A to Z Exams

Two positive charges q1=4x10-6C and q2=9x10-6C are placed 10cm apart in air. The position of a third charge to be placed between them, such that there will be no resultant force on it is

Center of mass of two particles with masses 2kg and 1kg located at (1,0,1) and (2,2,0) has the co-ordinates of

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 cell of emf e1 in the secondary circuit gives null deflection for1.5m length of potentiometer of wire length 10m.If another cell of emf e2 is connected in series with e1 then null reflection was obtained for 2.5 m length.Then e1:e2

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

A oil drop having a mass 4.8 x10-10 g and charge 2.4 x 10-18 C stands still between two charged horizontal plates separated by a distance of 1 cm. If now the polarity of the plates is changed, instantaneous acceleration of the drop is : (g = 10 ms-2)

Two particles P and Q are located at distance rp and rq respectively from the centre of a rotating disc such that rp > rq

To generate power of 3.2 MW, the number of fissions of U235 per minute is : (Energy released per fission =200 MeV; 1eV=1.6x10-19J)

A ray of light undergoes deviation of 300 when incident on an equilateral prism of refractive index√2.What is the angle of the ray inside the prism with the base of the prism?

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

The lengths of two wires made of same material are 2m and 1m. Their radii are 1mm and 2mm. The ratio of their specific resistances is

A 4Ω resistor in series with 8Ωresistance are connected to 12 V supply.If another resistor of 8Ω is connected across the 8Ω resistor the current drawn from source would be

In a chemical reaction, ΔH=150KJ and ΔS=100JK-1 at 300K. ΔG would be

In a Ramsden eyepiece of effective focal length 3 cm the focal length of eye lens, in cm, 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

Δλ is the difference between the wave length of kα line and the minimum wavelength of the continuous X-ray spectrum when the X-ray tube is operated at a voltage V. If the operating voltage is changed to v/3 , then the above difference is Δλ'. Then :

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

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

An electric current passes through a long straight wire. At a distance 5cm from the wire, the magnetic field is B. The field at 20cm from the wire would be:

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

In a photoelectric cell, wavelength of the incident light is changed from 4000A0 to 3600A0. Change in stopping potential will be nearly

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

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:

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

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

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.

The number of turns in primary and secondary coils of a transformer is 50 and 200. If the current in the primary coil is 4 A, then the current in the secondary coil is

A radioactive sample has half life of 5 days. To decay from 8 micro-curies to 1 micro-curie, the number of days taken will be :

A long string with a charge of λ per unit length passes through an imaginary cube of edge a. The maximum flux of the electric field through the cube will be

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

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

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

A black body radiates energy at the rate of E watt/m2 at a high temperature T K. When the temperature is reduced to (T/2) K, the radiant energy is

A man 50 kg is standing at one end on a boat of length 25 m and mass 200 kg. If he starts running and when he reaches the other end, he has a velocity 2 ms-1 with respect to the boat.The final velocity of the boat is : (in ms-1)

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

A segment of wire vibrates with a fundamental frequency of 450 Hz under a tension of 9 kg wt. Then tension at which the fundamental frequency of the same wire becomes 900 Hz is

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 )

The machine gun fires 240 bullets per minute. If the mass of each bullet is 10 g and the velocity of the bullets is 600 ms-1, the power (in kW) of the gun is :

The elementary particles heavier than nucleons are called

Two cells A and B are connected in the secondary circuit of a potentiometer one at a time and the balancing length are respectively 400 cm and 440 cm. The emf of the cell A is 1.08 volt. The emf of the second cell B in volts is :

A light ray of wavelength λ is passing through a pin hole of diameter D and the effect is observed on a screen placed at a distance L from the pin hole. The approximations of geometrical optics are applicable if

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 :

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 steady current is set up in a metallic wire of non-uniform cross-section. Then the drift velocity related the area of cross-section (A) as

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

While connecting 6 cells in a battery in series,ina tape recorder,by mistake one cell is connected with reverse polarity.If the effective resistance of load is 24 ohm and internal resistance of each cell is one ohm and emf 1.5V,the current delivered by the battery is

If π is Peltier coefficient,heat evolved at a junction when a current of 10 mA passes for 10 seconds in joules is

The difference between volume and pressure coefficients of an ideal gas is :

In an experiment on photoelectric emission from a metallic surface, wavelength of incident light is 2xl0-7 m and stopping potential is 2.5 V. The threshold frequency of the metal (in Hz)   approximately   (charge  of electron e= 1.6 x 10-19 C  Planck's constant h = 6.67 x 10-34 J-s)

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

(A): bending of a conducting wire effects electrical resistance (R): Resistance of a wire depends on resistivity of that material

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

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

A vehicle sounding a whistle of frequency 256 Hz is moving on a straight road, towards a hill with a velocity of 10 ms-1 . The number of beats per second observed by a person travelling in the vehicle is : (Velocity of sound =330 ms-1)

Two ions having masses in the ratio 1:1 and charges 1 : 2 are projected into uniform magnetic field perpendicular to the field with speeds in the ratio 2:3. The ratio of the radii of circular paths along with the two particles move is

A wooden block is dropped from the top of a cliff 100m high.Simultaneously a bullet of mass 10g is fired from the foor of the cliff upwards with a velocity of 100 m/s.The bullet and wooden block will meet each other after a time:

