A to Z Exams

A force of 5 N making an angle 8 with the horizontal acting on an object displaces it by 0.4 m along the horizontal direction. If the object gains kinetic energy of 1 J the horizontal component of the force is :

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

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 :

A step down transformer has a supply line voltage of 2200V in to 220V. The primary coil has 5000 turns. The efficiency and power transmitted by the transformer are 90% and 8 kilowatt respectively. Then the number of turns in the secondary is

Two wires of the same material but of different diameters carry the same current I. If the ratio of their diameters is 2 : 1, then the corresponding ratio of their mean drift velocities will be

Four bulbs each marked 40 W. 250 V are connected in series with 250 V source. The total power output 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)

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

Two point charges -q and +q are located at points (0, 0, -a) and (0, 0, a) respectively. The electric potential at a point (0, 0, z), where z > a

A condenser 1μF is charged to a potential of 1000 volt. The energy stored in the condenser is:

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 displacement of a particle moving in a straight line is given by x = 2t2+t+5 where x is expressed in meter and 't' in second.The acceleration at t = 2sec is

A primary coil and secondary coil are placed close to each other. A current, which changes at the rate of 25 amp in a millisecond, is present in the primary coil. If the mutual inductance is 92x10-6 Henries,then the value of induced emf in the secondary coil is

A compound slab is made with two different materials A and B with coefficient of thermal  conductivity  KA = 2KB  and thickness XA=(1 / 2) XB. If the face of the A surface is at 1000C and that of the B surface is at 250C the temperature of the common surface will be

A particle of mass 4 m explodes into three pieces of masses m, m and 2 m. The equal masses move along X- and Y-axes with velocities 4 ms-1 and 6 ms-1 respectively. The magnitude of the velocity of the heavier mass 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

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 long parallel conductors carrying different currents are separated by a distance 20 cm in air such that force per unit length on each conductor is 5 x 10-3 N/m If the current in first conductor is 50 A then the current in the second conductor is:

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

A whistling engine is approaching a stationary observer with a velocity of 110m/s. The velocity of sound is 330m/s. The ratio of frequencies as heard by the observer as the engine approaches and recedes is

The temperature of the system decreases in the process of

Apparent frequency of sound is 505 Hz when the listener is approaching a stationary source of sound with a velocity 1% of the velocity of sound in air. The actual frequency of sound is

A parallel plate capacitor has a capacitance of 10 micro farads without dielectric. A dielectric of dielectric constant 2 is used to fill exactly half the thickness between the plates. The capacitance in micro farads,now is

A free neutron decays spontaneously into :

The de Broglie wavelength of an electron moving with a velocity of 1.5x108m/s is equal to that of a photon. The ratio of kinetic energy of the electron to that of the photon (C=3x108m/s)

Two point charges are separated by 3 cm of air and 3 cm of a dielectric of relative permittivity 4.The equivalent air separation between them is (as far as their coulombic interaction is concerned)

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:

When an unknown resistance of 4Ω are connected in the left and right gaps of a meterbridge,the balance point is obtained at 50cm.The shift in the balance point if a 4 Ω resistance is now connected in parallel to the right gap 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

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 source producing sound of frequency 170 Hz is approaching a stationary observer with a velocity of 17 ms-1. The apparent change in the wavelength of sound heard by the observer is: (speed of sound in air=340ms-1)

Two positive charges 12μC and 10μC are initially separated by 10cm.The work done in bringing the two charges 4cm closer is

An object of mass 2 m is projected with a speed of 100 ms-1    at an angle θ = sin-1 (3/5) to the horizontal. At the highest point, the object breaks into two pieces of same mass m and the first one comes to rest. The distance between the point of projection and the point of landing of the bigger piece (in meter) is (Given g =10 m/s2)    

Assertion (A): Propagation of light through an optical fibre is due to total internal reflection taking place at the core-clad interface.Reason (R): Refractive index of the material of the core of the optical fibre is greater than that of air.

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

A transverse wave propagating on a stretched string of linear density 3x10-4kgm-1 is represented by the equation y=0.2sin(1.5x+60t) where x is in meter and t is in seconds. The tension in the string in N.

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 tyre of a motor car contains air at 150C. If the temperature increases to 350C, the approximate percentage increase in pressure is (ignore to expansion of tyre)

A 2 kg mass moving on a smooth frictioriless surface with a velocity of 10 m/s, hits another 2 kg mass kept at rest in an elastic collision. After collision, if they move together:

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      

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 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 resistance of a conductor is 1.08Ω.To reduce it to 1Ω,the resistance that must be connected is

The two lenses of an achromatic doublet should have

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 :

A circular coil of radius 11cm,carries and current of 2.5 amperes.If it has 700 turns,the flux density at the centre of the coil 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

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:

If a body is in equilibrium under a set of non-collinear forces, the minimum number of forces has to be

X-rays of energy 50 KeV are scattered from a carbon target. The scattered rays are detected at 900 from the incident beam. the percentage change in wave length approximately [mo=9.0x10-31kg, c=3x108 m/sec] is

A juggler maintains four balls on motion, making each inturn rise to a height 20m from his hand. Where will the other three balls be at the instant when the fourth one is just leaving the hand?

