List of top Questions asked in UP Board XII

Draw the logic symbol of a NOR gate and write its truth table.
Obtain the formula for the electric potential on the axial line of an electric dipole.
The work function of a metal is \( 2.5 \times 10^{-9} \) joule. If the metal is exposed to a light beam of frequency \( 6.0 \times 10^{14} \) Hz, what will be the stopping potential?
The net resistance of an ammeter should be small to ensure that:
Define optical centre of a lens.
As compared to \(^{12}_6C\) atom, how many extra protons and neutrons does the \(^{14}_6C\) atom have?
How much energy is released in mass defect of 1 amu?
The electric field of intensity \( \vec{E} = (3 \hat{i} + 4 \hat{j}) \, \text{N/C} \) passes through the plane of area \( \vec{A} = (10 \hat{i}) \, \text{m}^2 \). Find the electric flux.
Write the minimum orbital angular momentum of the electron in a hydrogen atom.
In a transistor:
The equivalent resistance of the network shown in figure between A and B is:
What is the meaning of wavefront? Explain the laws of reflection by explaining Huygens' principle of wavefront.
The equation \( E = pc \), where \( E \), \( p \), and \( c \) represent energy, momentum, and velocity of light, is valid:
What is LED? Explain its principle, construction and working.
As the temperature of a metal and of a semiconductor is increased, the:
What do you understand by electromagnetic induction? State Faraday’s laws regarding electromagnetic induction.
Explain both the laws of Kirchhoff of electrical circuits.
Obtain the formula for refractive index of material of prism in terms of angle of minimum deviation and angle of prism.
What is the meaning of matter-wave of Louis de Broglie? Deduce the relation for wavelength of de Broglie in terms of kinetic energy.
Derive the formula for the capacitance of a parallel plate capacitor, partially filled with a dielectric.
Explain Bohr's model of the atom.
The energy of an electron of excited hydrogen atom is -3.4 eV. Determine the angular momentum of the electron.
Define the formula for the resonant frequency in a series L-C-R alternating current circuit.
What is a transistor? By drawing the circuit diagram of common emitter configuration, plot the output characteristics.
What are meant by ohmic and non-ohmic resistances? Draw the graph between voltage and current for a non-ohmic circuit and define dynamic resistance.