A to Z Exams

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

When a positively charged particle enters a uniform magnetic field with uniform velocity, its trajectory can be : 1) a straight line 2) a circle 3) a helix

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

Consider a p-n junction as a capacitor, formed with p nnd n-materials acting as thin metal electrodes and depletion layer width acting as separation between them. Basing on this, assume that a n-p-n transistor is working as an amplifier in CE configuration. If C1 and C2 are the base-emitter and collector-emitter junction capacitances , then :

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

A free neutron decays spontaneously into :

Photoelectric current can be increased by using :

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

A sonometer consists of two wires of same material whose radii are in the ratio2:3.The tension in thick wire is 4 times the tension in thin wire.If V is velocity of transverse were in thin wire,then the velocity of transverse wave in thick wire is

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 :

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

Two lenses of focal lengths +10cm, and -15cm when put in contact behave like a convex lens .They will have zero longitudinal chromatic aberration if their dispersive powers are in the ratio

The two lenses of an achromatic doublet should have

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

In Ramsden eyepiece, the two planoconvex lenses each of focal length / are separated by a distance 12 cm. The equivalent focal length (in cm) of the eyepiece is

The pair of physical quantities not having the same dimensional formula is :

The ratio of effective focal length of Huygens eye piece and the object distance of its field lens is

The liquids at temperature 600C and 300C respectively have masses in the ratio 3 : 4 and their specific heats in the ratio 4 : 5. If the two liquids are mixed, the resultant temperature 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

A. ball of mass m moving with a velocity V*collides head on elastically with another of the same mass m but moving with a - V  (in the opposite direction). After the collision :

The equation of trajectory of a projectile is y = 10x - (5/9) x2. If we assume g =10 ms-2, the range of   projectile (in meter) 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)

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

Two parallel rails of a railway track insulated from each other and with the ground are connected to a millivoltmeter. The distance between the rails is one meter. A train is traveling with a velocity of 72 km/h along the track. The reading of the milli-voltmeter (in mV) is (Vertical component of the earth'smagnetic induction is 2 x 10-5 T)

Two short magnets AB and CD are in the X-Y plane and are parallel to X-axis and co-ordinates of their centres respectively are (0, 2) and (2, 0). Line joining the north-south poles of CD is opposite to that of AB and lies along the positive X-axis. The resultant field induction due to AB and CD at a point P (2, 2) is 100 x 10-7T. When the poles of the  magnet CD are reversed, the resultant field induction is 50 x 10-7 T. The value of magnetic moments of AB and CD (in Am2) are :

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

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)

if the length of a stretched string is shortened by 40% and the tension is increased by 44%,then the ratio of the final and initial fundamental frequencies is

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

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

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 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

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

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

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

Two small angled prisms A and B deviate the blue rays by 70 and 90 and the red rays by 50 and 70 respectively. The prism which has a greater dispersive power 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

When a thin wedge-shaped film is illuminated by a parallel beam of light of wavelength 6000A0,7 fringes are observed in a certain region of the film.The number of fringes will be observed in the same region of the film if light of wavelength 4200A0 is used

A plastic tube containing few stones is floating in a tank of water. If the stones are unloaded, the water level :

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 identical bodies have temperatures 2770C  and  670C. If the surroundings temperature is 270C, the ratio of loss of heats of the two bodies during the same interval of time is (approximately)

The plates of a parallel plate capacitor are charged upto 200 volts. A dielectric slab of thickness 4 mm is inserted between its plates. Then, to maintain the same potential difference between the plates of the capacitor, the distance between the plates is increased by 3.2 mm. The dielectric constant of the dielectric slab 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

Two wires are fixed on a sonometer wire. Their tensions are in the ratio 8 : 1, the lengths in the ratio 36 : 35, the diameters in the ratio 4 : 1 and densities in the ratio 1 : 2. If the string of higher pitch has frequency of 360 Hz the frequency of the other string is(approximately)

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

The refractive index of the material of a double convex lens is 1.5 and its focal length is 5 cm. If the radii of curvature are equal, the value of the radius of curvature (in cm) 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

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

The weight of a man in a lift moving upwards is 608 N while the weight of the same man in the lift moving downwards, with the same acceleration is 368 N. His normal weight in N 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

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

Work done by 0.1 mole of gas at 270C when it expands to double its volume at constant pressure is : (assume R = 2 cal/mol-1 K-1)

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

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:

The current decays from 5A to 2A in 0.01s in a coil. The emf induced in a coil nearby it is 30V. The mutual inductance between the coils is

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 8 N, it is in resonance with the first over- tone of the closed tube. The initial tension in the wire is

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

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

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

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:

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 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

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

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

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 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

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

In a metre bridge experiment, the ratio of the left gap resistance to right gap resistance is 2 : 3, the balance point from left is

If the angle of minimum deviation produced by equilateral prism is 300.The refractive index of the prism is

Two identical sringed instruments have frequency 100Hz. If tension in one of them is increased by 4% and they are sounded together, then number of beats in one second 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 :

The emf of a Cu-Fe thermocouple varies with the temperature T of the hot junction, the cold junction being at 100C, as Vinμv=14T-0.02T2.Determinate the neutral temperature and the of inversion.

If vibrating tuning fork of frequency 255Hz is moving with a velocity 4 ms-1 towards the wall the number of beats heard per second is (speed of found in air = 340 ms-1)

In Young's double slit experiment,first slit has width four times the width of the second slit, the ratio of the maximum intensity to the minimum intensity in the interference fringe system 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 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 tuning fork A of frequency 384Hz produces 3 beats/second when sounded with a second tuning fork B of unknown frequency.When A is filed a little,the number of beats decreased to 2beats/second.The frequency of the fork B must be

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

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

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

The R.L of water is 4/3.If ray travels 24cm in air in a given time t,the distance traveled by light in water in the same time t is

An observer to moving away from a source of sound of frequency 100 Hz at a speed of 33 m/s. If the speed of the sound in air is 330 m/s and the observed frequency is

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)

Three charges –q, +q and –q are placed at the corners of an equilateral triangle of side a. The resultant electric force on a charge +q placed at the centroid O of the triangle 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

The coils in two moving coil galvanometer have their areas in the ratio of 2:3 and number of turns in the ratio 4:5. These two coils carry the same current and are situated in the same field. The deflections produced by these coil will be in the ratio of

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) :

A 2μF condenser is charged to 500 V and then the plates are joined through a resistance in joule 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

The objective and eyepiece of an astronomical telescope are double convex lenses with refractive index 1.5. When the telescope is adjusted to infinity, the separation between the two lenses is 16 cm. If the space between the lenses is now filled with water and again telescope is adjusted for infinity, then the present separation between the lenses is

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

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

Neutral temperature of a thermo couple is 2500C.If the value of’a’ is 15μv/0C,the value of ‘b’ is

An electron beam travels with a velocity of 1.6 x 107 ms-1 perpendicularly to magnetic field of intensity 0.1 T. The radius of the path of the electron beam (me = 9 x 10-31 kg)

If the critical angle of medium is 300. Then the polarizing angle for that medium is

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

In a meter bridge a 30 Ω resistance is connected in the left gap and a pair of resistances P and Q in the right gap. Measured from the left, the balance point is 37.5 cm, when P and Q are in series and 71.4 cm when they are parallel. The values of P and Q (in Ω ) are

A string in a musical instrument is 50 cm long and its fundamental frequency  is 270 Hz.If the desired frequency of 1000Hz is to be produced, the required string length is

A magnetic needle lying parallel to a magnetic field is turned through 600.The work does on it is w. The torque required to maintain the magnetic needle in the position mentioned above is