CBSE Physics Model Question Paper- IV
1. Define solar constant.
Answer
2. Give two uses of polaroids.
Answer
3. Why electric intensity inside a charged conductor is zero?
Answer
4. Cyclotron is not suitable to accelerate electrons. Why?
Answer
5. What is Zener voltage?
Answer
6. What is de-Broglie wavelength of a particle of mass m at rest?
Answer
7. What is the difference between mass number and atomic weight?
Answer
8. What are full forms of QUASARS and PULSARS?
Answer
9. A thin prism of 6° angle gives a deviation of 3°. What is the refraction index of the prism?
Answer
10. What is de-Broglie wavelength of an electron accelerated across a potential difference V volt?
Answer
11. Why is A.C. preferred to D.C.?
Answer
12. What is meant by blue shift? What would have been the state of universe had there been blue shift? “
Answer
13. What is capacitance of a conducting slab? Explain with reasoning.
Answer
14. What is temperature coefficient of resistance? Name one substance each with positive, negligible and negative temperature coefficient of resistance?
Answer
15. Find half life period of a radioactive material if its activity drops to (1/32) of its value of 37.5 years.
Answer
16. Why does the sun appear reddish at the time of sunrise and sunset?
Answer
17. Derive a relation for the energy stored in a capacitor,
Answer
18. How can OR gate be realised from NAND gate.
Answer
19. Eleven wires each of resistance 4 Q are joined to form an open skelton cube. Find the resistance across open end of the cube.
Answer
20. What is drift velocity? Derive a relation between drift velocity and electric intensity.
Answer
21. Derive an expression for fringe width in an interference pattern.
Answer
22. What is transformer? Describe its working. Show that whatever is gained in voltages is lost in current and vice versa.
Answer
23. Derive an expression for self inductance of a coil of n turns wound on a card board with iron core.
Answer
24. A galvanometer has a resistance of 50 Q gives a full scale deflection for a current of 0.05 A. Calculate the length of a shunt wire required to convert the galvanometer into an ammeter of range 0-5 A. The diameter of shunt wire is 2 mm and its resistivity is 5 X 10-7 ohm m.
Answer
25. What are isotopes, isobars and isotones? Give one example each to illustrate your answer.
Answer
26. Derive a relation for the distance which T.V. signals can directly be received from T.V. tower of height/?.
Answer
27. What is angle of dip? Where is it 0° and 90°? How can you determine the angle of dip without placing dip circle in magnetic meridian?
Answer
28. Describe a D.C. motor. What is the role of back e.m.f. in it? Determine the efficiency of a D.C. motor. When is it maximum?
Define electric potential energy. Derive an expression for it on system of N point charges.
Answer
29. Explain amplification action of a transistor. How a PNP transistor can be used as an amplifier with common emitter configuration 7 which one is preferred, a common base or common emitter amplifier? Give reasons for your answer.
Answer
30. Describe Millikan’s oil drop method to determine the charge on an electron. What is the importance of electronic charge determination?
Answer