NEET 2019 Physics Questions

Taking gravitational potential energy at infinity to be zero, the change in PE (final − initial) of a mass m raised to height h above the earth's surface (radius R) is:

The work done to raise a mass m from the surface of the earth to a height h equal to the radius of the earth R is:

A satellite has period 24 h at height 6R_E from the earth's surface. The period of another satellite at height 2.5 R_E from the surface is:

The work done to raise a mass m from the surface of the earth to a height equal to the radius of the earth R is:

A mass falls from height h and its fall-time t is measured in units of the period T of a simple pendulum. On earth t = 2T. The setup is taken to another planet of half the earth's mass and the same radius, giving times t' and T'. Then:

A body weighs 200 N on the surface of the earth. How much will it weigh half way down to the centre of the earth?

Two particles A and B are moving in uniform circular motion in concentric circles of radii $r_A$ and $r_B$ with speeds $v_A$ and $v_B$ respectively. Their time period of rotation is the same. The ratio of the angular speed of A to that of B is:

The speed of a swimmer in still water is 20 m/s. The speed of river water is 10 m/s flowing due east. If he is standing on the south bank and wishes to cross the river along the shortest path, the angle at which he should make his strokes with respect to north is:

Two bullets are fired horizontally and simultaneously towards each other from the rooftops of two buildings 100 m apart and of the same height 200 m, with the same speed 25 m/s. When and where will the two bullets collide? ($g=10\ \mathrm{m/s^2}$)

The radius of a circle, the period of revolution, the initial position and the sense of revolution are indicated in the figure (radius 3 m, period $T=4$ s, particle P starts at $t=0$ on the $+y$ axis). The $y$-projection of the radius vector of the rotating particle P is:

A particle starting from rest moves in a circle of radius $r$. It attains a velocity of $V_0$ m/s in the $n$th round. Its angular acceleration is:

A particle of mass 5m at rest suddenly breaks on its own into three fragments. Two fragments of mass m each move along mutually perpendicular directions with speed v each. The energy released during the process is

When an object is shot up a long smooth inclined plane kept at 60^° with the horizontal, it travels a distance x₁ along the plane. When the inclination is decreased to 30^° and the same object is shot with the same velocity, it travels a distance x₂. Then x₁:x₂ will be

An object of mass 500 g, initially at rest, is acted upon by a variable force whose X-component varies with X as shown in the graph. The velocities of the object at the points X = 8 m and X = 12 m would be, respectively (nearly)

A force F=20+10y acts on a particle in the y-direction, where F is in newton and y in metre. The work done by this force to move the particle from y=0 to y=1 m is

Body A of mass 4m moving with speed u collides with another body B of mass 2m at rest. The collision is head-on and elastic in nature. After the collision the fraction of energy lost by the colliding body A is

A particle P revolves in a circle as shown in the figure. The radius of the circle, the period of revolution, the initial position and the sense of revolution are indicated. The y-projection of the radius vector of the rotating particle P is

The displacement of a particle executing simple harmonic motion is y = A₀ + A sin ωt + B cos ωt. The amplitude of its oscillation is

The average velocity of a particle executing SHM over one complete vibration is

The distance covered by a particle undergoing SHM in one time period is (amplitude = A)

A mass falls from a height h and its time of fall t is recorded in terms of the time period T of a simple pendulum. On the surface of the earth it is found that t = 2T. The entire set-up is taken to another planet whose mass is half that of the earth and whose radius is the same. The experiment is repeated and the corresponding times are t′ and T′. Then

A mass m is attached to a thin wire and whirled in a vertical circle. The wire is most likely to break when:

A particle moving with velocity V is acted upon by three forces represented by the sides of a triangle PQR (taken in order). The velocity of the particle will:

A particle of mass 5m at rest suddenly breaks on its own into three fragments. Two fragments, of mass m each, move along mutually perpendicular directions with speed v each. The energy released during the process is:

A block of mass 10 kg is in contact with the inner wall of a hollow cylindrical drum of radius 1 m. The coefficient of friction between the block and the wall is 0.1. The minimum angular velocity of the drum (rotating about its vertical axis) needed to keep the block stationary is (g = 10 m/s²):

A copper rod of length 88 cm and an aluminium rod of unknown length have their increase in length independent of the increase in temperature. The length of the aluminium rod is: (α_Cu = 1.7 × 10⁻⁵ K⁻¹, α_Al = 2.2 × 10⁻⁵ K⁻¹)

The SI unit of thermal conductivity is:

An object kept in a large room (air temperature 25 °C) takes 12 minutes to cool from 80 °C to 70 °C. The time taken by the same object to cool from 70 °C to 60 °C would be nearly:

