Physics Pre-Test Examination 2024 - Girdih

A pair of equal and opposite charges separated by a small distance.

The SI unit of dipole moment is Coulomb-meter (C-m).

The equivalent capacitance (Ceq) of three capacitors connected in parallel is the sum of their individual capacitances: Ceq = C + C + C = 3C.

The electric field (E) is the negative rate of change of electric potential (V) with respect to distance (x).

Decreasing the distance between the plates of a parallel plate capacitor reduces its capacitance.

Current density (J) is the product of the charge density (ne) and the drift velocity (V).

The magnetic field inside a toroidal solenoid is independent of the radius of the torus. It depends on the number of turns and the current flowing.

The magnetic lines of force inside a bar magnet travel from the north pole to the south pole.

Lenz's law is based on the principle of conservation of energy. It states that an induced current always opposes the change in magnetic flux that caused it.

Two parallel conductors carrying current in the same direction will attract each other, while currents in opposite directions repel.

Self inductance is similar to inertia in mechanics. It opposes any change in the current flowing through a coil.

A transformer works only for alternating current (AC). It cannot work for direct current (DC).

In an AC circuit with only inductance, the current lags behind the voltage by a phase angle of 90 degrees.

Gamma rays are a type of electromagnetic radiation used in the treatment of cancer.

The Balmer series of the hydrogen spectrum lies in the visible region of the electromagnetic spectrum.

A mirror with a magnification of 1.5 is a concave mirror.

The refractive index of a medium is minimum for red light.

Diffraction of light cannot be explained through ray optics. It requires wave theory.

The length of an astronomical telescope in normal adjustment is the sum of the focal lengths of the objective lens (fo) and the eyepiece (fe).

Huygens' wave theory cannot explain the photoelectric effect. This effect can only be explained by the quantum theory of light.

According to de Broglie hypothesis, the wavelength of a matter wave is inversely proportional to its momentum (mv).

The radius of the second Bohr orbit is four times the radius of the first Bohr orbit.

A substance with a forbidden energy gap of 1 eV is a semiconductor.

Doping silicon with indium creates a P-type semiconductor.

When a reverse bias is applied to a p-n junction, it raises the potential barrier, reduces the majority carrier current to zero, and increases the depletion layer width.

An electric dipole is an arrangement of two equal and opposite charges separated by a small distance.

Gauss's theorem states that the total electric flux through a closed surface is proportional to the enclosed charge.

The SI unit for magnetic flux is Weber (Wb).

The average value of alternating current (AC) for half a cycle is zero.

Electromagnetic waves in the visible region are used for eye surgery.

Increasing the distance between the slits in a double-slit experiment will cause the width of the interference fringes to decrease.

Threshold frequency is the minimum frequency of light that can eject electrons from a metal surface.

Nuclear forces are extremely strong, short-range forces that bind protons and neutrons within the nucleus. They are independent of charge.

The depletion layer in a p-n junction is a region near the junction where there are very few free charge carriers.