QUESTION PAPER 10

1. (a) What are A.C and D.C voltages? State advantages of A.C over D.C. (7)
(b) Explain Faraday’s law and Lenz law of electromagnetic induction. (7)
2. (a) Derive an expression for equivalent resistance for the resistors connected in series and
in parallel. (7)
(b) Three resistors are connected to form the sides of a triangle ABC. The resistance of side
AB is 40 Ω, side BC is 60Ω and side CA is 100Ω. Calculate the effective resistance
between the points A and B. (7)
3. (a) Explain various stages of generation of static electricity in detail. (7)
(b) What are precaution will you take against electrostatic hazards. (7)
4. (a) Explain the principle, construction and working of A.C. generator with necessary
diagrams. (7)
(b) Draw the constructions of DC motor, series type D.C motor and shunt type D.C
motor. (7)
5. (a) 48 lamps each having a resistance of 220Ω are connected in parallel across 220V.
Determine
(i) power consumption in watt and
(ii) cost of operating lamps for 24 hours at Rs.1/- per kwh. (7)
(b) A capacitor of 20μF is charged up to 500 V is connected in parallel with another
capacitor of 10 μF which is charged up to 200 V. Determine the common potential of
the capacitors. (7)
6. (a) Explain Earth as a magnet. (7)
(b) Describe various magnetic elements due to earth’ s magnetic field. (7)
7. (a) Explain in detail ship magnetism and its various components. (7)
(b) Calculate the total field of the earth at a place where the value of angle of dip is 30˚
and H=0.48 gauss. (7)
*****