NEET 2017 Physics Questions

A rope wound on a hollow cylinder of mass 3 kg and radius 40 cm is pulled with a force of 30 N. The angular acceleration of the cylinder is:

Which of the following statements are correct? (a) The centre of mass of a body always coincides with its centre of gravity. (b) The centre of mass is the point where the total gravitational torque on the body is zero. (c) A couple on a body produces both translational and rotational motion. (d) Mechanical advantage greater than one means a small effort can lift a large load.

Two discs of equal moment of inertia I, rotating about their common axis with angular speeds w1 and w2, are brought face-to-face into contact (axes coinciding). The loss of energy in the process is:

Two blocks A and B of masses 3m and m respectively are connected by a massless inextensible string. The whole system is suspended from a massless spring as shown. The magnitudes of the accelerations of A and B immediately after the string is cut are, respectively:

One end of a string of length l is connected to a particle of mass m and the other end to a small peg on a smooth horizontal table. If the particle moves in a circle with speed v, the net force on the particle (directed towards the centre) is (T = tension in the string):

A spring of force constant k is cut into lengths in the ratio 1 : 2 : 3. These pieces are first connected in series, giving force constant k′, and then in parallel, giving force constant k″. The ratio k′ : k″ is

A particle executes linear simple harmonic motion with an amplitude of 3 cm. When the particle is at 2 cm from the mean position, the magnitude of its velocity equals the magnitude of its acceleration. Its time period (in seconds) is

Two rods A and B of different materials are welded together side by side as shown in the figure. Their thermal conductivities are K₁ and K₂. The effective thermal conductivity of the composite rod (for heat flowing from the left face at T₁ to the right face at T₂) will be:

A spherical black body of radius 12 cm radiates 450 W power at 500 K. If the radius were halved and the temperature doubled, the power radiated (in watt) would be:

The acceleration due to gravity at a height 1 km above the earth equals that at a depth d below the surface. Then:

Two astronauts are floating in gravitational free space after losing contact with their spaceship. The two will:

The figure shows a $P$-$V$ diagram with three isotherms at $700$ K, $500$ K and $300$ K. Four processes I, II, III and IV start from a common initial state. Match each process with its type:\\ List-I (Process): I, II, III, IV\\ List-II (Type): (a) Adiabatic, (b) Isobaric, (c) Isochoric, (d) Isothermal.\\ Which of the following is the correct matching?

A Carnot engine having an efficiency of $\dfrac{1}{10}$ as a heat engine is used as a refrigerator. If the work done on the system is $10$ J, the amount of energy absorbed from the reservoir at lower temperature is

Preeti reached the metro station and found that the escalator was not working. She walked up the stationary escalator in time $t_1$. On other days, if she remains stationary on the moving escalator, then the escalator takes her up in time $t_2$. The time taken by her to walk up on the moving escalator will be:

The $x$ and $y$ coordinates of a particle at any time $t$ are $x=5t-2t^2$ and $y=10t$ respectively, where $x$ and $y$ are in metres and $t$ in seconds. The acceleration of the particle at $t=2$ s is:

Consider a drop of rain water having mass 1 g falling from a height of 1 km. It hits the ground with a speed of 50 m/s. Take g constant with a value 10 m/s². The work done by the (i) gravitational force and the (ii) resistive force of air is

A physical quantity of the dimensions of length that can be formed out of c, G and e²/(4πε₀) is [c is velocity of light, G is universal constant of gravitation and e is charge]:

A gas mixture consists of 2 moles of O₂ and 4 moles of Ar at temperature T. Neglecting all vibrational modes, the total internal energy of the system is:

The bulk modulus of a spherical object is B. If it is subjected to uniform pressure p, the fractional decrease in radius is

Two nearest (successive) harmonics of a tube closed at one end and open at the other are 220 Hz and 260 Hz. The fundamental frequency of the system is:

