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Q10. A. Describe the relationship between frictional resistance and: (i)Ship speed; (ii) the wetted area; (iii) surface roughness; (iv) The length of the vessel.  B.A ship travels at 15 knots and has a QPC of 0.865 with a delivered power of 2600 KW. The apparent slip is 5% and the real ship is 28%Calculate the total resistance and the wake friction.

Q6.a) Explain the applications of PN junction diode. (6)

b) A full-wave, 1 -phase rectifier employs a double diode valve, the internal resistance of each element of which may be assumed constant at 500 W. The transformer r.m.s. secondary voltage from the centre-tap to each anode is 300 V and the load has a resistance of 2000 W.  Evaluate:-   (10)

(i) mean load current.

(ii) r.m.s. value of load current

(iii) the d.c. output power

(iv) the input power to the anode circuit

(v) the rectification efficiency

Q10. (A) Compare the effectiveness of a current limiting circuit breaker with that of a HRC fuse. (6)

(B) Evaluate for a frequency of 15 kHz, the amplification and the phase difference between input and output signals of a voltage amplifier using a triode having an amplification factor of 48 and a mutual conductance of 1.2 mA/V with an anode-load resistant of 160 k𝛀. The output p.d. is fed by a coupling capacitor of negligible reactance to a subsequent circuit of resistance 480 k𝛀 and the total shunt capacitance is 90 µF. (10)

Q9. a) Describe briefly the inclining experiment and explain how the results are used. (6)

b) A ship of 14900 tonne displacement has a shaft power of 4460 KW at 14.55 knots. The shaft power is reduced to 4120 Kw and the fuel consumption at the same displacement is 541 kg/h. Calculate the fuel coefficient for the ship. (10)

Q7. (a) What are the various resistances acting against the motion of the ship? (6)

(b) A vessel of 10000 t displacement burns 25 t of fuel per day when her speed is 12 Knots. Calculate the probable consumption of fuel over a voyage of 3000 nautical miles at a speed of 11 knots with a displacement of 11000 t. (10)

Q7. A ship of 6400 t displacement is floating in salt water. The ship has to proceed to a berth where the density of the water is 1008 kg per cubic meter. Find how much cargo must be discharged if she is to remain at the salt water draft. (16)

Q6. a) State why cargo ships must have collision bulkheads. (6)

b) A double bottom tank is 1.2 m deep and has a sounding pipe extending 11 m above the tank top. The tank is filled with oil (rd 0.89) to the top of the sounding pipe. The double bottom floors are spaced 750 mm apart and are connected to the tank top by riveted angles, the rivets having a pitch of 7 diameters. If the maximum allowance stress in the rivets is 30 MN/m2, calculate the pressure in kN/m2 on the outer bottom and the diameter of the rivets. (10)

Q9. a) Explain Fleming's Right hand rule. (6)

b) A one-turn armature coil has an axial length of 0.4m and a diameter of 0.2m. It is rotated at a speed 500 rev/min in a field of uniform flux density of 1.2 T. Calculate the magnitude of the e.m.f. induced in the coil. (10)

Q9. A wooden ring having a mean diameter of 200 mm and a cross-sectional area of 400 mm2 is wound uniformly with a coil of 300 turns. If the current passed through the coil is 5 A calculate the value of flux produced in the coil. (16)

Q8. (a) Explain how fluorescent tubes power factor is improved. (6)

(b) A fluorescent lamp taking 80W at 0.7 power factor lagging from a 230V, 50-Hz supply is to be corrected to unity power factor. Determine the value of the correcting approach required. (10)

Q7. (a) Define Density, Relative Density (6)

(b) A bilge holding tank of 5 m length, 3 m width and 1.8 m depth has water of density 1.020 t/m3 up to a sounding of 1.3 m and oil of density 0.86 t/ m3 is floating on top of water up to an ullage of 0.3 m. Calculate the mass of water and oil in the tank. (10)

Q8. (a) Derive the formula for Admiralty Coefficient. (6)

(b) A ship travels 900 nautical miles at a speed of 12.5 knots and burns 150t of fuel over the voyage. Estimate the distance the ship could travel at a speed of 13.5 knots on 250t of fuel. (10)