A to Z Exams

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 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 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

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

One junction of thermo couple is at 00C and the other junction is heated .Maximum current in the thermo couple is observed when hot junction is at 2400C.The temperature of the hot junction at which the direction of current reverses 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 ratio of surface areas of the two spheres is 9:16.They are put in contact and a charge of 7μC is given to the system and they are separated. Then the intensity of the electric field at a distance of 100m from the centre of smaller sphere is

An eraser weighing 2N is pressed against the black board with a force of 5N. If the co-efficient of friction is 0.4. How much force parllel to the black board is required to slide the eraser upwards

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

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:

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

Two tuning forks have frequencies 200 Hz and x. When they are sounded together 4 beats/sec heard. The value of x is

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

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

In a hall a person receives direct sound from a source 120m away. He also receives waves from the same source which reach him after being reflected from the 25m high ceiling at a point midway between them. The two waves interfere constructively for wavelengths (in metre) of

A train is travelling at 120 Kmph and blows a whistle of frequency 1000Hz.The frequency of the note heard by a stationary observer if the train is approaching him and moving away from him are (Velocity of sound in air =330 ms-1)nearly

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

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 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

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 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 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

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

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

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

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 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

Degenerate electron pressure will not be sufficient to prevent core collapse of 'white dwarf' if its mass becomes n times of solar mass. Value of n 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

Along straight conductor carrying a current of 2A is in parallel to another conductor of length 5 cm and carrying a current 3A. They are separated by a distance of 10cm B due to first conductor at second conductor 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

Consider the two following statements A and B,and identify the correct choice given in the answers:A) In photovoltaic cells the photoelectric current produced is not proportional to the Intensity of Incident light (B) In gas filled photo emissive cells, the velocity of photo-electrons depends on the wavelength of the incident radiation

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 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?

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 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:

The natural frequency of an I.-C circuit is 1,25,000 cycle/s. Then the capacitor C is replaced by another capacitor with a dielectric medium of dielectric constant K. In this case, the frequency decreases by 25 kHz. The value of K is

A straight wire of length 0.5 metre and carrying a current of 1.2 ampere is placed in a uniform magnetic field of induction 2 tesla.If the magnetic field is perpendicular to the length of the wire,the force acting on the wire

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

An intrinsic semi conductor has 1018/m3 free electron and is doped with pentavalent impurity of 1024/m3.Then the free electrons density order increases by

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

The two lenses of an achromatic doublet should have

A wave of frequency 500Hz has a velocity of 360ms-1,what is the distance between two nearest points 600 out of phase?

For the system S(s)+O2(g)→SO2(g)?

A sound wave passing through an ideal gas at NTP produces a pressure change of 0.001 dyne/cm2 during adiabatic compression. The corresponding change in temperature (γ=1.5 for the gas and atmospheric pressure is 1.013 x106 dynes/cm2) 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

A motor car approaching a cliff with velocity of 90Kmph soundsthe horn and the echo is heard after 20 seconds.Assuming the velocity of sound in air to be 332m/s,the distance between the car and cliff when the horn is sounded is

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

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

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 charges 8C and -6C are placed at a distance of separation d between them and exerts a force of magnitude  F on each other. If a charge 8C is added to each of these and they are brought nearer to by a distance d/3, the magnitude of force between them

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

The waves are represented by the following equations y1=5 sin 2π(10t-0.1x),y2=10 sin 2π(20t-0.2x)ratio of intensities l2/l1 will be

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

The waves are prepared by the following equations y1=5 sin2π(10t-0.1x) y2=10sin2 π(20t-0.2x) ratio of intensities I2/I1 will be

If the cold junction is held at 00C, the same thermo emf V of a thermocouple varies as V = 10 x 10 6t - * x 10 bt2, where t is the 40 temperature of the hot junction in 0C. The neutral temperature and the maximum value of thermo emf are respectively:

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

To a charged particle which is moving with a constant initial velocity v, uniform magnetic field is applied in the direction ot the velocity :

Two charges of +200μC and -200μC are placed at the corners B and C of an equilateral triangle ABC of side 0.1m.The force on a charge of 5μC placed at A 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)

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

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 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

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 hold 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 the gas in 'B' 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 :

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

Two identical metal spheres possess +60C and -20C of charges.They are brought in contacts and then separated by 10cm.The force between them is

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 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)

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

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

The wavelength of blue light in air is 45000A if the refractive index for blue light is 1.55 in glass what will be the wavelength of blue light in glass(c=3x108m/s)its frequency 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 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 bomb is dropped from an aircraft travelling horizontally at 150m/s at a height of 490m. The horizontal distance travelled by the bomb before it hits the ground is (in metre):

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)

The radiation emitted by a star A is 10,000 times that of the sun. If the surface temperatures of the sun and the star A are 6000 K and 2000 K respectively, the ratio of the radii of the star A and the sun is:

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 magnetic induction and the intensity of magnetic field inside an iron core of an electromagnet are 1 Wb m-2 and 150 Am-1 respectively. The relative permeability of iron is :(μ0=4π x 10-7 henry/m)

The equation connecting thermo emf with the temperature difference between the junctions 't' of a thermocouple, whose cold junction is maintained at 00C, is given by e = 2040 t - 6.2 t2. The neutral and inversion temperatures of the thermocouple in C .ire respectively and nearly equal to:

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)

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 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)

When a wire of length 10 m is subjected to a force of 100 N along its length, the lateral strain produced is 0.01 x 10-3 m. The Poisson's ratio was found to be 0.4. if the area of cross-section of wire is 0.025 m2, its Young's modulus is

The length of an elastic string is 'a' metres when the longitudinal tension is 4 N and 'b' meters when the longitudinal tension is 5 N. The length of the string in metres when the longitudinal tension is 9 N 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

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

There are 5 tube-lights each of 40W in a house.These are used on an average for 5 hours per day.In addition ,there is an immersion heater of 1500W used on an average for 1 hour per day.The number of units of electricity are consumed in a month is

A train is travelling at 120kmph and blows a whistle of frequency 1000Hz.The frequency of the note heard by a stationary observer if the train is approaching him and moving away from him are(Velocity of sound in air=330ms-1)nearly

An aluminum (resistivity ρ = 2.2 x 10-8 Ω-m) wire of a diameter 1.4 mm is used to make a4Ω resistor. The length of the wire 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

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)

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

When a liquid in a glass vessel, is heated its apparent expansion is 10.30 x 10-4same liquid when heated in a metal its apparent expansion 10.06 x 10-4/0C. The coefficient of linear expansion of the metal is : (coefficient of linear expansion of glass = 9 x 10-6/0C):

The potential energy of a proton is 3.2x10-18J at a particular point. The electric potential at this point 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:

In a potentiometer using two cells in series gave a balance length 600cm. When the same cells are connected opposing each other then balance length is 100cm. The ratio of emf’s of the cells is