A U-tube with both ends open to the atmosphere is partially filled with water. Oil, which is immiscible with water, is poured into one side until it stands at a distance of 10 mm above the water level on the other side. Meanwhile the water rises by 65 mm from its original level (see figure). The density of the oil is:

The ratio of resolving powers of an optical microscope for two wavelengths λ₁ = 4000 Å and λ₂ = 6000 Å is

Young's double slit experiment is first performed in air and then in a medium other than air. It is found that 8th bright fringe in the medium lies where 5th dark fringe lies in air. The refractive index of the medium is nearly

Two Polaroids P₁ and P₂ are placed with their axes perpendicular to each other. Unpolarised light I₀ is incident on P₁. A third polaroid P₃ is kept in between P₁ and P₂ such that its axis makes an angle 45° with that of P₁. The intensity of transmitted light through P₂ is

The diagrams (a), (b), (c), (d) below show regions of equipotentials (with values 10 V, 20 V, 30 V, 40 V arranged differently). A positive charge is moved from A to B in each diagram. Which statement is correct?

A capacitor is charged by a battery. The battery is removed and another identical uncharged capacitor is connected in parallel. The total electrostatic energy of resulting system

The given electrical network (with inputs A, B and output Y) is equivalent to:

Which one of the following represents a forward biased diode?

An arrangement of three parallel straight wires placed perpendicular to the plane of paper carrying the same current 'I' along the same direction is shown in the figure. The magnitude of the force per unit length on the middle wire 'B' is given by:

A 250-turn rectangular coil of length 2.1 cm and width 1.25 cm carries a current of 85 A and is subjected to a magnetic field of strength 0.85 T. The work done for rotating the coil by 180° against the torque is:

A beam of light from a source L is incident normally on a plane mirror fixed at a certain distance x from the source. The beam is reflected back as a spot on a scale placed just above the source L. When the mirror is rotated through a small angle θ, the spot of light is found to move through a distance y on the scale. The angle θ is given by

A thin prism having refracting angle 10° is made of glass of refractive index 1.42. This prism is combined with another thin prism of glass of refractive index 1.7. This combination produces dispersion without deviation. The refracting angle of the second prism should be

The resistance of a wire is R. If it is melted and stretched to n times its original length, its new resistance is:

A potentiometer is an accurate and versatile device to measure emf because the method involves:

The photoelectric threshold wavelength of silver is 3250 × 10⁻¹⁰ m. The velocity of the electron ejected from a silver surface by ultraviolet light of wavelength 2536 × 10⁻¹⁰ m is (Given h = 4.14 × 10⁻¹⁵ eV·s and c = 3 × 10⁸ m/s):

The de Broglie wavelength of a neutron in thermal equilibrium with heavy water at a temperature T (kelvin) and mass m is:

The ratio of wavelengths of the last line of Balmer series and the last line of Lyman series is:

Suppose the charges of a proton and an electron differ slightly. One of them is −e, the other is (e + Δe). If the net of the electrostatic force and the gravitational force between two hydrogen atoms placed at a distance d (much greater than atomic size) apart is zero, then Δe is of the order of [Given: mass of hydrogen mₕ = 1.67 × 10⁻²⁷ kg]

In an electromagnetic wave in free space the root mean square value of the electric field is E_rms = 6 V/m. The peak value of the magnetic field is

A 250-turn rectangular coil of length 2.1 cm and width 1.25 cm carries a current of 85 A and is in a magnetic field of strength 0.85 T. The work done in rotating the coil by 180° against the torque is:

A long solenoid of diameter 0.1 m has 2 × 10⁴ turns per meter. At the centre of the solenoid, a coil of 100 turns and radius 0.01 m is placed with its axis coinciding with the solenoid axis. The current in the solenoid reduces at a constant rate to 0 A from 4 A in 0.05 s. If the resistance of the coil is 10 π² ohm, the total charge flowing through the coil during this time is