AIPMT Prelims Physics Class 12 Questions

A coil of resistance 400 Ω is placed in a magnetic field. If the magnetic flux ϕ (wb) linked with the coil varies with time t (sec) as ϕ = 50 t² + 4, the current in the coil at t = 2 sec is

An electric dipole of moment ‘p’ is placed in an electric field of intensity ‘E’. The dipole acquires a position such that the axis of the dipole makes an angle θ with the direction of the field. Assuming that the potential energy of the dipole to be zero when θ = 90°, the torque and the potential energy of the dipole will respectively be

If the nuclear radius of ²⁷Al is 3.6 Fermi, the approximate nuclear radius of ⁶⁴Cu in Fermi is:

Two similar coils of radius R are lying concentrically with their planes at right angles to each other. The currents flowing in them are I and 2I, respectively. The resultant magnetic field induction at the centre will be

When a biconvex lens of glass having refractive index 1.47 is dipped in a liquid, it acts as a plane sheet of glass. This implies that the liquid must have refractive index

Two ideal diodes are connected to a battery as shown in the circuit. The current supplied by the battery is

A ring is made of a wire having a resistance R₀ = 12 Ω. Find the points A and B, as shown in the figure, at which a current carrying conductor should be connected so that the resistance R of the sub circuit between these points is equal to 8/3 Ω.

The magnifying power of a telescope is 9. When it is adjusted for parallel rays the distance between the objective and eyepiece is 20 cm. The focal length of lenses are

What is the flux through a cube of side ‘a’ if a point charge of q is at one of its corner?

An α-particle moves in a circular path of radius 0.83 cm in the presence of a magnetic field of 0.25 Wb/m². The de Broglie wavelength associated with the particle will be

The figure shows a logic circuit with two inputs A and B and the output C. The voltage wave forms across A, B and C are as given. The logic circuit gate is

A compass needle which is allowed to move in a horizontal plane is taken to a geomagnetic pole. It:

A 200 W sodium street lamp emits yellow light of wavelength 0.6 μm. Assuming it to be 25% efficient in converting electrical energy to light, the number of photons of yellow light it emits per second is

An electron of a stationary hydrogen atom passes from the fifth energy level to the ground level. The velocity that the atom acquired as a result of photon emission will be

In the circuit shown the cells A and B have negligible resistances. For Vₐ = 12V, R₁ = 500 Ω and R = 100 Ω the galvanometer (G) shows no deflection. The value of V_b is

Monochromatic radiation emitted when electron on hydrogen atom jumps from first excited to the ground state irradiates a photosensitive material. The stopping potential is measured to be 3.57 V. The threshold frequency of the material is

If voltage across a bulb rated 220 Vol$t^{-100}$ Watt drops by 2.5% of its rated value, the percentage of the rated value by which the power would decrease is

Transfer characteristics [output voltage(V₀) vs input voltage (Vᵢ)] for a base biased transistor in CE configuration is as shown in the figure. For using transistor as a switch, it is used

A concave mirror of focal length f₁ is placed at a distance of d from a convex lens of focal length f₂. A beam of light coming from infinity and falling on this convex lens-concave mirror combination returns to infinity. The distance ‘d’ must equal

A milli voltmeter of 25 milli volt range is to be converted into an ammeter of 25 ampere range. The value (in Ω) of necessary shunt will be

A ray of light is incident at an angle of incidence, i on one face of a prism of angle A (assumed to be small) and emerges normally from the opposite face. If the refractive index of the prism is μ, the angle of incidence i, is nearly equal to

Electron in hydrogen atom first jumps from third excited state to second excited state and then from second excited to the first excited state. The ratio of the wavelengths λ₁ : λ₂ emitted in the two cases is

The electric field associated with an e.m. wave in vacuum is given by E̅ = î40cos(kz − 6 × 10⁸t), where E, z and t are in volt/m, meter and seconds respectively. The value of wave vector k is

An alternating electric field, of frequency ν, is applied across the dees (radius = R) of a cyclotron that is being used to accelerate protons (mass = m). The operating magnetic field (B) used in the cyclotron and the kinetic energy (K) of the proton beam, produced by it, are given by

The current (I) in the inductance is varying with time according to the plot shown in figure. Which one of the following is the correct variation of voltage with time in the coil?

In an electrical circuit R, L, C and an a.c voltage source are all connected in series. When L is removed from the circuit, the phase difference between the voltage and the current in the circuit is π/3. If instead, C is removed from the circuit, the phase difference is again π/3. The power factor of the circuit is

A radioactive nucleus of mass M emits a photon of frequency ν and the nucleus recoils. The recoil energy will be

A charge Q is enclosed by a Gaussian spherical surface of radius R. If the radius is doubled, then the outward electric flux will

Four electric charges +q, +q, -q and -q are placed at the corners of a square of side 2L (see figure). The electric potential at point A, midway between the two charges +q and +q, is

A parallel plate condenser has an electric field E (V/m) in the space between the plates. If the distance between the plates is d (m) and area of each plate is A (m²) the energy (joules) stored in the condenser is

If power dissipated in the 9 Ω resistor in the circuit shown is 36 Watt, the potential difference across the 2 Ω resistor is

A current of 2 Å flows through a 2 Ω resistor when connected across a battery. The same battery supplies a current of 0.5 Å when connected across a 9 Ω resistor. The internal resistance of the battery is

A right angle isosceles triangle ABC is placed in a uniform magnetic field acting along AB. If the magnetic force on the arm BC is $\vec{F}$, the force on the arm AC is

The power obtained in a reactor using U²³⁵ disintegration is 1000 kW. The mass decay of U²³⁵ per hour is

There are four light-weight-rod samples, A, B, C, D separately suspended by threads. A bar magnet is slowly brought near each sample and the following observations are noted:

(i) A is feebly repelled

(ii) B is feebly attracted

(iii) C is strongly attracted

(iv) D remains unaffected.

Which one of the following is true?

The electric and the magnetic field, associated with an e.m. wave, propagating along the +z-axis, can be represented by

An electric field and a magnetic field are acting along the same direction in certain region. If an electron is projected in the region such that its velocity is pointed along direction of fields, then the electron

The current i in a coil varies with time as shown in the figure. The variation of induced emf with time would be

In an AC circuit an alternating voltage e = 200√2 sin 100t volts is connected to capacitor of capacity 1 μF. The r.m.s. value of the current in the circuit is

An AC voltage is applied to a resistor R and inductor L in series. If R and the inductive reactance are both equal to 3 Ω, the phase difference between the applied voltage and the current in the circuit is

The decreasing order of wavelength of infrared, microwave, ultraviolet and gamma rays is

Which of the following is due to total internal reflection?

A biconvex lens has a radius of curvature of magnitude 20 cm. Which one of the following options describe best the image formed of an object of height 2 cm placed 30 cm from the lens?

In photoelectric emission process from a metal of work function 1.8 eV, the kinetic energy of most energetic electrons is 0.5 eV. The corresponding stopping potential is

Electrons used in an electron microscope are accelerated by a voltage of 25 kV. If the voltage is increased to 100 kV then the de-Broglie wavelength associated with the electrons would

Light of two different frequencies whose photons have energies 1 eV and 2.5 eV respectively illuminate a metallic surface whose work function is 0.5 eV successively. Ratio of maximum speeds of emitted electrons will be

In a Thomson's experiment, the velocity of electrons emitted from the electron gun can be increased by

Photoelectric emission occurs only when the incident light has more than a certain minimum

Fusion reaction takes place at high temperature because

A nucleus m/nX emits one α particle and two β-particles. The resulting nucleus is