A to Z Exams

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

A coil has an inductance of 0.05H and 100 turns and 0.02A current is passed through it.Flux linked with coil is

Two spheres of radii 12 cm and 16 cm have equal charge. The ratio tstored in the condenser is

A coil of 50 turns has dimension 10 x 10 cm. It is roated at the rate of 5 rps in a uniform magnetic field of flux density 0.7T. The maximum emf included in it is

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

An open pipe resonates with a tuning fork of frequency 500Hz.It is observed that two successive notes are formed at distances 16cm and 46 cm from the open end .the speed of sound in air in the pipe is

An ideal transformer has 400turns in the primary and 200 turns in the secondary.If the primary is connected to a 12 V battery,then the secondary voltage is

For the system S(s)+O2(g)→SO2(g)?

A person aiming to reach the exactly opposite point on the bank of a stream is swimming with a speed of 0.5ms-1 at an angle of 1200 with the direction of flow of water.The speed of water in the stream, in ms-1, is:

The focal length of the lenses of an astronomical telescope are 50 cm and 5cm. The length of the telescope when the image is formed at the least distance of distinct vision 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

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 solid spheres A and B made of the same material have radii rA and rB respectively. Both the spheres are cooled from the same temperature under the conditions valid for Newton's law of cooling. The ratio of the rate of change of temperature of A and B is :

Frequency of tuning fork A is 250 Hz. It produces 4 beats/sec with another tuning fork B. When A is filed, the beat frequency is 6 beats/sec. The frequency of B 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

One mole of a gas occupies 100 ml at 50 mm pressure.The volume of 2 mole of the gas at 100 mm pressure and same temperature is

A charge of 4 μC is placed in a uniform electric field of intensity 100N/C. The force acting on the charge is

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

The phase difference between two vibrating particles separated by a distance of 11 metres into medium through which a progressive wave is travelling is 13200.If the frequency of the disturbance is 105 Hz, the phase velocity of the progressive wave in ms-l

A stretched wire of some length under a tension is vibrating with its fundamental frequency. Its length is decreased by 45% and tension is increased by 21%.Now its fundamental frequency

Two wires of same material and same length have their resistances in the ratio 5:7.The ratio of the masses of the wires is

A train approaching a level crossing at a speed of 20m/s sounds a horn of frequency 628Hz when 80m form the crossing.A person is standing at 60m from the level crossing on a road which is perpendicular to the railway track.Then the apparent frequency heard by the person is (velocity of sound in air is 330m/s)

The frequency of the sound of a car horn as recorded by an observer towards whom the car is moving differs from the frequency of the horn by 10%.Assuming the velocity of sound in air to be 330ms-1,the velocity of the car is

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

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

The extension of a wire by application of a load is 0.3 cm.The extension in a wire of same material, but of double the length and half the radius of cross-section, by the same load will be, in cm :

A source of sound is approaching a stationary observer with a velocity 1/10th of the velocity of sound in air so that apparent decrease in the wavelength of sound waves is 10cm.If the observer is approaching the same source of sound at rest with a velocity 1/5th of velocity of sound in air,the apparent increase in the frequency of sound is(velocity of sound in air=340m/s)

A light ray is incident on a transparent medium of μ=1.732 at the polarizing angle.The angle of refraction is

Two bar magnets A, B are placed one over the other and are allowed to vibrate in a vibration magnetometer. They make 20 oscillations per minute when the similar poles of A and B are on the same side, while they make 15 oscillations per minute when their opposite poles lie on the same side. If MA and MB are the magnetic moments of A and B and if MA > MB, the ratio of MA and MB 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)

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

In an electric motor,wires carrying a current of 5A are placed at right angles to magnetic field of induction 0.8T.If each wire has length of 20cm,then the force acting on each wire

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 )

A coil has 1,000 turns and 500cm2 as its area.The plane of the coil is placed at right angles to a magnetic induction field of 2x10-5web/m2.The coil is rotated through 1800 in 0.2 seconds.The average emf induced in the coil,in milli volts,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:

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 :

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

In Huygen's eyepiece

If the earth suddenly stops rotating, the value of g at equator would :

A capacitor of 8 μF is charged to a potential of 1000V. The energy stored in the capacitor is

The minimum force required to move a body up an inclined plane is three times the minimum force required to prevent it from sliding down the plane. If the coefficientof friction between the body and the inclined plane is 1/2√3 the angle of the inclined plane is :

A double convex lens of focal length 30cm is made of glass of R.I.1.6. When it is immersed in a liquid, the focal length is found to be 90cm. The R.I of the liquid is

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

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

A charge of 10 units is divided so that force between the two charges is maximum when placed 2cm apart. The two charges 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)

The photoelectric work function of a metal surface is 2eV.When light of frequency 1.5x1015Hz is incident on it,the maximum kinetic energy of the photo electrons approximately is

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

Emission of electrons in photoelectric effect is possible if :

In two separate collisions, the coefficient of restitutions e1 and e2 are in the ratio 3:1. In the first collision the relative velocity of approach is twice the relative velocity of separation, then the ratio between relative velocity of approach and the relative velocity of separation in the second collision is