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)

The speed of transverse vibrations in a stretched string is 700cm/s.If the string is 2m long,the frequency with which it resonates in fundamental mode is

A man slides down on a telegraphic pole with  an acceleration equal to one-fourth of acceleration due to gravity. The frictional force between man and pole is equal to in terms of man's weight w

A potentiometer having a 4m long wire is connected to the terminals of a battery of constant output voltage. A Leclanche cell has a balancing length of 1m. If the length of the potentiometer wire is increased by 1m, then the position of the null point is

The dark lines in the solar spectrum are due to:

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

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 :

A particle is projected from the ground with an initial velocity of 20ms-1 at an angle of 300 with horizontal. The magnitude of change in velocity in 0.5 seconds is(g=10ms-1)

A motor car of mass 300 kg is moving with a velocity of 25 m/s, by applying brakes the car was brought to rest in a distance of 15 metres. The force of retardation in newton 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)

The energy released by fission from 2g of 23592U in KWH is.(The energy released per fission is 200MeV).

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

Percentage of mass lost during the fission of 42U235 approximately is

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

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

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)

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

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 :

The focal length of an equi-convex lens is greater than the radius of curvature of any of the surfaces. Then the refractive index of the material of the lens 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

An n-p-n transistor power amplifier in C-E configuration gives :

Electrons ejected from the surface of a metal, when light of certain frequency is incident on it, are stopped fully by a retarding potential of 3 volts. Photoelectric effect in this metallic surface begins at a frequency 6 x 1014s-1. The frequency of the incident light in s-1is : [ Planck's constant = 6.4 x 10-34Js, charge on the electron = 1.6 x 10-19C]

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?

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:

A rod with linear charge density λ is bent in the shape of circular ring.The electric potential at the centre of the circular ring is

A quantity of heat Q is supplied to a mono atomic ideal gas which expands at constant pressure. The fraction of heat that goes into work done by the gas is :

An infinite number of charges each of magnitude q are placed on x-axis at distances of 1, 2, 4, 8, ….. meter from the origin. The intensity of the electric field at origin is

With a standard rectangular bar magnet of length (l), breadth (b; b < < l) and magnetic moment M, the time period of the magnet in a vibration magnetometer is 4 s. If the magnet is cut normal to its length into four equal pieces, the time period (in seconds) with one of the pieces is :

In a meterbridge experiment,the balance length is 40cm.the resistance in the gap opposite to this length of wire is 8 ohm.The resistance in the other gap 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 )

Two identical stringed instruments have a frequency of 100Hz.The tension in one of them is increased by 4%.If they are now sounded together the number of beats per second is

A pipe of length l1 closed at one end is kept in a chamber of gas of density ρ1.A second pipe open at both ends is placed in a second chamber of gas of density ρ2.The compressibility of both.The gases is equal.If frequency of first overtone in both the cases is equal,the length of the second pipe is

If two identical bar magnets, each of length l, pole strength m and magnetic moment  M are placed perpendicular to each other with their unlike poles in contact, the magnetic moment of the combination is :

A steel wire can withstand a load up to 2940 N, A load of 150 kg, is suspended from a rigid support. The maximum angle through which the wire can be displaced from the mean position, so that the wire does not break when the load passes through the position of equilibrium, is

When two capacitors are joined in series the resultant capacity is 2.4 μF and when the same two are joined in parallel the resultant capacity is 10μF.their individual capacities are

The radioactivity of a sample is 'X' at a time 't1' and ‘Y’ at a time 't2'. If the mean life time of the specimen is г the number of atoms that have disintegrated in the time interval (t1 – t2) 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

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

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)

A 1.0 HP IP motor pumps out water from a well of 30m and fills water tank of volume 2238 litres at a height of 10 m from the ground. The running time of the motor to fill the empty water tank is: (g= 10 ms-2)

Thomson coefficient of a conductor is 10μVK. The two ends of it are kept at 500 C and 600 C respectively. Amount of heat absorbed by the conductor when a charge of 10 C flows through it, is:

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

Two bodies of 6 kg and 4 kg masses have their velocity   5i^-2j^+10k^   and   10i^-2j^+5k^ respectively. Then the velocity of their centre of mass 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 :

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

A certain number of beats are heard when two tuning forks of natural frequencies n1 and n2 are sounded together. The number of beats heard when one of the forks is loaded :

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 :

Two charges each of 100 micro coulomb are separated in a medium of relative permittivity 2 by a distance of 5cm.The force between them is