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

An insect moves with a constant velocity v from one corner of a room to other corner which is opposite of the first corner along the largest diagonal of room. If the insect can not fly and dimensions of room is a × a × a, then the minimum time in which the insect can move is `"a"/"v"`. times the square root of a number n, then n is equal to ______.

When a galvanometer is shunted with a 4 Ω resistance, the deflection is reduced to one-fifth. If the galvanometer is further shunted with a 2 Ω wire. The further reduction (find the ratio of decrease in current to the previous current) in the deflection will be (the main current remains the same)

A galvanometer coil bas 500 turns and each tum has an average area of 3 × 10^-4 m². If a torque of 1.5 Nm is required to keep this coil parallel to a magnetic field when a current of 0.5 A is flowing through it, the strength of the field (in T) is ______.

A galvanometer having a resistance of 20 Ω and 30 Ω division on both sides has figure of merit 0.005 ampere/division. The resistance that should be connected in series such that it can be used as a voltmeter upto 15 volt, is ______.

A moving coil galvanometer has 150 equal divisions. Its current sensitivity is 10-divisions per milliampere and voltage sensitivity is 2 divisions per millivolt. In order that each division reads 1 volt, the resistance in ohms needed to be connected in series with the coil will be ______.

A bag of sand of mass 9.8 kg is suspended by a rope. A bullet of 200 g travelling with speed 10 ms^-1 gets embedded in it, then loss of kinetic energy will be ______.

An alpha-particle of mass m suffers 1-dimensional elastic collision with a nucleus at rest of unknown mass. It is scattered directly backwards losing, 64% of its initial kinetic energy. The mass of the nucleus is ______.

Two point masses of mass m₁ = fM and m₂ = (1 - f) M (f < 1) are in outer space (far from gravitational influence of other objects) at a distance R from each other. They move in circular orbits about their centre of mass with angular velocities ω₁ for m₁ and ω₂ for m₂. In that case ______.

An ideal gas in a cylinder is separated by a piston in such a way that the entropy of one part is S₁ and that of the other part is S₂. Given that S₁ > S₂. If the piston is removed then the total entropy of the system will be ______.

The root means the square speed of smoke particles of mass 5 × 10^-17 kg in their Brownian motion in air at NTP is approximate.

[Given k = 1.38 × 10^-23 JK^-1]

What will be the effect on the root mean square velocity of oxygen molecules if the temperature is doubled and the oxygen molecule dissociates into atomic oxygen?

For a given gas at 1 atm pressure, rms speed of the molecules is 200 m/s at 127°C. At 2 atm pressure and at 227°C; the rms speed of the molecules will be ______.

A silver atom in a solid oscillates in simple harmonic motion in some direction with a frequency of 10¹²/sec. What is the force constant of the bonds connecting one atom with the other?

(Mole wt. of silver = 108 and Avagadro number = 6.02 × 10²³ gm mole^-1)

In an experiment to determine the velocity of sound in air at room temperature using a resonance tube, the first resonance is observed when the air column has a length of 20.0 cm for a tuning fork of frequency 400 Hz is used. The velocity of the sound at room temperature is 336 ms^-1. The third resonance is observed when the air column has a length of ______ cm.

Match List I with List II

Choose the correct answer from the options given below:

One main scale division of a vernier callipers is 'a' cm and n^th division of the vernier scale coincide with (n - 1)^th division of the main scale. The least count of the callipers in mm is ______.

The pressure acting on a submarine is 3 × 10⁵ Pa at a certain depth. If the depth is doubled, the percentage increase in the pressure acting on the submarine would be ______.

(Assume that atmospheric pressure is 1 × 10⁵ Pa density of water is 10³ kg m^–3, g = 10 ms^–2)

The least count of the main scale of a vernier callipers is 1 mm . Its vernier scale is divided into 10 divisions and coincide with 9 divisions of the main scale. When jaws are touching each other, the 7^th division of vernier scale coincides with a division of main scale and the zero of vernier scale is lying right side of the zero of main scale. When this vernier is used to measure length of cylinder the zero of the vernier scale between 3.1 cm and 3.2 cm and 4^th VSD coincides with a main scale division. The length of the cylinder is: (VSD is vernier scale division)

An electric fan has blades of length 30 cm as measured from the axis of rotation. If the fan is rotating at 1200 r.p.m. The acceleration of a point on the tip of the blade is about:

The main scale of a spectrometer is divided into 720 division in all. If circular vernier scale consists of 30 divisions, the least count of the instrument is ______.

(Given: 30 vernier divisions coincide with 29 main scale divisions)