NEET Questions

Taking the Bohr radius as a₀ = 53 pm, the radius of Li⁺⁺ ion in its ground state, on the basis of Bohr’s model, will be about

Which statements are correct? (A) Inside a conductor electrostatic potential is zero. (B) At the surface of charge conductor electrostatic field must be normal to the surface at every point (C) The interior of a conductor can have no excess charge in the static situation (D) The electrostatic potential is constant throughout the volume of the conductor and has the same value(as inside) on it surface (E) Electric field at the surface of charge conductor is σ/ε₀. (F) Whatever be the charge and field configuration outside any cavity in a conductor remains shielded from outside electric influence

If vectors \( \vec{A} \) and \( \vec{B} \) are such that \(|\vec{A} + \vec{B}| = |\vec{A} - \vec{B}|\), then \(|\vec{A} - \vec{B}|\) may be equated to

Consider three charges q₁, q₂ and q₃ each equal to q, at the vertices of an equilateral triangle of side l. What is the force on a charge Q placed at the centroid of the triangle?

If a wave gets refracted into a denser medium, then which of the following is true?

The position of an object moving along x-axis is given by x = a + bt², where a = 8.5 m and b = 2.5 m s⁻² and t is measured in seconds. The average velocity of the object between t = 2 s and t = 4 s is

The cylindrical tube of a spray pump has a cross-section of 8 cm², one end of which has 40 fine holes each of area 10⁻⁸ m². If the liquid flows inside the tube with a speed of 0.15 m min⁻¹, the speed with which the liquid is ejected through the holes is:

Two insulated concentric coils, each of radius R, placed at right angles to each other, carry currents I and √3I respectively. The magnitude of the net magnetic field at their common centre will be

Figure below show regular hexagons, with charges at the vertices. In which case, the electric field at the centre zero?

The work done in rotating a bar magnet of magnetic moment M from its unstable equilibrium position to its stable equilibrium position in a uniform magnetic field B is

A steel rail of length 5 m and area of cross section 40 cm² is prevented from expanding along its length while the temperature rises by 10°C. If coefficient of linear expansion and Young's modulus of steel are 1.2 × 10⁻⁵ K⁻¹ and 2 × 10¹¹ Nm⁻² respectively, the force developed in the rail is approximately:

1 Tesla equal to

Which of the following material has its magnetic susceptibility χ in the range 0 < χ < ε, where ε is positive and small?

A stone tied to the end of a string 100 cm long is whirled in a horizontal circle with a constant speed. If the stone makes 14 revolutions in 22 s, then the acceleration of the stone is

Statement^{-1} : If an electron and proton are freely falling under gravity from a certain distance then time to reach the ground is same. Statement^{-2} : If an electron and proton are made to fall a certain distance in a uniform electric field time taken by electron is MORE than proton (neglect gravitational effect).

Time taken by sunlight to pass through a window of thickness 4 mm whose refractive index is 3/2 is

The acceleration for electron and proton due to electrical force of their mutual attraction when they are 1 Å apart is

A particle is moving on a circular path of radius R with constant speed v. During motion off the particle from point A to point B

Match the Column I (electric lines of force) with Column II (types of charge) and select the correct answer from the codes given below.

If the unit of force is 100 N, unit of length is 10 m and unit of time is 100 s, what is the unit of mass in this system of units?

A particle is moving with speed \(V = b\sqrt{x}\) along positive x-axis. Calculate the speed of the particle at time \(t = \tau\) (assume that the particle is at origin at \(t = 0\)).

In a linear simple harmonic motion (SHM) (A) Restoring force is directly proportional to the displacement. (B) The acceleration and displacement are opposite in direction. (C) The velocity is maximum at mean position. (D) The acceleration is minimum at extreme points. Choose the correct answer from the options given below:

The reading of the ammeter for a silicon diode in the given circuit is:

A truck and a car moving with the same kinetic energy are brought to rest by the application of brakes which provide equal retarding forces. Which of them will come to rest in a shorter distance?

The potential of a large liquid drop when eight liquid drops are combined is 20 V, then the potential of each single drop was

There is an air filled 1pF parallel plate capacitor. When the plate separation is doubled and the space is filled with wax, the capacitance increases to 2pF. The dielectric constant of wax is

A body of mass 2 kg travels according to the law x(t) = pt + qt² + rt³ where, q = 4 m/s², p = 3 m s⁻¹ and r = 5 m s⁻³. The force acting on the body at t = 2 s is

A galvanometer of resistance 100 Ω gives full scale deflection for a current of 1.0 mA. It is converted into an ammeter of range 0-1 Å. The resistance of the ammeter will be close to

If a gas is compressed adiabatically by doing work of 150 J the change in internal energy of the gas is

In a series resonant circuit, having L, C and R as its elements, the resonant current is I. The power dissipated in the circuit at resonance is

The energy of a photon of light of wavelength 450 nₘ is

The maximum horizontal range of a projectile is 400 m. The maximum value of height attained by it will be

The stress-strain graph for a metal wire is as shown in the figure. In the graph, the region in which elasticity is maintained the ultimate strength and fracture points are represented by

The energy of an electron in the ground state of hydrogen atom is^{-13}.6 eV. The kinetic and potential energy of the electron in the first excited state will be

Temperature dependence of resistivity ρ(T) of semiconductors, insulators and metals is significantly based on the following factors : (1) number of charge carriers can change with temperature T (2) time interval between two successive collisions can depend on T.

In figure given below, assuming the diodes to be ideal

In a series LR circuit XL = R and power factor of the circuit is P₁. When capacitor with capacitance C such that Xₗ = Xc is put in series, the power factor becomes P₂. The ratio P₁/P₂ is:

Time period of a charged particle undergoing a circular motion in a uniform magnetic field is independent of

The magnetic energy stored in an inductor of inductance 4μH carrying a current of 2A is

If the frequency of human heart is 1.25 Hz, the number of heart beats in 1 minute is

When light propagates through a material When light propagate permittivity εᵣ and relative medium of relative the velocity of light, v is given permeability μᵣ, the light in vacuum) by: (c = velocity of light in vacuum)

A particle executing simple harmonic motion with time period T. The time period with which its kinetic energy oscillates is

The dimensions of magnetic flux are

The pressure of a gas changes linearly with volume from A to B as shown in figure. If no heat is supplied to or extracted from the gas then change in the internal energy of the gas will be

In the nth orbit, the energy of an electron Eₙ = -13.6/n² eV for hydrogen atom. The energy required to take the electron from first orbit to second orbit will be

The variation of the stopping potential (V₀) with the frequency (ν) of the incident radiation for four metals A, B, C and D is shown in the figure. For the same frequency of incident radiation producing photo-electrons in all metals, the kinetic energy of photo-electrons will be maximum for metal

If for a gas \( \frac{R}{C_v} = 0.67 \), this gas is made up of molecules which are

A particle (A) is dropped from a height and another particle (B) is thrown in horizontal direction with speed of 5 m/sec from the same height. The correct statement is

How much mass has to be converted into energy to produce electric power of 500 MW for one hour?

A wheatstone bridge is used to determine the value of unknown resistance X by adjusting the variable resistance Y as shown in the figure. For the most precise measurement of X, the resistances P and Q :