JEE Main entrance exam Question Bank Solutions for Physics (JEE Main)

The angle of deviation through a prism is minimum when

1. Incident rays and emergent rays are symmetric to the prism.
2. The refracted ray inside the prism becomes parallel to its base.
3. The angle of incidence is equal to that of the angle of emergence.
4. When the angle of emergence has doubled the angle of incidence.

Choose the correct answer from the options given below:

Magnetic materials used for making permanent magnets (P) and magnets in a transformer (T) have different properties of the following, which property best matches for the type of magnet required ?

One cubic plate, having a 15 cm side, floats on water surface. If surface tension of water is 60 dyne/cm. To lift this plate from water, Find the extra force required against weight.

The dispersive powers of flint glass and crown glass are 0.053 and 0.034, respectively and their mean refractive indices are 1.68 and 1.53 for white light. Calculate the angle of the flint glass prism required to form an achromatic combination with a crown glass prism of refracting angle 4°:

dispersive power of crown glass? Given that µ_v = 1.5230, µ_r = 1.5145

A prism of refractive index `sqrt2` and refracting angle A produces minimum deviation δ_m of a ray on one face at an angle of incidence 45°, The values of A and δ_m are, respectively ______.

Which of the following statements are correct?

1. Electric monopoles do not exist whereas magnetic monopoles exist.
2. Magnetic field lines due to a solenoid at its ends and outside cannot be completely straight and confined.
3. Magnetic field lines are completely confined within a toroid.
4. Magnetic field lines inside a bar magnet are not parallel.
5. χ = -1 is the condition for a perfect diamagnetic material, where x is its magnetic susceptibility.

The susceptibility of a paramagnetic material is 99. The permeability of the material in Wb/A-m is ______.

[permeability of the free space μ₀ = 4π × 10^-7 Wb/A - m]

The value of aluminium susceptibility is 2.2 × 10^-5. The percentage increase in the magnetic field if space within a current carrying toroid is filled with aluminium is  `"x"/10^4`. Then the value of x is ______.

A telegraph line of length 100 km has a capacity of 0.01 µF/ km and it carries an alternating current at 0.5 kilo cycle per second. If minimum impedance is required, then the value of the inductance that needs to be introduced in series is ______ mH. (if π = `sqrt10`)

In an LCR series circuit, an inductor 30 mH and a resistor 1 Ω are connected to an AC source of angular frequency 300 rad/s. The value of capacitance for which, the current leads the voltage by 45° is `1/x xx 10^-3` F. Then the value of x is ______.

A sinusoidal voltage of peak value 250 V is applied to a series LCR circuit, in which R = 8 Ω, L = 24 mH, and C = 60 μF. The value of power dissipated at resonant conditions is 'x' kW.

The value of x to the nearest integer is ______.

A cylindrical vessel containing a liquid is rotated about its axis so that the liquid rises at its sides as shown in the figure. The radius of vessel is 5 cm and the angular speed of rotation is ω rad s^-1. The difference in the height, h (in cm) of liquid at the centre of vessel and at the side will be :

In a YDSE experiment two slits S₁ and S₂ have separation of d = 2 mm. The distance of the screen is D = 8/5 m. Source S starts moving from a very large distance towards S₂ perpendicular to S₁S₂ as shown in figure. The wavelength of monochromatic light is 500 nm. The number of maximas observed on the screen at point P as the source moves towards S₂ is 3995 + n. The value of n is ______.

In a Young's double slit experiment, the fringe width is found to be 0.4 mm. If the whole apparatus is immersed in water of refractive index `(4/3)`, without disturbing the geometrical arrangement, the new fringe width will be :

Two bar magnets oscillate in a horizontal plane in earth's magnetic field with time periods of 3 s and 4 s respectively. If their moments of inertia are in the ratio of 3 : 2 then the ratio of their magnetic moments will be ______.

A hoop and a solid cylinder of same mass and radius are made of a permanent magnetic material with their magnetic moment parallel to their respective axes. But the magnetic moment of hoop is twice of solid cylinder. They are placed in a uniform magnetic field in such a manner that their magnetic moments make a small angle with the field. If the oscillation periods of hoop and cylinder are T_h and T_c respectively, then:

The frequencies at which the current amplitude in an LCR series circuit becomes `1/sqrt2` times its maximum value are 212 rad s^-1 and 232 rad^-1. The value of resistance in the circuit is R = 5Ω. The self inductance in the circuit is ______ mH.

An LCR circuit contains resistance of 110 Ω and a supply of 220 V at 300 rad/s angular frequency. If only capacitance is removed from the circuit, current lags behind the voltage by 45°. If on the other hand, only inductor is removed the current leads by 45° with the applied voltage. The rms current flowing in the circuit will be ______.

In a young double-slit apparatus the screen is rotated by 60° about an axis parallel to the slits. The slit separation is 3 mm, the slit-to-screen distance (at the central fringe) is 4 m, and the wavelength of light is 450 nm. The separation between the third dark fringe on either side of the central fringe is ______.