun, the important source of energy is

A pyknometer weight 40 g when empty and 1040 g when filled with mercury at 00C On heating to 1000C, 10 g of mercury overflows. If the coefficient of real expansion of mercury is 0.00020C the coefficient of expansion of glass is :

Two cylinders A and B fitted with pistons, contain equal number of moles of an ideal mono atomic gas at 400 K. The piston of A is free to move while that of B is held fixed. Same amount of heat energy is given to the gas in each cylinder. If the rise in temperature of the gas in A is 42 K, the rise in temperature of thegas in B is (γ = 5/3)

Capacitance of a capacitor becomes 7/6 times its original value if a dielectric slab of thickness,t=2/3d is introduced in between the plates.d is the separation between the plates.The dielectric constant of the di-electric slab is

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

Which one of the following statement is true ?

When a monochromatic light of frequency v is incident on a metal, stopping potential is V0. Frequency of the incident light for which stopping potential becomes 2V0 is

There are two holes one each along the opposite sides of a wide rectangular tank. The cross section of each hole is 0.01 m2and the vertical distance between the holes is one meter. The tank is filled with water. The net force on the tank in newton when the water flows out of the holes is: ( Density of water = 1000 kg/m3 )

The force acting on a charge of 10-10C placed in an electric field of intensity 600 V/m is

A Tuning fork A produces 6 beats per second with another fork B.On loading B with a little wax,it produces 5 beats per second with A if the frequency of A is 256Hz,the frequency of B is

When cold junction is at 00C variation of thermo emf(e) of Fe-Cu thermo couple with temperature of hot junction t is given as e=14t-0.02t2.Its neutral temperature is

The coils A and B having the radii in the ratio 1:2 carrying currents in the ratio 5:1 and have the number of turns in the ratio 1:5.The ratio of magnetic inductions at their centres is

Two progressive waves each of frequency 10Hz traveling at 20cms-1 are superposed.In the resulting stationary wave,the distance between the successive nodes is

The wave length of the Kαline for an element of atomic number 43 is λ.Then the wavelength of the Kαline for an element of atomic number 29,is

A simple microscope is rated 5x for a normal relaxed eye.what will be its magnifying power for a far sighted man whose near point is 40 cm.

A thin prism of 40 angle gives a deviation of 2.40. The value of refractive index of the material of the prism is

A sphere of radius 1m encloses a charge of 5μC. Another charge of -5μC is placed inside the sphere. The net electric flux would be

Two unknown resistance X and Y are connected to left and right gaps of a meter bridge and the balancing point is obtained at 80 cm from left. When a 10Ω resistance is connected in parallel to X, the balance point is 50 cm from left. The values of X and Y respectively are

A man stands infront of a hill rock and fires a gun. He hears an echo after 1.5 sec. the distance of the hill rock form the man is (velocity of sound in air = 330m/s)

A light of length 75 cm is suspended from the ceiling horizontally by means of two vertical wires of equal length tied to its ends. One of the wires is made of steel of cross section 0.2 sq cm.The Position along the rod at which a weight may be hung to produce equal stresses.ysteel=20x1010 N/m2,Ybrass=10x1010N/m2

The frequency of a fork is 500 Hz.Velocity of sound in air is 350ms-1.The distance through which sound travel by the time the fork makes 125 vibrations is

A proton is projected with a velocity 107ms-1 ,at right angles to a uniform magnetic field of induction 100mT.The time(in seconds)taken by the proton to traverse 900 arc is:(Mass of proton=1.65x10-27kg and charge of proton = 1.6x10-19C

Two waves of wavelengths 2m and 2.02m respectively moving with the same velocity superpose to produce 2 beats/s.The velocity of the wave is

The ratio of specific heats of a gas is γ.The change in internal energy of one mole of the gas, when the volume changes from V to 2V at constant pressure P is

The spheres of different materials one with double the radius and one-fourth wall thickness of the other are filled with ice.If the time taken for complete melting of ice in the larger radius one is 25 minutes and that for smaller one is 25 minutes,the ratio of thermal conductivities of materials of larger sphere to smaller sphere is:

Electric charges of 1μC, 1 μC and 2 μC are placed in air at the corners of A, B and C respectively of an equilateral triangle ABC having the length of the side 10 cm.The resultant force at C is (1/(4πε0 = 9 x 109 N-m2/ c2

Un polarized light of intensity I0 is incident on a polarizer and the emerging light strikes a second polarizing filter with its axis at 450 to that of the first.The intensity of the emerging beam

The rate constant of the reaction at temperature 200K is 10 times than the rate constant at 400K.The activation energy of the reaction is

A train is travelling at 120 Kmph and blows a whistle of frequency 1000Hz.The frequency of the note heard by a stationary observer if the train is approaching him and moving away from him are (Velocity of sound in air =330 ms-1)nearly

