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

The pressure of the gas in a constant volume gas thermometer is 100 cm of mercury when placed in melting ice at 1 atm. When the bulb is placed in a liquid, the pressure becomes 180 cm of mercury. The temperature of the liquid is ______.

(Given 0°C = 273 K)

The motion of a particle in the x-y plane is described by a set of following equations x = `4 sin(pi/2 - omegat)` m and y = 4 sin(ωt)m. The path of the particle will be ______.

A deuteron and an alpha particle having equal kinetic energy enter perpendicular into a magnetic field. Let `r_d` and `r_alpha` be their respective radii of the circular path. The value of `(r_d)/(r_alpha)` is equal to ______.

AC voltage V(t) = 20 sinωt of frequency 50 Hz is applied to a parallel plate capacitor. The separation between the plates is 2 mm and the area is 1 m². The amplitude of the oscillating displacement current for the applied AC voltage is ______.

[take ε₀ = 8.85 × 10^-12 F/m]

A current of 5A is passing through a non-linear magnesium wire of cross-section 0.04m². At every point, the direction of current density is at an angle of 60° with the unit vector of area of cross-section. The magnitude of electric field at every point of the conductor is ______.

Resistivity of magnesium = 44 × 10^-8 Ωm

The maximum and minimum distances of a comet from the Sun are 1.6 × 10¹² m and 8.0 × 10¹⁰ m respectively. If the speed of the comet at the nearest point is 6 × 10⁴ ms^-1, the speed at the farthest point is ______.

The time period of a simple pendulum is T inside a lift when the lift is stationary. If the lift moves upwards with an acceleration `g/2`, the time period of the pendulum will be ______.

A beam of protons with speed 4 × 10⁵ ms^-1 enters a uniform magnetic field of 0.3 T at an angle of 60° to the magnetic field. The pitch of the resulting helical path of protons is close to :

(Mass of the proton = 1.67 × 10^-27 kg, charge of the proton = 1.69 × 10^-19 C)

A circular coil of radius 10 cm is placed in a uniform magnetic field of 3.0 × 10^-5 T with its plane perpendicular to the field initially. It is rotated at constant angular speed about an axis along the diameter of coil and perpendicular to magnetic field so that it undergoes half of rotation in 0.2 s. The maximum value of EMF induced (in µV) in the coil will be close to the integer ______.

A thin strip 10 cm long is on a U-shaped wire of negligible resistance and it is connected to a spring of spring constant 0.5 Nm^-1. The assembly is kept in a uniform magnetic field of 0.1 T. If the strip is pulled from its equilibrium position and released, the number of oscillations it performs before its amplitude decreases by a factor of e is N. If the mass of the strip is 50 grams, its resistance is 10 Ω, and air drag is negligible, N will be close to ______.

A wire carrying current i has the configuration shown in figure. For the magnetic field to be zero at the centre of the circle, θ must be:

The energy levels of a certain atom for first, second and third levels are E, 4E/3 and 2E, respectively. A photon of wavelength λ is emitted for a transition 3 `→` 1. What will be the wavelength of emission for transition 2 `→` 1?

A square coil ABCD with its plane vertical is released from rest in a horizontal uniform magnetic field `vec"B"` of length 2L. The acceleration of the coil is ______.

A particle moves in one dimension from rest under the influence of a force that varies with the distance travelled by the particle as shown in the figure. The kinetic energy of the particle after it has travelled 3 m is ______.

A 20 Henry inductor coil is connected to a 10-ohm resistance in series as shown in the figure. The time at which the rate of dissipation of energy (Joule's heat) across the resistance is equal to the rate at which magnetic energy is stored in the inductor, is ______.

A conductor ABOCD moves along its bisector with a velocity 1 m/s through a perpendicular magnetic field of 1 wb/m², as shown in figure. If all the four sides are 1 m length each, then the induced emf between A and Din approx is ______V.

Ship A is sailing towards the northeast with velocity `vecv = 30hati + 50hatj` km/hr where `hati` points east and `hatj`, north. Ship B is at a distance of 80 km east and 150 km north of Ship A and is sailing west at 10 km/hr. A will be at the minimum distance from B in ______.

According to Bohr model, magnetic field at centre (at the nucleus) of a hydrogen atom due to motion of electron in the ninth orbit is proportional to:

If λ_a, λ_b and λ_c represent the K_α, K_β and L_α transition wavelengths in a hydrogen atom, respectively. Then which of the following is correct?

An α particle is moving along a circle of radius R with a constant angular velocity ω. Point A lies in the same plane at a distance 2R from the centre. Point A records magnetic field produced by α particle, if the minimum time interval between two successive times at which A records zero magnetic field is 't' the angular speed ω, in terms of t is ______.