CBSE Class 12 Physics Sample Paper 2015 Set G

1. Two identical charged particles moving with same speed enter a region of uniform magnetic field. If one of these enters normal to the field direction and the other enters along a direction at 300 with the field, what would be the ratio of their angular frequencies?

2. Why does a metallic piece become very hot when it is surrounded by a coil carrying high frequency alternating current?

3. How is a sample of an n-type semiconductor electrically neutral though it has an excess of negative charge carriers?

4. Name the characteristics of electromagnetic waves that (i) increases (ii) remains constant in the electromagnetic spectrum as one moves from radiowave region towards ultraviolet region.

5. How would the angular separation of interference fringes in Young’s double slit experiment change when the distance of separation between the lists and the screen is doubled?

6. Calculate the ratio of energies of photons produced due to transition of electron of hydrogen atom from its,

(i) Second permitted energy level to the first level, and

(ii) Highest permitted energy level to the second permitted level.

7. Give expression for the average value of the a c voltage V = V₀Sinw t over the time interval t = 0 and t = π/ w.

8. How is the band gap, Eg, of a photodiode related to the maximum wavelength, lm that can be detected by it?

9. Keeping the voltage of the charging source constant, what would be the percentage change in the energy stored in a parallel plate capacitor if the separation between its plates were to be decreased by 10%?

10. Explain how the average velocity of free electrons in a metal at constant temperature, in an electric field, remain constant even though the electrons are being constantly accelerated by this electric field?

11. How is the resolving power of a microscope affected when,

(i) the wavelength of illuminating radiations is decreased?

(ii) the diameter of the objective lens is decreased? Justify your answer.

12. What is the basic difference between the atom or molecule of a diamagnetic and a paramagnetic material? Why are elements with even atomic number more likely to be diamagnetic?

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