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

A first order reaction has commenced with 0.2M solution of the reactants. If the molarity of the solution falls to 0.02M after 100 minutes the rate constant of the reaction 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

Two wires A and B,made of same material and having their lengths in the ratio 6:1 are connected in series.The potential differences across the wires are 3V and 2V respectively.If rA and rB the radii of A and B respectively,then rA/rB is

An electron beam moving with a speed of 2x107ms-1 enters a magnetic field of induction 3x10-3T, directed perpendicular to its direction of motion. The intensity of electric field applied so that the electron beam is undeflected due to the magnetic field is

Charge 20,30,-40 and 50 μC are at the corners of a square of 10cm. The field at the point of intersection of the diagonals 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

A cell in secondary circuit gives null deflection for 2.5 m length of potentiometer having 10 m length of wire If the length of the potentiometer wire is increased by 1 m without changing the cell in the primary, the position of the null point now is

An open pipe resonates to a frequency f1 and a closed pipe resonates to a frequency f2.if they are joined together to form a longer tube, then it will resonate to a frequency of (neglect end corrections and consider fundamental frequencies)

When the angle of inclination of an inclined plane is θ, an object slides down with uniform velocity. If the same object is pushed with a initial velocity u on the same inclined plane; it goes up the plane and stops at a certain distance on the plane. Thereafter the body :

The angle of a prism is 600 and the angle of minimum deviation of light passing through it is observed to be 400. The angle of incidence of light is

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 current of 0.5A produes a deflection of 600 in tangent galvanometer. The current that produces a deflection of 300 in the same galvanometer is

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

When a uniform wire of radius r, is stretched by a 2 kg weight the increase in its length is 2.00 mm. If the radius of the wire is r/2 and other conditions remaining the same, the increase in its length 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)

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)

A wire of length 44cm is bent into a circle and a current of 9.8A is passed through it.The intensity of magnetic induction at the centre of the circle is

The coefficient of kinetic friction between a body and the surface of an inclined plane at 450 is 0.5. If g = 9.8 ms-2,the acceleration of the body down the inclined plane, in ms-2is:

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 :

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

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 flint glass prism is of refracting angle 50.Its refractive index for C line is 1.790 and for F line is 1.805.The angular dispersion of C and F lines is

Two condensers of capacities 4 μF and 5 μF are joined in series. The potential difference across 5 μF is 10 V then the potential difference across 4 μF condenser is:

A 100 PFcapacitor is charged to a potential difference of 24V.It is connected to an uncharged capacitor 20PF.what will be the new potential difference across 100PF capacitor

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 fundamental frequency of a sonometer wire is 200 Hz when a body whose relative density 4 is suspended at the end of wire.The fundamental frequency of the same wire when the suspended body is made to immerse in water is

A metal string is fixed between rigid supports. It is initially at negligible tension. Its youngs modulus is ‘Y’ density is ρ and coefficient of linear expansion is α. It is now cooled through a temperature ‘t’ transverse waves will move along it with a speed.

A 25 watt,220 volt bulb and a 100 watt,220 volt bulb are connected in series across 440 volt line

A body is projected vertically upwards at time t = 0 and it is seen at a height 'H' at time t1 and t2 seconds during its flight. The maximum height attained is : (g is acceleration due to gravity)

Two identical piano wires have a fundamental frequency of 600 c/s when kept under the same tension. What fractional increase in the tension of one wire will lead to the occurrence of 6 beats per second when both wires vibrate simultaneously      

A body 'A' starts from rest with an acceleration 'a1'. After 2 seconds another body 'B' starts from rest with an acceleration a2.If they travel equal distance in the 5th second after the start of 'A'.a1:a2 equal to:

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 256 Hz,the frequency of B 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 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)

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)

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 thin magnetic iron rod of lenght 30cm is suspended in a uniform magnetic filed.Its time period of oscillation is $s.It is broken into three equal parts.The time period in seconds of oscialltion of one part when suspended in the same magnetic filed is:

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

Two charges of 10μC and -90μC are separated by a distance of 24cm.Electrostatic field strength from the smaller charge is zero at a distance of

The pole strength of a 12 cm long bar magnet is 2.0 A-m. The magnetic induction at a point 10 cm away from the centre of the magnet on the axial line is (μ0/4∏=10-7Hm-1)

A body of weight "64N" is pushed with just enough force to start it moving across a horizontal floor and the same force continues to act afterwards, if the coefficients of static and dynamic friction are 0.6 and 0.4 respectively, the acceleration of the body is: (acceleration due to gravity = g)

In a thermo couple the cold junction is at 300C.The temperature of inversion is found to be 5400C,Then the neutral temperature is

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 :

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 difference between heats of reaction at constant pressure and at constant volume for the reaction 2C6H6(l)+15O2(g) → 12CO2(g)+6H2O(l) at 250C in KJ is

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

A highly conducting sheet of aluminium foil negligible thickness is placed between the plates of a parallel plate capacitor.If thecapacitance before the insertion of foil was 10μF,its value after the insertion of foil will be

A fork gives 5beats/sec with a 40cm long sonometer wire.If the length of the wire is shortened by 1 cm,the number of beats/sec is still the same.The frequency of the fork is