NEET Practice Test - 7 - NEET MCQ

The upper half of an inclined plane with inclination ϕ is perfectly smooth while the lower half is rough. A body starting from rest at the top will again come to rest at the bottom if the coefficient of friction for the lower half is

The Bohr radius of the fifth electron of phosphorous atom (atomic number = 15) acting as a dopant in silicon (relative dielectric constant = 12) is ___________ Å.

A black body is at a temperature of 2880 K. The energy of radiation emitted by this body with wavelength between 499 nm and 500 nm is U₁, between 999 nm and 1000 nm is U₂ and between 1499 nm and 1500 nm is U₃. The Wien's constant, b = 2.88 × 10⁶ nm K. Then,

Find out the expression for the magnetic field at a point on the centre of a coil of radius carrying current I and having N number of turns.

A ball kept in a closed box moves in the box making collisions with the walls. The box is kept on a smooth surface. The centre of mass

One slit of a double slit experiment is covered by a thin glass plate of refractive index 1.4, and the other by a thin glass plate of the refractive index 1.7. The point on the screen where the central maximum fall before the glass plate was inserted, is now occupied by what had been the fifth bright fringe was seen before. Assume the plate have the same thickness tt and wavelength of light is 480 nm. Then the value of t is

A trolley of mass 300 kg carrying a sand bag of 25 kg is moving uniformly with a speed of 27 km/h on a frictionless track. After a while, sand starts leaking out of a hole on the floor of trolley at the rate of 0.05 kg/s. What is the speed of the trolley after the entire sand bag is empty

A cyclist starts from the centre O of a circular park of radius 1 km, reaches the edge P of the park, then cycles along the circumference and returns to the centre along QO as shown. If the round trip takes 10 min, what is the (a) net displacement, (b) average velocity and (c) average speed of the cyclist (in km/hr)?

The work function for a certain metal is 4.2 eV. What is the energy difference between the work function & energy photon for incident radiation of wavelength 330 nm ?

A particular hydrogen like atom has its ground state binding energy = 122.4  eV. It is in ground state. Then,

In an L-R circuit connected to a battery of constant emf E switch S is closed at time t = 0. If e denotes the induced emf across inductor and i the current in the circuit at any time t. Then which of the following graphs shows the variation of e with i?

A particle of mass m carrying a positive charge q moves simple harmonically along x-axis under the action of a varying electric field E directed along x-axis. The motion of the particle is confined between x = 0 and x = 2l. The angular frequency of the motion is ω. Then, which of the following is correct?

A infinite line charge produces a field of 9 × 10⁴ N/C at a perpendicular distance of 2 cm. The linear charge density is

Two positive charges of 12 μC and 8 μC are placed 10 cm apart in air. The work done to bring them 4 cm closer is

A 100 eV electron is fired directly towards a large metal plate having surface charge density –2 × 10⁶ C m^–2. The distance from where the electron is projected so that just fails to strike the plate is

A free alpha particle and a free proton are separated by distance of 10^–10 m and are released. The kinetic energy of alpha particle when at infinite separation is

An assembly of charges +q, –q, +q, –q, … are at positions x = 1 m, 2 m, 4 m, 8 m, … respectively from origin. The electric potential due to these charges at origin is

Two positive charges Q₁ and Q₂ are fixed at A and B. A unit positive charge is taken from A to B along the line joining AB. The force experienced by unit charge

A uniform circular ring of radius R has charge Q distributed uniformly over it. A charge q is placed at the centre of the ring. What is increase in tension in the ring?

Three point charges of 1C, 2C and 3C are placed at the corners of an equilaterals triangle of side 1 m. What is work required to move these charges to the corners of smaller equilateral triangle of side 0.5 m?

The insulation property of air breaks down at E = 3 × 10⁵ V/m. The maximum charge that can be given to a sphere of radius 3 m is

27 small mercury droplets each of radius R and charge q are combined to form a big drop. The ratio between the potentials of bigger drop to smaller drop is

The electric potential at a point due to electric dipole will be maximum and minimum when angles between the axis of dipole and line joining the point to the dipole axis are respectively

A parallel plate capacitor with air between plates has capacity of 1 pF. Now plates are moved apart with insulating handle so that separation is twice of original value. The space between plates is filled with a medium of dielectric constant 6. The new value of capacity in pF is

The capacitance of spherical capacitor is 1 μF. If the separation between the two spherical shells is 1 mm. The radius of outer shell is nearly

A parallel plate capacitor has each plate area A and separation d. Charge Q is given to positive plate of capacitor. The force on each plate of capacitor is

A parallel plate capacitor is charged and then battery is disconnected. The effect of increasing the plate separation on charge, potential and capacitance respectively is