NEET Mock Test - 25 - NEET MCQ

The photo electric threshold wave length for potassium (work function being 2eV) is

A stone of mass 1 kg tied to a light inextensible string of length L = 10/3 m is whirling in a circular path of radius L in a vertical plane. If the ratio of the maximum tension in the string to the minimum tension in the string is 4 and if g is taken to be 10 m/sec², the speed of the stone at the highest point of the circle is

In a circuit, n identical bulbs, each of power 'P' are joined in series across a power supply. The total power drawn by the bulbs is

The equivalent resistance between the terminals P and Q of infinite network as shown in the figure is

Mixed He⁺ and o²⁺ ions (mass of He⁺ = 4 amu and that of o²⁺ = 16 amu) beam passes a region of constant perpendicualr magnetic field. If kinetic energy of all the ions is same then

Which of the following phenomena is observed when black discharge occurs in a discharge tube ?

Light of two different frequencies whose photons have energies leV and 2.5eV respectively, successively illuminates a metal of work function 0.5eV. The ratio of maximum kinetic energy of the emitted electron will be

Photoelectric effect proves the

The current passing through a coil of 5 H is decreasing at the rate of 2 A/s. The emf developed in the coil is

An electromagnetic wave passing through vacuum is described by the equations: E = E₀ sin (kx-ωt) and B = B₀ sin (Kx-ωt). Then

The idea of displacement current was introduced by

A neutral sphere of radius r and density ρ is intended to be suspended with an electric field E existing on earth's surface directed vertically up. What fraction of the electrons should be removed from the sphere? Given that, the atomic number and atomic mass of material of the sphere are Z and A respectively. Avogadro's number is N_A. Assume that the sphere is able to hold the necessary charge without any leakage.

The two point charges of 2C are -6C attract each other with a force of 12N. A -ve charge of 2C is added to each of the above charges. Now the force between them is

If the rotational speed of earth is increased, then weight of a body at the equator

Which of the following is the example of ideal black body

When the pressure on 1200 ml of a gas is increased from 70 cm to 120 cm of mercury at constant temperature, then new volume of the gas will be

A body of mass 10 kg lies on a rough horizontal surface. When a horizontal force of F newtons acts on it, it gets an acceleration of 5 m−s⁻². And when the horizontal force is doubled, it gets an acceleration of 18 m−s⁻². The coefficient of friction between the body and the horizontal surface is (Take g = 10 m−s⁻²)

The magnetic force acting on a charged particle of charge − 2μC in a magnetic field of 2T acting in y direction, when the particle velocity is 

A bar magnet of pole strength 2 A-m is kept in a magnetic field of induction 4 x 10⁻⁵ wbm⁻² such that the axis of the magnet makes an angle 30° with the direction of the field. The couple acting on the magnet is found to be 80 x 10⁻⁷ N - m . Then the distance between the poles of the magnet is

At a certain place, the horizontal component of the earth's magnetic field is B₀, and the angle of dip is 60°. The intensity of earth's magnetic field at that place will be

The rate of flow of water in a capillary tube of length 'l' and radius 'r' is 'V'. The rate of flow in another capillary tube of length '2l' and radius '2r' for same pressure difference would be

The breaking stress of a wire depends upon

Which of the following is more effective in inducing nuclear fission

A radioactive sample at any instant has its disintegration rate 5000 disintegrations per minute. After 5 min, the rate is 1250 disintegrations per min. Then, the decay constant (per minute) is

Nuclear fusion occur in

A coin is placed on a horizontal platform, which undergoes vertical simple harmonic motion of angular frequency ω. The amplitude of oscillations is gradually increased. The coin will have contact with the platform for the first time. (i) at the higher position of the platform (ii) at the mean position of the patform (iii) for an amplitude of g/ω² (iv) for an amplitude of √2/ω

An equiconvex lens of glass of focal length 0.1 m is cut along a plane ⊥ er to principal axis into two equal parts. The ratio of focal length of new lenses formed is