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,

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 short bar magnet in a vibrating magnetometer makes 16 oscillations in 4 seconds.Another short magnet with same length and width having moment of inertia 1.5 times the first one is placed over the first magnet and oscillated. Neglecting the induced magnetization, the time period of the combination 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

In Atwood’s machine, two masses 3 kg and 5 kg are connected by a light string which passes over a frictionless pulley. The support of the pulley is attached to the ceiling of a compartment of a train. If the train moves in a horizontal direction with a constant acceleration 8 ms-2 the tension in the string in Newtons is(g=10ms-2)

A 2 kg body and 3 kg body have equal momentum. If the kinetic energy of 3 kg body is 10 Joules, the kinetic energy of 2 kg body will be, (in joules) :

A horizontal beam of vertically polarized light of intensity 43W/m2 is sent through two polarizing sheets. The polarizing direction of the first is 600 to the vertical , and that of the second is horizontal. The intensity of the light transmitted by the pair of sheets is (nearly)

A photo-cathode is irradiated in turn by light of wavelengths 4000 A0 and 6200 A0 respectively. The ratio of the stopping potentials in the two cases is found to be 2:1. The work function of the photo-cathode is nearly

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

Two charges 2C and 6C are separated by a finite distance. If a charge of -4C is added to each of them, the initial force of 12 x 103 N will change to

If the angle of minimum deviation produced by an equilateral prosm is 300, the refractive index of material of prism 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

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

Three point charges 1C, -2C and -2C are placed at the vertices of an equilateral triangle triangle of side 1 metre The work done by an external force to increase the separation of the charges to 2 metre in joule is : (ε0= permittivity of air)

A body is projected from the earth at angle 300 with the horizontal with some intial velocity. If its range is 20 m, the maximum height reached by it is : (in metres)

A soap bubble of radius r is blown up to form a bubble of radius 2r under isothermal conditions. If T is the surface tension of soap solution, the energy spent in the blowing

In Potentiometer experiment,the balancing length with a cell in the secondary circuit is found to be 480cm.when a resistor of 8 ohm is connected in parallel to the cell the balancing length is found to be 420cm.The internal resistance of the cell is

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

A fire engine with its bell ringing with a frequency of 200 Hz is moving with a velocity of 54 kmph towards an observer at rest near a hut on fire. The apparent frequency of sound heard by the observer is (velocity of sound in air = 300ms-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:

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

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

A sonometer is set on the floor of a lift. When the lift is at rest, the sonometre wire vibrates with fundamental frequency 256Hz.When the lift goes up with acceleration a=9g/16,the frequency of vibration of the same wire changes to

A sonometer wire produces 2 beats per second with a tuning fork, when the length of the wire is either 102cm or 1004cm.The frequency of the tuning fork 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:

A person is in between two vertical mountains.The person fires a gun then hears the first echo from the nearby mountain in a time 3s and hears second echo from far mountain in a time 4s.The person hears the third echo after

The mass of a balloon with its contents is 15kg. It is descending with an acceleration equal to half that of acceleration due to gravity. If it is to go up with the same acceleration, keeping the volume same, its mass should be decreased by

Dispersive power of the material of a prism is 0.0221.If the deviation produced by it for yellow colour is 380,then the angular dispersion between red and violet colour is

Two tuning forks A and B produce 6 beats per second when sounded together. When B is slightly loaded with wax the beats are reduced to 4 per second. If the frequency of A is 512 Hz the frequency of B is

Two very wide parallel glass plates are held vertically at a small separation r,and dipped in water surface tension S.Some water climbs up in the gap between the plates. If P0 is the atmospheric pressure of water just below the water surface in the region between the two plates is

A whistle of frequency 540Hz rotates in a horizontal circle of radius 2m at an angular speed of 15rad/s. The highest frequency heard by a listener away from the circle at rest with respect to the centre of circle (velocity of sound in air=330m/s)

Identify the increasing order of the angular velocities of the following :1.earth rotating about its own axis2.hour's hand of a clock3.second's hand of a clock4.flywheel of radius 2 m making 300 rpm

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 of K. When x and y are vibrated together 4 beats per second. The frequencies of x and y are

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)

Consider the following statements A and B and identify the correct answers given below :A : Peltier coefficient is numerically equal to the potential difference across the junctions of the thermocouple through which current is flowing.B : According to Thomson, energy is neither absorbed nor evolved at the junction of a thermocouple but is observed or evolved only along the lengths of both the conductors.

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

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

A body of mass 5 kg makes an elastic collision with another body at rest and continues to move in the original direction after collision with a velocity equal to 1/10th  of its original velocity. Then the mass of the second body is

The velocity of a listener who is moving away from a stationary source of sound such that the listener notices 5% apparent decrease in frequency of sound is(Velocity of sound in air=340ms-1)

A pipe having an internal diameter ‘D’ is connected to anther pipe of same size. water flows into the second pope through ‘n’ holes, each of diameter ‘d’. If the water in the first pipe has speed ‘V’, the speed of water leaving the second pipe is

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

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 rectangular class room of volume 20×15×10 m3 has a surface whose average absorption coefficient is 0.035. When a material of area 1500m2 is brought into the room, the reverberation time falls to 2.5 seconds. The absorption coefficient of the material is nearly

The effect due to uniform magnetic field on a freely suspended magnetic needle is as follows :