AIPMT 2007

A transformer is used to light a 100 W and 110 V lamp from a 220 V mains. If the main current is 0.5 amp, the efficiency of the transformer is approximately

The primary and secondary coils of a transformer have 50 and 1500 turns respectively. If the magnetic flux \(\phi\) linked with the primary coil is given by \(\phi\) = \(\phi\)0 + 4t, where \(\phi\) is webers, t is time in seconds and $...

What is the value of inductance L for which the current is maximum in a series LCR circuit with C = 10 \(\mu\)F and \(\omega\) = 1000 s\(-\)1 ?

If the nucleus \({}_{13}^{27}Al\) has a nuclear radius of about 3.6 fm, them \({}_{32}^{125}Te\) would have its radius approximately as

In a mass spectrometer used for measuring the masses of ions, the ions are initially accelerated by an electric potential \(V\) and then made to describe semicircular paths of radius R using a magnetic field B. If V and B are kept constant,...

The total energy of electron in the ground state of hydrogen atom is \(-\) 13.6 eV. The kinetic energy of an electron in the first excited state is

Two radioactive substances A and B have decay constants 5\(\lambda\) and \(\lambda\) respectively. At t = 0 they have the same number of nuclei. The ratio of number of nuclei of A to those of B will be (1/e)2 after a time interval

In a radioactive decay process, the negatively charged emitted \(\beta\)-particles are

A nucleus \({}_Z^AX\) has mass represented by M(A, Z). If Mp and Mn denote the mass of proton and neutron respectively and B.E. the binding energy in MeV, then

Two condensers, one of capacity C and other of capacity C/2 are connected to a V-volt battery, as shown in the figure. The work done in charging fully both the condensers is

Three resistances, P, Q, R each of 2\(\Omega\) and an unknown resistance S from the four arms of a Wheatstone bridge circuit. When a resistance of 6 \(\Omega\) is connected in parallel to S the bridge gets balanced. What is the value of S...

The total power dissipated in watt in the circuit shown here is

A 5 watt source emits monochromatic light of wavelength 5000 \(\mathop A\limits^ \circ\). When placed 0.5 m away, it liberates photoelectrons from a photosensitive metallic surface. When the source is moved to a distance of 1.0 m, the num...

A beam of electron passes undeflected through mutually perpendicular electric and magnetic fields. If the electric field is switched off, and the same magnetic field is maintained, the electrons move

Monochromatic light of frequency 6.0 \(\times\) 1014 Hz is produced by a laser. The power emitted is 2 \(\times\) 10\(-\)3 W. The number of photons emitted, on the average, by the source per second is

The electric and magnetic field of an electromagnetic wave are

Three point charges +q, \(-\) 2q and + q are placed at points (x = 0, y = a, z = 0), (x = 0, y = 0, z = 0) and (x = \(a\), y = 0, z = 0) respectively. The magnitude and direction of the electric dipole moment vector of this charge assembly ...

Charges +q and \(-\)q are placed at points A and B respectively which are a distance 2L apart, C is the midnight between A and B. The work done in moving a charge + Q along the semicircle CRD is

A hollow cylinder has a charge q coulomb within it. If \(f\) is the electric flux in units of voltmeter associated with the curved surface B, the flux linked with the plane surface A in units of V-m will be

A small coin is resting on the bottom of a beaker filled with liquid . A ray of light from the coin travels upto the surface of the liquid and moves along its surface. How fast is the light travelling in the liquid ?

Two satellites of earth, S1 and S2 are moving in the same orbit. The mass of S1 is four times the mass of S2. Which one of the following statements is true ?

An engine has an efficiency of 1/6. When the temperature of sink is reduced by 62oC, its efficiency is doubled. Temperatures of the source is

A block B is pushed momentarily along a horizontaly surface with an initial velocity V. If  \(\mu\)  is the coefficient of sliding friction between B and the surface, block B will come to rest after a time

Nickel shows ferromagnetic property at room temperature. If the temperature is increased beyond Curie temperature, then it will show

A charged particle (charge q) is moving in a circle of radius R with uniform speed v. The associated magnetic moment \(\mu\) is given by

\(\overrightarrow A\) and \(\overrightarrow B\) are two vectors and \(\theta\) is the angle between them, if $$\left| {\overrightarrow A \times \overrightarrow B } \right| = \sqrt 3 \left( {\overrightarrow A .\overrightarrow B } \right...

A particle starting from the origin (0, 0) moves in a straight line in the (x, y) planes. Its coordinates at a later time are \(\left( {\sqrt 3 ,3} \right)\). The path of the particle makes with the x-axes an angle of

The positions x of a particle with respect to time t along x-axis is given by x = 9t2 \(-\) t3 where x is in metres and t in seconds. What will be the position of this particle when it achieves maximum speed along the + x direction ?

A particle moving along x-axis has acceleration f, at time t, given by f = f0\(\left( {1 - {t \over T}} \right),\) where f0 and T are constants.The particle at t = 0 has zero velocity. In the time interval between t = 0 and the instant when...

A car moves from X to Y with a uniform speed vu and returns to Y with a uniform speed vd. The average speed for this round trip is

Under the influence of a uniform magnetic field, a charged particle moves with constant speed v in a circle of radius R. The time period of rotation of the particle

The resistance of an ammeter is 13 \(\Omega\) and its scale is graduated for a current upto 100 amps. After an additional shunt has been connected to this ammeter it becomes possible to measure currents upto 750 amperes by this meter. The ...

A mass of 2.0 kg is put on a flat pan attached to a vertical spring fixed on the ground as shown in the figure. The mass of the spring and the pan is negligible.
When pressed slightly and released the mass executes a simple harmonic motion...

The particle executing simple harmonic motion has a kinetic energy K0cos2\(\omega\)t. The maximum values of the potential energy and the total energy are respectively

A particle executes simple harmonic oscillation with an amplitude \(a\). The period of oscillation is T. The minimum time taken by the particle to travel half of the amplitude from the equilibrium position is

The phase difference between the instantaneous velocity and acceleration of a particle executing simple harmonic motion is

Assuming the sun to have a spherical outer surface of radius r, radiating like a black body at temperature toC, the power received by a unit surface, (normal to the incident rays) at a distance R from the centre of the sun is
where $$\sigm...

A black body is at 727oC. It emits energy at a rate which is proportional to

A wheel has angular acceleration of 3.0 rad/sec2 and an initial angular speed of 2.00 rad/sec. In a time of 2 sec it has rotated through an angle (in radian) of

A particle of mass m moves in the XY plane with a velocity v along the straight line AB. If the angular momentum of the particle with respect to origin O is LA when it is at A and LB when it is at B, then

A uniform rod AB of length \(l\) and mass m is free to rotate about point A. The rod is released from rest in the horizontal position. Given that the moment of inertia of the rod about A is ml2/3, the initial angular acceleration of the rod...

In the energy band diagram of a material shown below, the open circles and filled circles denote holes and electrons respectively. The material is

Which one of the following represents forward bias diode ?

In the following circuit, the output Y for all possible inputs A and B is expressed by the truth table.

For a cubic crystal structure which one of the following relations indicating the cell characteristics is correct ?

Dimensions of resistance in an electrical circuit, in terms of dimension of mass M, of length L, of time T and of current I, would be

The frequency of a light wave in a material is 2 \(\times\) 1014 Hz and wavelength is 5000 \(\mathop A\limits^ \circ\). The refractive index of material will be

A vertical spring with force constant k is fixed on a table. A ball of mass m at a height h above the free upper end of the spring falls vertically on the spring so that the spring is compressed by a distance d. The net work done in the p...