A to Z Exams

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

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

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

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

The magnitude of the force between parallel conductors, each of length 110 cm,carrying a current of 10A and separated by a distance of 10 cm is

Three condensers 1μF,2μF and 3μF are connected in series to a p.d of 330volt.The PD across the plates of 3μF is

The magnetic induction at the centre due to motion of electron in first Bohr orbit is B. magnetic filed due to the motion of electron in second Bohr orbit at the centre will bw

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

The least distance of distinct vision is 25cm. If the focal length of convex lens is 10 cm. It acts as a simple microscope of maximum magnification

A small square loop of wire of side l is placed inside a large square loop of side L(L>>1). If the loops are coplanar and their centres coincide, the mutual induction of the system is directlv proportional to :

A cylindrical resonance tube open at both ends has a fundamental “f” in air.If half of the length is dipped vertically in water,the fundamental frequency of the air column will be

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

Magnetic field induction at the centre of a circular coil of radius 5 cm and carrying a current 0.9 A is (in S.I. units) (ε0 = absolute permittivity of air in S.I. units; velocity of light = 3 x 108 ms-1)

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

A sonometer wire produces 2 beats per second with a tuning fork, when the length of the wire is either 102cm or 1004cm.The frequency of the tuning fork 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

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:

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:

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

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

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 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

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

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 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?

To measure the field B between the poles of an electromagnet,a small test loop of area 1cm2,resistance 10Ω and 20 turns is pulled out of it.A galvanometer shows that the total charge of 2μC passed through the loop.The value of resistance connected in series is

The equation of wave is y=10cos2π((t/0.02)-(x/10)),where ‘t’ is in seconds an x in cm.The phase difference between two points separated by a distance of 5cm at any instant 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)

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?

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

The temperature of the system decreases in the process of

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

A constant voltage of 25 V is applied to a series L-R circuit at t = 0, by closing a switch. What is the potential difference across the resistor and the inductor at time t = 0

A light of length 75 cm is suspended from the ceiling horizontally by means of two vertical wires of equal length tied to its ends. One of the wires is made of steel of cross section 0.2 sq cm.The Position along the rod at which a weight may be hung to produce equal stresses.ysteel=20x1010 N/m2,Ybrass=10x1010N/m2

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:

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

In Youngs double slit experiment the separation between the slits is halved and the distance between the slits and screen is doubled .The fringe width is

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

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

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

The crictical angle for light going from a medium in which wavelength is 4000A0 to medium in which wavelength is 6000A0

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 :

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

In Millikans oil drop experiment, an oil drop of radius r charge q falls under the gravity with a terminal velocity Vg and moves up with a terminal velocity Ve in the uniform vertical electric field of intensity E. If η is coefficient of viscosity of air, the charge of oil drop is

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 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

In an n-type semiconductor, the Fermi energy level lies

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

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

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

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

The rate constant of the reaction at temperature 200K is 10 times than the rate constant at 400K.The activation energy of the reaction 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

An infinitely long thin straight wire has uniform linear charge density of 1/3 coul.m-1.Then the magnitude of the electric intensity at a point 18 cm away is

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

A motor cycle starts from rest and accelerates along a straight path at 2m/s2.At the starting point of the motor cycle, there is a stationary electric siren. How far has the motor cycle gone when the driver hears the frequency of the siren at 94% of its value when the motor cycle was at rest?(speed of sound=330ms-1)

A motor car approaching a cliff with a velocity of 90 kmph sounds the 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 2 MeV proton is moving perpendicular to a uniform magnetic field of 2.5 tesla. The force on the proton is (mass of proton = 1.6 x 10-27 kg)

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

The centre of mass of three particles of masses 1 kg, 2 kg and 3 kg is at (2, 2, 2).The position of the fourth mass of 4 kg to be placed in the system as that the new centre of mass is at (0, 0, 0) 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

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

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

The dispersive powers of the materials of two lenses forming an achromatic combination are in the ratio of 4:3. Effective focal length of the two lenses is +60 cm then the focal lengths of the lenses should be

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 :

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)

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

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

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

Two wires A and B are of lengths 40 cm and 30 cm, A is bent into a circle of radius r and B into an arc of radius r. A current i1 passed.through A and i2 through B. To have the same magnetic inductions at the centre, the ratio of    i1  :   i2  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 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:

Two strings A and B of lengths. LA = 80 cm and LB = x cm respectively are used separately in a sonometer. The ratio of their densities {dA/dB) is 0.81. The diameter of B is one-half that of A. If the strings have the same tension and fundamental frequency the value of x 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 velocity of propagation of sound is 330 m/s, in air. If the third harmonic of the fundamental that can be exerted in an open ended tube is 450 Hz, the length of the tube 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

An inductance 1 H is connected in series with an AC source of 220 V and 50 Hz. The inductive reactance (in ohm) is :

A uniform rod of length 8a and mass 6m lies on a smooth horizontal surface. Two point masses m and 2m moving in the same plane with speed 2 v and v repectively strike the rod perpendicularly at distances a and 2a from the mid point of the rod in the opposite directions and stick to the rod. The angular velocity of the system immediately after the collision 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

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

When a dielectric slab of the same area of cross-section and thickness equal to 2/3 of the separation is introduced between the plates of a parallel plate capacitor, its capacitance becomes 2.25 times the original value. The dielectric constant of the material of the slab 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

The work function of a certain metal is 3.31 x 10-19 J. Then the maximum kinetic energy of photo electrons emitted by incident radiation of wavelength 5000 A0 is

A potentiometer having wire of 4m length is connected to the terminals of a battery with a steady voltage.A leclanche cell has a null points at 1m,If the length of the potentiometer wire is increased by 1m,the position of the null points 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

In Sun, the important source of energy is

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.

A magnifying glass is made of a combination of convergent lens of power +20 diopters and a divergent lens of power -4 diopters .If the image is formed atleast distance of distinct vision (25cm), the magnifying power 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 :

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

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

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

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

Two strings of the same material and the same area of cross-section ae used in sonometre experiment.One is loaded with 12kg and the other with 3kg,the fundamental frequency of the first string is equal to the overtone of the second string.If the length of the second string is 100cm,then the length of the first string is

7N14+2He4→X+1H1 then ‘X’ is

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