QUESTION PAPER 4

Note: Attempt any FIVE questions. All carry equal marks.
1. (a) Describe an Earth as a magnet. (5 marks)
(b) What are semiconductors? Explain P-type and n-type semiconductors. (5 marks)
(c) Show the circuits of diode in Forward and reverse bias. (5 marks)
2. (a) Distinguish among soft and hard magnetic materials. (5 marks)
(b)Do iron ships pose particular problems for magnetic compass and why? (5 marks)
(c) What are precautions to be taken while handling non-conductive containers. (5 marks)
3. Explain in detail the circuits of half wave , full wave and bridge rectifier s along with necessary
circuit diagrams , waveforms. Also state advantages and disadvantages of each one them.
(15 marks)
4. How transistors are formed. What are there type? Show the circuits of different modes of connection of a transistors. What are α and β of a transistor. Derive relation between them.
(15 marks)
5. (a) Explain Faraday’s and Lenz’s law of electromagnetic induction (5 marks)
(b) State the principle of D.C motor. Show the constructional details of D.C motor (5 marks)
(c) What is photo transistor? State applications of photo transistor (5 marks)
6. (a) What are optoelectronic devices? Explain LED and TDR (5 marks)
(b) Draw a logic circuit to display the number”7” in seven segment display (5 marks)
(c) Show the constructional details of A.C generator (5 marks)
7. Derive an expression for a current flowing through A.C circuit containing
(a) Resistor only,
(b) Capacitor only and (c) Inductor only. (15 marks)
8. Write a short note on :
(a) Filter capacitor in rectifier circuit (5 marks)
(b) Nuclear chain reaction (5 marks)
(c) The magnetic compass (5 marks)
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