List of top Physics Questions asked in UP Board XII

Which type of field is produced around a current carrying conductor and why?
The equivalent resistance of 5 equal resistances connected in series and parallel are \( R_1 \) and \( R_2 \) respectively. If \( R_1 = nR_2 \), then what will be the possible value of \( n \)?
Which of the following is the unit of electric flux?

Write down Einstein's photoelectric equation. Photons of energies 1 eV and 2.5 eV respectively are incident on a metal plate of work function 0.5 eV. If maximum kinetic energies of emitted photoelectrons are \( k_1 \) and \( k_2 \) respectively and their velocities are \( v_1 \) and \( v_2 \), then find the magnitudes of (i) \( k_1/k_2 \) and (ii) \( v_1/v_2 \).

What are the Bohr's Postulates for the hydrogen atom? Write down the following for electrons in the ground state of hydrogen atom:
(i) Binding energy
(ii) Angular momentum
(iii) Total energy

A wire is stretched to double of its original length. The value of its resistivity becomes:
Explain the differences between \( n \)-type and \( p \)-type semiconductors. Show that both types of semiconductors are electrically neutral.
Discuss the characteristics of (i) forward biasing and (ii) reverse biasing in \( p\)-\(n \) junction. Explain the cause of origin and direction of current in both conditions.
Obtain the formula for the intensity of electric field on the equatorial point of an electric dipole.
What is Gauss' law? Find the formula for the intensity of electric field produced due to a point charge with the help of it.
Explain refraction of light by Huygens wave theory, when waves enter from denser to rarer medium.
The equivalent capacitance is 20 \( \mu \)F by joining two capacitors of capacitances \( C_1 \) \( \mu \)F and \( C_2 \) \( \mu \)F in parallel. If they are joined in series, the equivalent capacitance is 4.8 \( \mu \)F. Find the ratio of the capacitances \( C_1 \) and \( C_2 \) ( \( C_1>C_2 \)).
When does the force acting between two parallel and straight current carrying conductors become (i) attractive and (ii) repulsive and why?
What is displacement current? A plane electromagnetic wave of 25 MHz frequency is propagating along the x-axis in vacuum. The electric field at any point in the vacuum is \( \vec{E} = 6 \hat{j} \) volt/metre. What is the magnitude and direction of the magnetic field \( \vec{B} \) at this point?
Define mass defect and binding energy.
Write the definition and unit of current density.
Obtain the formula of the relationship of drift velocity and potential difference.
What is meant by angle of polarisation?
Define 1 henry of self-inductance.
Find the ratio of de-Broglie wavelength associated with a proton and an \( \alpha \)-particle having the same kinetic energy.
Threshold wavelength for a photoelectric cell is \( \lambda_0 \). If the work-function of the cathode of some other cell becomes \( n \) times that of the first cell, then threshold wavelength for the other cell will be:
In order to pass 10\% of the main current in a galvanometer of resistance \( R \), the required resistance of shunt should be:
The unit of \( \sqrt{LC} \) (where \( L \) is inductance and \( C \) is capacitance) is:
In the given nuclear process, particle \( W \) is: \[ ^2\text{He}^4 + _zX^A \rightarrow _{z+2}Y^{A+3} + W \]
What are the microwaves? State one use of them.