A transistor having a β equal to 80 has a change in base current of 250μA,then the change in collector current is :

When a liquid is heated in copper vessel its Coefficient of apparent expansion is 6x10-6/0C.When the same liquid is heated in a steel vessel its coefficient of apparent expansion is 24x10-6/0C If coefficient of linear expansion for copper is 18x10-6/0C the coefficient of linear expansion for steel is

In Young’s double slit experiment,the intensity at appoint P on the screen is half the maximum intensity in the interference pattern.If the wavelength of light used is λ and d is the distance between the slits, the angular separation between point P and the center of the screen is

When a high resistance R is connected in series with a voltmeter of resistance G, the range of the voltmeter increases 5 times. Then G:R will be

Magnetic field induction at the centre of a circular coil of radius 5 cm and carrying a current 0.9 A is (in S.I. units) (ε0 = absolute permittivity of air in S.I. units; velocity of light = 3 x 108 ms-1)

Photons of energy 2.0 eV and wavelength λ fall on a metal plate and release photoelectrons with a maximum velocity v.By decreasing X by 25% the maximum velocity of photoelectrons is doubled. The work function of the material of the metal plate,in eV 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 clock pendulum made of invar has a period of 0.5 s , at 200 C . If the clock is used in a climate where the temperature averages to 300 C how much time does the clock loose in each oscillation (for invar α = 9 x 10-70 C and g = constant

The frequency of a tuning fork A is 2% greater than that of standard fork K.The frequency of another tuning fork B is 3% less than K.When A and B are vibrated together 6 beats per second are heard per second. The frequencies of A and B are

Two strings of the same material and the same area of cross-section ae used in sonometre experiment.One is loaded with 12kg and the other with 3kg,the fundamental frequency of the first string is equal to the overtone of the second string.If the length of the second string is 100cm,then the length of the first string is

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 motor of power P0 is used to deliver water at a certain rate through a given horizontal pipe. To increase the rate of flow of water through the same pipe n times, the power of the motor is increased to P1 The ratio of P1 to P0 is

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

An ammeter whose resistance is 180 Ω shows full scale deflection when the current is 2mA.The shunt required to convert into an ammeter reading 20 mA is (in ohm)

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

Two charges 8C and -6C are placed at a distance of separation d between them and exerts a force of magnitude  F on each other. If a charge 8C is added to each of these and they are brought nearer to by a distance d/3, the magnitude of force between them

A certain block weights 15N in air. But it weighs only 12N when completely immersed in water. When immersed in another liquid, it weighs 13N. The ratio of relative density of the block and the liquid

Indium impurity in germanium makes it into a

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

Charges +50,+20,+30 and -100 nano coulomb are placed at the four corners of a square of side 5√2cm.The potential at the intersection point of diagonals is

A wave of frequency 500Hz has a velocity of 360ms-1,what is the distance between two nearest points 600 out of phase?

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

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 ball is projected vertically down with an initial velocity from a height of 20 m on to a horizontal floor. During the impact it loses 50% of the energy and rebounds to the same height, the initial velocity of its projection is :

Degenerate electron pressure will not be sufficient to prevent core collapse of 'white dwarf' if its mass becomes n times of solar mass. Value of n is:

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)

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

A charged particle of mass 3 x 10-6 held stationary in spacing in an electric field of strength 106 NC-1 directed vertically downwards. The charge on the particle is :

A wire of length 1m and negligible mass is fixed at one end ,and a sphere attached to it at the other end.The sphere is projected horizontally with velocity√90ms-1 and it describes a vertical circle. The elongation in the wire when the sphere is at the top position is e.Now the elongation in the wire when the sphere is at bottom position is(g=10ms-2),the stress in the wire at bottom position is within elastic limit)

If the focal length of a lens for marginal rays and paraxial rays are 12.5cm and 13cn respectively, the longitudinal spherical aberration is

Consider the following statements A and B and identify the correct answer :(A) : In an elastic collision, if a body suffers a head on collision with another of same mass atrest, the first body comes to rest while the other starts moving with the velocity of the first one.(B) : Two bodies of equal mass suffering a head on elastic collision merely exchanges their velcities :

In a potentiometer experiment, when a resistance of 10 ohm is connected in parallel to the cell in secondary circuit , the balancing length is 350 cm. when 10 ohm resistance is replaced by 20 ohm resistance, the balancing length becomes 420 cm.The internal resistance of the cell in secondary circuit is

A coil of radius π meters,100 turns carries a current of 3A.The magnetic induction at a point on its axis at a distance equal to √3 times its radius from its centre is

