List of top Questions asked in UP Board XII

Explain the meaning of binding energy of a nucleus. Write the dependency of binding energy per nucleon on the mass number of the nucleus.
Give pictorial representation of polarized and unpolarised light. Polarizing angle for a transparent medium is 60°. Find the value of angle of refraction and refractive index of the medium.
Name the waves of longest wavelength and highest frequency in the given electromagnetic waves — microwaves, X-rays, radio waves, and \(\gamma\)-rays. What is meant by displacement current?
What is the meaning of stationary orbit of atom? Deriving formula for the energy of the electron in the stationary orbit of the hydrogen atom, mention its relation with the radius of the orbit of electron.
What is an astronomical telescope? Draw ray diagram for an astronomical telescope when final image is formed at infinity.
State Gauss's law in electrostatics. On the basis of it, obtain the formula for the electric field produced due to a plane charged plate.
Do two equipotential surfaces intersect each other? Answer with reason.
On which principle does a nuclear reactor work?
What is the meaning of electrical capacity of a conductor? Find the unit of the electrical capacity of the conductor.
On connecting a cell of e.m.f. 0.5 volt with an external resistance of 1.9 $\Omega$, the current flowing is 0.75 A. The internal resistance of the cell is:
Write down Einstein's equation for the photoelectric effect.
Write de-Broglie formula for the wavelength of matter waves.
Equation of electric field of a plane electromagnetic wave is given as:
\[ E_z = 60 \sin(500x + 1.5 \times 10^{11} t) \, \text{V/m}. \] Write the equation for the magnetic field of the wave.
In an alternating circuit, the reading of the voltmeter is 220 V. Write the peak value of the voltage.
Explain the meaning of rectification. Using a p-n junction diode, draw a circuit diagram of a full-wave rectifier and give a brief description of its working. Give a graphical representation of input and output voltage/current.
A charge \( q \) enters with speed \( v \) in the direction of magnetic field \( B \). The force on the charge in magnetic field will be:
Electrostatic force between two point charges placed in a medium of dielectric constant \( k \) is \( F_1 \). On changing the medium, electrostatic force between the charges becomes \( F_2 \). Dielectric constant of the medium will be:
A concave lens of focal length -18 cm is placed in contact with a convex lens of focal length +12 cm. The focal length of the combination will be:
Resistance of an ideal p-n junction diode in reverse bias is:
Resistivity of a conducting wire depends on:
With the help of a suitable ray diagram, derive the formula \( \frac{1}{v} + \frac{1}{u} = \frac{1}{f} \) for a concave mirror.
Write Huygens' principle of secondary wavelets and explain the laws of refraction of light on its basis.
Explain the difference between interference and diffraction of light. Write the expression for the width of interference fringes in Young's double slit experiment and explain the effect of separation of slits and wavelength of light used on it.
Which nature of light is supported by the phenomenon of photoelectric effect? Write Einstein's equation related to photoelectric emission and briefly explain the laws of photoelectric emission on its basis.
What is the meaning of nucleon? What is the mass number of nucleus? Write down the relation between mass number and radius of nucleus and show that the density of nucleus does not depend on mass number.