A to Z Exams

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

Temperature of cold junction in a thermo- couple is 100C and neutral temperature is 2700C, then the temperature of inversion is

A transverse wave propagating on a stretched string of linear density 3 x 10-4 kg m-1 is represented by the equation y = 0.2sin (1.5x - 60t) where x is in meters and t is in seconds. The tension in the string (in newton) 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

An observer is moving away from a sound source of frequency 100 Hz. 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 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 1.5 m is

The half life of Ra226 is 1620 years. Then the number of atoms decay in one second in 1 gm of radium (Avogadro number = 6.023x1023)

If 9.8 gms of H2SO4 is neutralized exactly with strong alkali ,the heat evolved is(?H of neutralization is 13.6 K.cal)

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

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

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 body is thrown vertically upward with an initial velocity u reaches maximum height in 6 sec.The ratio of distance travelled by the body in the first and seventh second 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

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 )

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:

An air bubble of radius 1 cm rises from the bottom portion through a liquid of density 1.5 g/cc at a constant speed of 0.25 cms-1. If the density of air is neglected, the coefficient of viscosity of the liquid is approximately, (In Pas) :

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

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

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 thin metal disc of radius 0.25 m and mass 2 kg starts from rest and rolls down an Inclined plane. If its rotational kinetic energy is 4 J at the foot of the inclined plane, then its linear velocity at the same point 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)

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 wire of length ‘l’ is bent into a circular loop of radius R and carries a current I. The magnetic field at the centre of the loop is 'B'. The same wire is now bent into a double loop of equal radii. If both loops carry the same current I and it is in the same direction, the magnetic field at the centre of the double loop will be

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 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

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:

In Young's double slit experiment, the 10th maximum of wavelength λ1 is at a distance of y1 from the central maximum. When the wavelength of the source is changed to λ2, 5th maximum is at a distance of y2 from its central maximum. then the ratio of y1 / y2 is

in a half wave rectifier output is taken across a 90 ohm load resistor. If the resistance of diode in forward biased condition is 10 ohm, the efficiency o rectification of ac power into dc power 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

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

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 bar-magnet of moment of inertia 49 x 10-2 kg-m2 vibrates in a magnetic field of induction 0.5 x10-4 T. The time period of vibration is 8.8 s. The magnetic moment of the bar magnet is

A wire of length l having tension T and radius r vibrates with fundamental frequency f.Another wire of the same metal with length 2l having tension 2T and radius 2r will vibrate with fundamental frequency

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

A sonometre wire vibrating in 4 segments is in unison with the tuning fork. Keeping the same length, if the tension made 4 times the tuning fork can still be in resonance with the wire provided the wire now vibrates in

a sonometre has 25 forks. Each produces 4 beats with the next one. If the max frequency is 288Hz,which is the frequency of last fork. The lowest frequency is

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)

When an unknown resistance and a 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 4Ω resistance is now connected in parallel to the resistance in the right gap is

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

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

A uniform wire of length 20m and weighing 5kg hangs vertically. If g=10m/s2,then the speed of transverse waves at the middle of the wire 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 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

The displacement of a particle executing SHM is given by  y = 5 sin (4t +  π/3 ) of T is the time period and the mass of the particle is 2 gms, the kinetic energy of the particle when t  = T/4 is given by

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 piece of metal weighs 45gms in air and 25gms in a liquid  of density 1.5 X 103 kg-m-3 kept at 300 C . When the temperature of the liquid is raised to 400 C the metal piece weighs 27gms . The density of the liquid at 400 C is 1.25 X 103 kg-m-3 . The coefficient of linear expansion of metal 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

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

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

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

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 proton, a deuteron (nucleus of 1H2) and an α-particle with same kinetic energy enter a region of uniform magnetic field moving at right angles to the field. The ratio of the radii of their circular  paths 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

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

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

The fundamental physical quantities that have same dimensions in the dimensional formula of torque and angular momentum are

7N14+2He4→X+1H1 then ‘X’ is

A tuning fork vibrating with a sonometer wire of length 20cm produces 5 beats per second. The beat frequency does not change if the length of the wire is changed to 21 cm. The frequency of the tuning fork must be

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 :

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 car with a horn of frequency 620 Hz, travels towards a large wall with a speed 20 m/s. If velocity of sound of 330 m/s the frequency of echo of sound of horn as heard by driver

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

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

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 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 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

The direction of the magnetic field produced by straight current carrying conductor is given by

A body projected vertically upwards crosses a point twice in its journey at a height h just after t1 and t2 seconds. Maximum height reached by the body 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)

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

A stretched string of length 2m is found to vibrate in resonance with a tuning fork of frequency 420Hz.The next higher frequency for which resonance occurs is 490Hz.The velocity of the transverse wave along this string is

The magnitude of maximum acceleration is π times that of maximum velocity of a simple harmonic oscillator. The time period of the oscillator in seconds is

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:

Which of the following Statements is not correct when a junction diode is in forward bias ?

The temperature of a thin uniform circular disc, of one metre diameter is increased by 100C. The percentage increase in moment of inertia of the disc about an axis passing through its centre and perpendicular to the circular face : (linear coefficient of expansion = 11 x l0-6/ 0C )

Which of the following statements is not true in the case of 1 Huygen's eye piece

An electrical meter of internal resistance 20Ω gives full scale deflection when one milliampere current flows through it.The maximum current that can be measured by using three resistors of resistance 12Ω each,in milliamperes 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)

A condenser of capacity 10μF is charged to a potential of 500V. Its terminals are then connected to those of an uncharged condenser of capacity 40μF. The loss of energy in connecting them together 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)

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

If a is the radius of first Bohr orbit in hydrogen atom, the radius of 3rd orbit 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 :

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)

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

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 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

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 :

The loss of weight of a solid when immersed in a liquid at 00C is .If α and β are the volume coefficients of the solid and the respectively, then the loss of weight at C is approximately

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)

Four resistors A,B,C and D form a Wheatstones bridge. The bridge is balanced when C = 100Ω .If A and B are interchanged, the bridge balances for C= 121Ω.The value of D 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

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 )

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

A proton takes 10-12 to complete one revolution in uniform magnetic field.The time taken in another orbit of double the radius in the same field is

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

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)

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