#### 12th Standard English Medium Physics Reduced syllabus Creative Three mark Question with Answerkey - 2021(Public Exam )

12th Standard

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Physics

Time : 01:00:00 Hrs
Total Marks : 75

3 Marks(Creative)

25 x 3 = 75
1. Define potential difference and derive.

2. Derive an expression for electric flus in a non uniform electric field and an arbitrarily shaped area.

3. What is dielectrics or insulators.

4. (a) Distinguish between electric cells and batteries.
(b) Explain its function

5. Find the expression for the equivalent emf & internal resistance of the series combination of cells

6. What are the types of magnets? Give example.

7. Mention the properties of Magnetic field lines?

8. Write the expression in a vector from for the (i) Lorentz magnetic force $\vec { F }$ due to a charge moving with velocity $\vec { v }$ in a magnetic field $\vec { B }$ What is the direction of force. (ii) If the magnetic force $\vec { F }$ acting an it is non-zero would the particle gain any energy?

9. A given galvanometer is to be converted into (i) an ammeter (ii) a voltmeter. In which case will the required resistance be (i) least (ii) highest and why?

10. Give and explain the mechanical analogy of LC oscillations by qualitative treatment.

11. What is impedance? When does LCR circuit have minimum impedance?

12. Write the uses of Infrared radiation

13. How does Ampere - Maxwell law expalain the flux of current trough a capacitor when it is being charged by a battery? write the expression for the displacement current in terms of the rate of change of electric flux.

14. Write the difference between paraxial rays and marginal rays.

15. Write three characterists features in photoelectric effect which cannot be explained on the basis of wave theory of light, but can be explained only using Einstein's equation.

16. The graph shows the variation of stopping potential with frequency of incident radiation for two photosensitive metals A and B. Which one of the two has higher value of workfunction? Justify your answer.

17. The figure shows a plot of three curves a, b, c showing the variation of photocurrent vs. Collector plate potential for three different intensities I1,I2, and I3having frequencies v1' v2 and v3 respective incident on a photosensitive surface.
The figure shows a plot of three curves a, b, c showing the variation of photocurrent vs. Collector plate potential for three different intensities I1,I2, and I3 having frequencies v1,v2 and v3 respective incident on a photosensitive surface.

18. What is the diameter of H2 atom?

19. Digine atomic mass unit. Find its energy equivalent in MeV

20. With respect to power generation, what are the relative advantages and disadvantages of fusion type and Fission type reactors?

21. Write the two ways of preparing the nano materials

22. What is electronics?

23. Write the limitations of FM.

24. Why space wave propagation is limited upto small distance over earth's surface?

25. Why ground wave cannot be used for long distance communication using high frequency?