CBSE Guess > Papers > Important Questions > Class XII > 2013 > Physics > Physics - by Mr. Raghu Sharma
CBSE CLASS XII
Physics
- distance of separation between the slits and the screen is doubled?
- Calculate the ratio of energies of photons produced due to transition of electron of hydrogen atom from its,
- Second permitted energy level to the first level, and
- Highest permitted energy level to the second permitted level
- Give expression for the average value of the a c voltage V = V0 Sin t over the time interval t = 0 and t =
- How is the band gap, Eg, of a photo diode related to the maximum wavelength, m , that can be detected by it?
- Define mobility. What is its S.I unit?
- Two electric bulbs are marked 220V, 60W and 220V, 100W. Which of the two bulbs has greater resistance? Why?
- What is the value of angle of dip at a place on the surface of the earth, where the horizontal component of earth’s magnetic field is 0.5 times the resultant field at the place?
- An a.c. generator generates an emf ‘e’ given by: e = 311 sin (100 pt) volt. Find the rms value of the emf generated by the generator.
- A rectangular wire frame, shown below, is placed in a uniform magnetic field directed upward and normal to the plane of the paper. The part AB is connected to a spring. The spring is stretched and released when the wire AB has come to the position A’B’ (t=0). How would the induced emf vary with time? Neglect damping.
- What is the ratio of speed of g-rays and radio waves in vacuum?
- Two nuclei have mass numbers in the ratio 1:8. What is the ratio of their densities?
- The stopping potential obtained in an experiment on photoelectric effect is 2.5 V. What is the value of maximum kinetic energy of the electrons emitted from the metal?
- Can two equi-potential surfaces intersect each other? Explain.
- (b)Two charges – q and + q are located at points A (0, 0, -a) and B (0, 0, +a)
- respectively. How much work is done in moving a test charge 2 µC from
- point P (7, 0, 0) to Q (-3, 0, 0)?
- Explain what is meant by quantization of charge and conservation of charge, also give the important property of charge ?
- State and explain coulomb’s law, give the vector form of coulomb law.
- Explain the concept of electric field . give the relation between electric field strength and force.
- Derive expression for electric field intensity at a point due to a point charge.
- Derive an expression for dipole field intensity at any point on
- axial line
- equatorial line of dipole.
- Derive an expression for torque acting on electric dipole in a uniform electric field
- Derive an expression for potential energy of an electric dipole in a uniform electric field.
- Derive an expression for potential at a point due to point charge and due to an electric dipole.
- State gauss’s theorem in electrostatics . how will u prove it for spherically symmetric surfaces.
- Using gauss’s theorem , derive an expression for electric field intensity at a point due to a
- line charge
- a uniformly charged spherical shell
- an infinite plane sheet of charge
- Explain the term electric field intensity .electric field inside conductor is zero. Explain.
- A force F experienced by a particle of charge q moving with velocity v in a magnetic field B is given by
. Which pair of vectors is always at right angles to each other?
- The closed loop PQRS is moving into uniform magnetic field acting at right angles to the plane of the paper as shown in the figure. State the direction in which the induced current flows in the loop.
- Sketch the out put from a NAND gate having inputs A and B as shown following
Submitted By : Mr. Raghu Sharma
Email: [email protected]
