IGNOU Test Papers - BNS103 Electricity and Electronics - December 2005

B.Sc. NAUTICAL SCIENCE

Term-End Examination

June, 2005

BNS-103: ELECTRICITY AND ELECTRONICS

Time: 2 hours
Maximum Marks : 70

Note :
(i) Non-programmable scientific calculator may be used.
(ii) Attempt three questions each from Section A and Section B. Q. No.1 and 5 are compulsory.

SECTION A (Electricity)

1. (a) Explain navigation lights with necessary circuit diagram. (5)

(b) Explain principle, construction and working of moving coil galvanometer. (5)

(c) A galvanometer resistance 100 Ω has 100 divisions. When a potential difference of 20 mV is applied to its terminal, it deflects by 10 divisions. How can it be converted into a voftmeter to read 100 volts ? (5)

Attempt any two from the following three.

2. (a) State and explain Kirchhoff's voltage law.(5)

(b) Two cells of emfs 6V and 8V having internal resistances of 0.5 Ω and 1 Ω respectively are connected in parallel. External resistance of 4 Ω is connected across the combination. Find the terminal voltage of each cell. (5)

3. (a) Explain series RLC circuit with its phasor diagram. Discuss the conditions for series resonance.(5)

(b) The force per unit length between two long parallel conductors is 1.5 x 10^-4 N/m. The conductor spacing is 10 cm. If one conductor carries twice the current of the other, calculate the current in each conductor. (5)

4. (a) Explain principle, construction and working of d.c. generator. (5)

(b) A 100 μF capacitor in series with a 40 Ω resistor is connected to a 110 V, 60 Hz a.c. supply. (5)

(i) What is the current in the circuit ?
(ii) What is the time lag between current and voftage ?

SECTION B (Electronics)

5. (a) Explain CB amplifier using NPN transistor with necessary circuit diagram. (10)

(b) The collector supply voltage in a common emitter amplifier is 8V. The voltage drop across the load resistance of 1.4 kΩ is 1.4 V. If α of the tansistor is 0.92, determine
(i) Collector to emitter voltage
(ii) Base current (5)

Attempt any two from the following three.

6. (a) Explain capacitor filter with necessary circuit diagram. (5)

(b) A half wave rectifier is used to supply 50 V d.c. to a load of 800 Ω. The forward resistance of the diode is 25 Ω. Calculate the rms value of a.c. voltage required. (5)

7. (a) What is demodulation? Explain AM diode detector with circuit diam. (5)

(b) An AM wave is represented by the expression
V = 35 (1 + 0.5 cos 1200 t) sin 314 x 10⁴t volts. (5)

(i) What are the maximum and minimum amplitudes of the AM wave ?
(ii) What frequency components are contained in the modulated wave ?

Test Papers / Previous Question Papers of IGNOU BNS103 Electricity and Electronics December 2005