CBSE 12 Physics Question Paper-2025 Set-6

Two horizontal plates, separated by 1 cm, are arranged one above the other. A particle of mass 5 mg and charge 2 nC is released in air between the plates. The potential difference that should be applied to the plates so that the particle remains suspended between them, is:

A rectangular coil of area A is kept in a uniform magnetic field $\vec{B}$ such that the plane of the coil makes an angle a with $\vec{B}$. The magnetic flux linked with the coil is:

An alternating current is expressed as $I=I_{0}cos(100\pi)t|$. The minimum time taken by the current to change from its maximum value to zero is:

The electric field (E) and electric potential (V) at a point inside a charged hollow metallic sphere are respectively:

The dimensions of 'self-inductance' are:

In a circular loop of radius R, current I enters at point A and exits at point B, as shown in the figure. The value of the magnetic field at the centre O of the loop is:

Frequency of a photon of energy 1.326 eV is:

Germanium crystal is doped at room temperature with a minute quantity of boron. The charge carriers in the doped semiconductors will be :

A steady current I is passed through a conductor at room temperature for time t. It is observed that its temperature rises by $0.5^{\circ}C$. If 2I current is passed through the conductor (at room temperature) for the same duration, the rise in its temperature will be approximately:

Isotones are nuclides which have:

A proton and an a-particle, with the same kinetic energy, enter a region of uniform magnetic field perpendicularly. The ratio of their radii of the circular paths will be:

The photoelectric effect can be explained by assuming that:

The half-life of a radioactive substance is 20 days. What is the time taken for 3/4 of its original mass to disintegrate?

If the value of shunt resistance connected across a galvanometer is 1/n times the resistance of the galvanometer, then the fraction of the total current passing through the galvanometer is:

The energy of an electron in the nth orbit of a hydrogen atom is given by Eₙ = -13.6/n² eV. The ratio of the energies of an electron in the first and third excited states is:

The threshold wavelength for a metal with a work function of 6.63 eV will be:

The ratio of the speed of an electron in the first Bohr orbit of a hydrogen atom to the speed of light in vacuum is:

In a series LCR circuit, the voltage across resistance, capacitance, and inductance is 10 V each. If the capacitor is short-circuited, the voltage across the inductance will be:

In a cyclotron, the velocity of a charged particle is independent of the:

The current in a coil changes from 10 A to 2 A in 0.1 s. If the average induced emf in the coil is 40 V, then the coefficient of self-inductance of the coil is:

A light ray enters from air to a medium of refractive index 1.5. The speed of light in the medium is:

If the electric and magnetic fields are E and B respectively, then the ratio of the energy densities is:

The ratio of the intensity of magnetisation (I) to the magnetising field (H) is known as: