CBSE Guess > Papers > Important Questions > Class XII > 2013 > Physics > Physics - by Mr. Raghu Sharma
CBSE CLASS XII
Physics
- The energy of an electron in n th orbit is given by En =
eV. Calculate the energy required to excite an electron from ground state to the second excited state.
- Which of the following has the shortest wavelength: microwaves, ultraviolet rays and X-rays.
- What will happen to the image formed by a mirror if half of it is covered with a black paper?
- The frequency of AC is being increased in a circuit containing bulb and a capacitor in series. How will the brightness of the bulb be affected?
- Derive an expression for electric potential on the axis of a dipole.
- A cylindrical metallic wire is stretched to increase its length by 5%. Calculate the percentage change in its resistance.
- Define resistivity and conductivity of a conductor. Write their SI units.
- Draw graph for ohmic and non ohmic conductor. Write one example of each.
- What is the dielectric constant of a conductor?
- Two protons are entering a magnetic field perpendicular to the magnetic field with velocities in the ration 1:2. What is the ratio of their angular frequencies?
- A magnetic field exits along –ve z-axis .coil A is kept with the magnetic field with the plane of the coil in the x-y plane and coil b is kept with the plane of the coil in x-z plane. In which coil will there be no induced emf when magnetic field varies with time?
- Write the relationship between amplitudes of electric and magnetic field in free space for an electromagnetic wave.
- A converging lens and a diverging lens are kept in contact and the combination produces a real image. Which of the lens has longer focal length?
- Maximum kinetic energy of electron emitted by metal A is 4ev and metal B is 5ev. Which metal has greater work function when exposed to same radiation?
- 23Ne10 decay by b emission to 23Na11 .write down the decay equation.
- An electric dipole of dipole moment 20 X 10-6 Cm is enclosed by a closed surface. What is the net flux coming out of the surface?[1]
- Which orientation of a magnetic diploe in a uniform magnetic field will correspond to its stable equilibrium?[1]
- Draw a graph to show the variation of capacitive reactance with frequency of an a.c. source.[1]
- Which part of electromagnetic spectrum has largest penetrating power?[1]
- Draw a graph showing the variation of intensity of polarized light transmitted by the analyser.[1]
- Name the experiment, which establishes the wave nature of a particle.[1]
- State two properties of nuclear forces.[1]
- Write the truth table for the combination of gates shown here.[1]
- A charge q is placed at the center of the line joining to equal charges Q. Show that the system of three charges will be in equilibrium if q=-Q/4.
Submitted By : Mr. Raghu Sharma
Email: [email protected]
