NEET 2019

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

\(\alpha\)-particale consists of :

A parallel plate capacitor of capacitance 20 \(\mu\)F is being charged by a voltage source whose potential is changing at the rate of 3V/s. The conduction current through the connecting wires, and the displacement current through the plat...

Body A of mass 4m moving with speed u collides with another body B of mass 2 m, 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 :

In the circuits shown below, the readings of voltmeters and the ammeters will be :

Which of the following acts as a circuit protection device?

Six similar bulbs are connected as shown in the figure with a DC source of emf E, and zero internal resistance.
The ratio of power consumption by the bulbs when (i) all are glowing and (ii) in the situation when two from section A and one...

An electron is accelerated through a potential difference of 10,000 V. Its de Broglie wavelength is (nearly) : (me = 9 \(\times\) 10–31 kg)

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

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

Which colour of the light has the longest wavelength?

Two parallel infinite line charges with linear charge densities +\(\lambda\) C/m and -\(\lambda\) 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 hollow metal sphere of radius R is uniformly charged. The electric field due to the sphere at a distance r from the centre :

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

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 sam...

Pick the wrong answer in the context with rainbow.

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 angle of refraction?

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

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

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

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

A block of mass 10 kg is in contact against the inner wall of a hollow cylindrical drum of radius 1 m. The coefficient of friction between the block and the inner wall of the cylinder is 0.1. The minimum angular velocity needed for the cyli...

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

At a point A on the earth’s surface the angle of dip, \(\delta\) = + 25o. At a point B on the earth's surface the angle of dip, \(\delta\) = – 25o. We can interpret that :

When an object is shot from the bottom of a long smooth inclined plane kept at an angle 60o with horizontal, it can travel a distance x1 along the plane. But when the inclination is decreased to 30o and the same object is shot with the same...

A particle moving with velocity
\(\overrightarrow V\) is acted by three forces shown by the vector triangle PQR. The velocity of the particle will :

The speed of a swimmer in still water is 20 m/s. The speed of river water is 10 m/s and is 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 st...

Ionized hydrogen atoms and \(\alpha\)-particles with same momenta enters perpendicular to a constant magnetic field, B. The ratio of their radii of their paths rH : r\(\alpha\) will be :

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

Average velocity of a particle executing SHM in one complete vibration is :

The radius of circle, the period of revolution, initial position and sense of revolution are indicated is the figure.

y- projection of the radius vector of rotating particle P is :

The displacement of a particle executing simple harmonic motion is given by
y = A0 + A sin\(\omega\)t + B cos\(\omega\)t.
Then the amplitude of its oscillation is given by :

A soap bubble, having radius of 1 mm, is blown from a detergent solution having a surface tension of 2.5 \(\times\) 10–2 N/m. The pressure inside the bubble equals at a point Z0 below the free surface of water in a container. Taking g = 1...

A copper rod of 88 cm and an aluminium rod of unknown length have their increase in length independent of increase in tmperature. The length of aluminium rod is : (\(\alpha\)Cu = 1.7 × 10–5 K–1 and
\(\alpha\)Al = 2.2 × 10–5 K–1)

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 unit of thermal conductivity is :

A small hole of area of cross-section 2 mm2 present near the bottom of a fully filled open tank of height 2 m. Taking g = 10 m/s2, the rate of flow of water through the open hole would be nearly :

A disc of radius 2 m and mass 100 kg rolls on a horizontal floor. Its centre of mass has speed of 20 cm/s. How much work is needed to stop it?

A solid cylinder of mass 2 kg and radius 4 cm is rotating about its axis at the rate of 3 rpm. The torque required to stop after 2\(\pi\) revolutions is :

Two particles A and B are moving in uniform circular motion in concentric circles of radii rA and rB with speed vA and vB respecitively. Their time period of rotation is the same. The ratio of angular speed of A to that of B will be :

The correct Boolean operation represented by the circuit diagram drawn is :

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

In an experiment, the percentage of error occurred in the measurement of physical quantities A, B, C and D are 1%, 2 %, 3 %and 4 % respectively. Then the maximum percentage of error in the measurement X, where
X = $${{{A^2}{B^{1/2}}} \over...

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 1m away, was found to be 0.2o. What will be the angular width of the first minima, (\(\mu\)water = 4/3) ...

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