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

If the work done in stretching a wire by 1mm is 2J,the work necessary for stretching another wire of same material but with double radius of cross-section and half the length by 1mm(in joule) is:

If in a Wheatstone bridge the battery and Galvanometer are interchanged, the condition for balance

Calculate enthalpy for formation of ethylene from the following dataI. C(graphite)  + O2(g) ----->  CO2(g)   ∆H = 393.5kjII. H2(g) + (1/2) O2(g) ---------->  H2O(l) ∆H = -286.2kjIII.C2H4(g) + 3O2(g) ----------> 2CO2(g) + 2H2O(l)   ∆H = -1410.8kj

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

The radii and Young's moduli of two uniform wires A and B are in the ratio 2 : 1 and 1 : 2 respectively. Both wires are subjected to the same longitudinal force. If the increase in length of the wire A is one percent the percentage increase in length of the wire B is

In a parallel plate air capacitor of capacitance 4 farad, if the lower half of air space is filled with a material of dielectric constant 3 its capacitance changes to

A cylindrical resonance tube open at both ends has a fundamental frequency “f’ in air.If half of the length is dipped vertically in water,the fundamental frequency of the air column will be

The magnetic induction at point 1cm away from a straight long current carrying Conductor is found to be 1x10-5wb/m2.the current that is passing through the conductor is

Two tuning forks A and B give beats per second.A resonates with a closed column in air 15 cm long and B with an open column 30.5 cm long in their fundamental harmonics.Their frequencies are

In a p-n junction the depletion region is 400nm wide and electric field of 5x105Vm-1 exists in it. The minimum energy of a conduction electron, which can diffuse from n-side to the p-side is

Two identical metal spheres possess +60C and -20C of charges.They are brought in contacts and then separated by 10cm.The force between them is

For an electron in H-atom the frequency of photon for transition between levels 1 and 2 is V .The photon frequency for transition between levels 2 and 3 is closest to

The angle of minimum deviation when light is incident at an angle of 450 on the refracting faces of an equilateral prism of refractive index 1.414 is

At least how many thermal neutrons should be available to start a fission reaction

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)

A liquid of mass ‘m’ and specific heat C is heated to a temperature 2T.Anither liquid of mass m/2 and specific heat 2C is heated to a a temperature T.If these two liquids are mixed,the resulting temperature of mixture is

A somometer wire vibrates with frequency of 500 Hz when the tension is T1 and with a frequency of 400 Hz when the tension is T2.Its frequency of vibration for a tension(T1-T2) is (in Hz)

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 large tank filled with water to a height h is to be emptied through a small hole at the bottom The ratio of times taken for the level of water to fall from h to h/2 and h/2 to zero is

A potentiometer wire of length 100 cm has a resistance of 10 Ω. It is connected in series with a resistance and a cell of emf 2V and of negligible internal resistance. A source of emf 10 mV is balanced against a length of 40 cm of the potentiometer wire. The value of external resistance is:

The coil in a MCG has an area of 4cm2 and 500 turns.The intensity of magnetic induction is 2T.when a current of 10-4A is passed through it,the deflection is 200.The couple per unit twist is(N-m)

A car travels the first half of a distance between two places a speed of 30 km/hr and the second half of the distance a 50km/hr. The average speed of the car for the whole journey is

The distances between the objective and the eye lens of an astronomical telescope when adjusted for parallel light is 100cm.The measured value of the magnification is 19.The focal length of objective and eye piece are

The relation between the coefficient of real expansion (γr) and coefficient of apparent expansion (γa) of a liquid and the coefficient of linear expansion (αg) of the material of the container is

When a wire of length 10 m is subjected to a force of 100 N along its length, the lateral strain produced is 0.01 x 10-3 m. The Poisson's ratio was found to be 0.4. if the area of cross-section of wire is 0.025 m2, its Young's modulus is

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 stretched uniform wire under tension is in resonance with the fundamental frequency of a closed tube.If the tension in the wire is increased by 8N, it is in resonance with first overtone of the closed tube.The initial tension in the wire is

A potentiometer having wire of 4m length is connected to the terminals of a battery with a steady voltage.A leclanche cell has a null points at 1m,If the length of the potentiometer wire is increased by 1m,the position of the null points is

In the Young's double slit experiment, the intensities at two points P1, and P2 on the screen are respectively I1, and I2. If P1, is located at the centre of a bright fringe and P2 is located at a distance equal to a quarter of fringe width from P1 then I1/I2 is

Three unequal resistors in parallel are equivalent to a resistance 1 ohm. If two of them are in the ratio 1:2and if no resistance value is fractional the largest of the three resistances in ohms is

A tangent galvanometer properly adjusted gives a deflection of 300 when a certain current is passed through it. When the current is changed, then it gives a deflection of 450. The ratio of the current in the two cases is: