List of top Questions asked in UP Board XII

State and prove Ampere's circuital law.
Explain the meaning of polarisation of light and show the difference between polarised and unpolarised light with the help of a suitable diagram.
Write the unit of electric flux.
Define electromotive force of a cell.
Self-inductance of a coil is 6 mH and the rate of flow of current in it is $10^3$ A/s. Find the induced emf produced in the coil.
Mention the major drawbacks of Rutherford's atomic model.
In a single-slit diffraction pattern, the angle of diffraction for the second minimum is $60^\circ$. Find the width of the slit in terms of $\lambda$.
To measure potential difference from a galvanometer, we connect in it:
In electromagnetic waves, phase difference between electric and magnetic field vectors is:
Prism angle of a prism is $A$ and angle of minimum deviation is equal to prism angle. Refractive index of the material of prism will be:
The unit of magnetic dipole moment is
Threshold wavelength for a metal surface is 2000 \AA. On incidence of radiation of 1000 \AA, the kinetic energy of emitted photoelectrons will be
Charge on a piece of metal is \(-3.2\) coulomb. Number of excess electrons in the metal is:

Find the values of \( x, y, z \) if the matrix \( A \) satisfies the equation \( A^T A = I \), where

\[ A = \begin{bmatrix} 0 & 2y & z \\ x & y & -z \\ x & -y & z \end{bmatrix} \]

 How much charge is there on a hole? Draw the circuit symbol of p-n junction diode. 
 

Describe the importance of seed and fruit development.

Find the minimum value of  ( z = x + 3y ) under the following constraints: 

• x + y ≤ 8
• 3x + 5y ≥ 15
• x ≥ 0, y ≥ 0

Four alternatives are given in each part of this question. Choose the correct alternative and write it in your answer-book. Number of moles in 180 g of water is:
The unit of velocity constant for a first-order reaction is:
Appropriate reagent used to distinguish between acetaldehyde and acetone is
(a) If orders of matrices A and B are \( p \times q \) and \( q \times r \) respectively, then order of AB is:
Find the principal value of \( \sin^{-1} \left( \sin \frac{7\pi}{4} \right) \).
Write short notes on the changes in atomic and ionic sizes and ionization enthalpy of transition metals.
(d) If vectors \( \mathbf{5i - \lambda j + 2k} \) and \( \mathbf{2i + 3j + 4k} \) are perpendicular, find \( \lambda \):

A charge \( Q \) is distributed over two concentric hollow spheres of radii \( r \) and \( R \) (\( R>r \)) such that their surface charge densities are equal. Find the electric potential at their common center.