List of top Questions asked in Bihar Board Class XII

Reverse biased diode is
Boolean expression of NAND gate is
What type of wave is used in fibre optic communication?
If two converging lenses of equal focal length \(f\) are kept in contact, then the focal length of the combination will be
Power of a convex lens is 2 dioptre. Its focal length will be
Which of the following is used to reduce chromatic aberration in lenses?
A convex lens is dipped in a liquid, whose refractive index is equal to the refractive index of the material of the lens. Then its focal length will
The bubble of soap appears coloured due to
Which of the following cannot be polarized?
A person uses spectacles (lens) of +2D power. His defect of vision is.
In polarised light the angle between plane of vibration and plane of polarization is
Which of the following is not an electromagnetic wave?
The speed of electromagnetic wave in any material medium does not depend on.
In the phenomenon of photoelectric emission, on increasing the intensity of incident light, the photoelectric current
The wavelength of de Broglie wave associated with any moving particle does not depend on
The formula of kinetic mass of photon is
The speed of an electron accelerated from rest under a potential difference \( V \) is
The specific charge of an electron is
In parallel combination of condensers, which quantity remains same for each condenser?
On inserting a dielectric material between two positive charges in air, the value of repulsive force will
The distance between two equal and opposite charges of \( 0.2 \mu C \) will be 3.0 cm. Their electric dipole moment will be
Inside a closed surface, n electric dipoles are situated. The electric flux coming out from the closed surface will be
Two light waves of equal amplitude and equal wavelengths are superimposed. The amplitude of the resultant wave will be maximum when phase difference between them is
In a purely inductive circuit, the power factor is
In an a.c. circuit containing only capacitor, the phase difference between current and voltage is