A deep pond is covered by a frozen ice layer of thickness x while the outside air is at a steady −26 °C (water below is at 0 °C). The ice has thermal conductivity K, density ρ and specific latent heat of fusion L. The rate of increase of the thickness of the ice layer at this instant is:

A small hole of cross-sectional area 2 mm² is present near the bottom of a fully filled open tank of height 2 m. Taking g = 10 m s⁻², the rate of flow of water through the open hole would be nearly:

A soap bubble of radius 1 mm is blown from a detergent solution of surface tension 2.5 × 10⁻² N m⁻¹. The pressure inside the bubble equals the pressure at a point Z₀ below the free surface of water in a container. Taking g = 10 m s⁻² and density of water = 10³ kg m⁻³, the value of Z₀ is:

Two small spherical metal balls of equal mass are made from materials of densities ρ₁ and ρ₂ (ρ₁ = 8ρ₂) and have radii 1 mm and 2 mm respectively. They fall vertically from rest in a viscous medium of coefficient of viscosity η and density 0.1ρ₂. The ratio of their terminal velocities is:

In a U-tube, water and oil are in the left and right arms respectively. The heights of the water and oil columns (measured from the bottom) are 15 cm and 20 cm respectively. The density of the oil is: (take ρ_water = 1000 kg m⁻³)

The main scale of a vernier calliper has n divisions/cm. n divisions of the vernier scale coincide with (n-1) divisions of the main scale. The least count of the vernier calliper is:

In an experiment, the percentage errors in the measurement of physical quantities A, B, C and D are 1%, 2%, 3% and 4% respectively. Then the maximum percentage error in the measurement X, where X = A^(1/2) B² / (C^(1/3) D³), will be:

The unit of thermal conductivity is:

A person in a lift drops a coin. The coin takes time $t_1$ to reach the floor when the lift is at rest, and time $t_2$ when the lift is moving up with uniform velocity. Then:

A person travelling in a straight line moves with a constant velocity $v_1$ for a certain distance x and with a constant velocity $v_2$ for the next equal distance. The average velocity v is given by the relation:

A solid cylinder of mass 2 kg and radius 4 cm rotates about its axis at 3 rpm. The torque required to stop it within 2 revolutions is:

A particle starts from rest and moves in a circle of radius r, attaining speed V0 in the n-th round. Its angular acceleration is:

An ideal gas expands isothermally from 10⁻³ m³ to 10⁻² m³ at 300 K against a constant external pressure of 10⁵ N m⁻². The work done on the gas is:

Increase in temperature of a gas filled in a container would lead to:

When a block of mass M is suspended by a long wire of length L, the length of the wire becomes (L + l). The elastic potential energy stored in the extended wire is:

The stress-strain curves are drawn for two different materials X and Y. It is observed that the ultimate strength point and the fracture point are close to each other for material X, but are far apart for material Y. We can say that materials X and Y are likely to be (respectively)

In which of the following processes, heat is neither absorbed nor released by a system?

An ideal gas expands isothermally from $10^{-3}$ m$^3$ to $10^{-2}$ m$^3$ at $300$ K against a constant external pressure of $10^{5}$ N/m$^2$. The work done ON the gas is

A tuning fork of frequency 800 Hz produces resonance in a resonance-column tube (upper end open, lower end closed by the water surface). Successive resonances occur at lengths 9.75 cm, 31.25 cm and 52.75 cm. The speed of sound in air is:

A hollow metal sphere of radius R is uniformly charged. The electric field due to the sphere at a distance r from the centre

Two metal spheres, one of radius R and the other of radius 2R, have the same surface charge density σ. They are brought in contact and then separated. What will be the new surface charge densities on them?

Two parallel infinite line charges with linear charge densities +λ C/m and −λ C/m are placed at a distance of 2R in free space. What is the electric field mid-way between the two line charges?

A sphere encloses an electric dipole with charges ±3 × 10⁻⁶ C. What is the total electric flux across the sphere?

Two point charges A and B, having charges +Q and −Q respectively, are placed at a certain distance apart and the force acting between them is F. If 25% of the charge of A is transferred to B, then the force between the charges becomes

Six similar bulbs are connected as shown with a DC source of emf E and zero internal resistance. The ratio of power consumed when (i) all glow to (ii) when two of section A and one of section B glow, is:

The reading of an ideal voltmeter in the circuit shown is:

In the two circuits shown (same 10 V cell, same 10 $\Omega$ resistor; ideal meters, only the order of V and A swapped), the readings of the voltmeters and ammeters will be:

Which of the following acts as a circuit protecting device?

A metre bridge is balanced with P/Q = l$_{1}$/l$_{2}$. If the positions of galvanometer and cell are interchanged, will it balance, and what is the condition?

For a p-type semiconductor, which of the following statements is true?

The circuit diagram shown here corresponds to the logic gate:

An LED is constructed from a p-n junction diode using GaAsP. The energy gap is 1.9 eV. The wavelength of the light emitted will be equal to:

The correct Boolean operation represented by the circuit diagram drawn (an LED Y driven from +6 V through resistor R with inputs A and B) is:

Two similar thin equi-convex lenses of focal length f each are kept coaxially in contact with each other such that the focal length of the combination is F₁. When the space between the two lenses is filled with glycerin (which has the same refractive index, µ = 1.5, as that of glass) then the equivalent focal length is F₂. The ratio F₁ : F₂ will be

An equiconvex lens has power P. It is cut into two symmetrical halves by a plane containing the principal axis. The power of one part will be:

In total internal reflection, when the angle of incidence is equal to the critical angle for the pair of media in contact, what will be the angle of refraction?

A double convex lens has focal length 25 cm. The radius of curvature of one of the surfaces is double that of the other. Find the radii if the refractive index of the material of the lens is 1.5:

A cycle wheel of radius 0.5 m is rotated with constant angular velocity of 10 rad/s in a region of magnetic field of 0.1 T which is perpendicular to the plane of the wheel. The EMF generated between its centre and the rim is,

A 800 turn coil of effective area 0.05 m² is kept perpendicular to a magnetic field 5 × 10⁻⁵ T. When the plane of the coil is rotated by 90 degrees around any of its coplanar axis in 0.1 s, the emf induced in the coil will be:

The variation of EMF with time for four types of generators are shown in the figures. Which amongst them can be called AC?

In which of the following devices, the eddy current effect is not used?

The radius of the first permitted Bohr orbit for the electron in a hydrogen atom is 0.51 Å and its ground state energy is –13.6 eV. If the electron in hydrogen is replaced by a muon (μ⁻) [charge same as electron, mass 207 mₑ], the first Bohr radius and ground state energy will be:

The total energy of an electron in an atom in an orbit is –3.4 eV. Its kinetic and potential energies are, respectively:

In hydrogen atom, the de Broglie wavelength of an electron in the second Bohr orbit is: [Given Bohr radius a₀ = 52.9 pm]

In a double slit experiment, when light of wavelength 400 nm was used, the angular width of the first minima formed on a screen placed 1 m away, was found to be 0.2°. What will be the angular width of the first minima, if the entire experimental apparatus is immersed in water? (n_water = 4/3)

The angular width of the central maximum in the Fraunhofer diffraction for λ = 6000 Å is θ₀. When the same slit is illuminated by another monochromatic light, the angular width decreases by 30%. The wavelength of this light is

In a Young's double slit experiment, if there is no initial phase difference between the light from the two slits, a point on the screen corresponding to the fifth minimum has path difference

Ionized hydrogen atoms and α-particles with same momenta enter perpendicular to a constant magnetic field B. The ratio of the radii of their paths rₕ : r_α will be:

A straight conductor carrying current i splits into two parts as shown in the figure. The radius of the circular loop is R. The total magnetic field at the centre P of the loop is:

A cylindrical conductor of radius R is carrying a constant current. The plot of the magnitude of the magnetic field B with the distance d from the centre of the conductor is correctly represented by the figure:

A proton and an α-particle are accelerated from rest to the same energy. The de Broglie wavelengths λ_p and λ_α are in the ratio:

The work function of a photosensitive material is 4.0 eV. The longest wavelength of light that can cause photoemission from the substance is (approximately):

An electron is accelerated through a potential difference of 10000 V. Its de Broglie wavelength is, (nearly): (mₑ = 9 × 10⁻³¹ kg)

Two metal spheres, one of radius R and the other of radius 2R respectively have the same surface charge density σ. They are brought in contact and separated. What will be the new surface charge densities on them?

Two identical capacitors C1 and C² of equal capacitance are connected as shown. Terminals a and b of key k are connected to charge capacitor C1 using a battery of emf V. Now disconnecting a and b, the terminals b and c are connected. Due to this, what will be the percentage loss of energy?

A parallel plate capacitor of capacitance 20 µF is being charged by a voltage source whose potential is changing at the rate of 3 V/s. The conduction current through the connecting wires and the displacement current through the plates of the capacitor would be, respectively,

For a transparent medium the relative permeability and permittivity µ_r and ε_r are 1.0 and 1.44 respectively. The velocity of light in this medium would be

A circuit when connected to an AC source of 12 V gives a current of 0.2 A. The same circuit when connected to a DC source of 12 V, gives a current of 0.4 A. The circuit is