Search

Saturday 17 August 2013

Marine Electrical numericals solved


1. If resistance of any coil is 120 OHM. Calculate the resistance when its length is increased by 20% and its dia is increased by 50 % ( fill in the blank)
Ans  64 ohm

2. A certain appliances uses 750w. if it is allowed to run continuously for 15 days how many kilowatt of energy does it consume? (fill in the blank)
Ans  240 KW

3. What is the mageto motive force in a 75 turn coil of wire when there are 4 amp of current through it
(fill in the blank)
Ans 300

4. If it takes 35 jule of energy to move a charge of 6C from one point to another what is the voltage betn the two points (fill in the blank)
Ans  5.83

5. Calculate the velocity of conductor if terminal voltage is 2.2 v/m & the magnetic field strength is 0.2T (fill in the blank)
Ans  11 m/s
6. Calculate the frequency of the motor if the speed is 4800 rpm & no of poles are 2
(sometime speed is given in RPS)
Ans  80 Hz
7.What is the power in a resistance in mili volt having resistance of 12 ohm having a potential difference of 3v (fill in the blank)
Ans  750 kw
8. What is the max allowable primary current of 2kva step down transformer with a 4-1 turns ratio if connected across a 440 v line (uscg optional)
Ans  4.5 amps
9. A 40 cm wire current of 20 amp is placed in a uniform magnetic field of 0.6 the wire make an angle of 30 degree cal the magnitude of force on wire (fill in the blank)
Ans  2.4
10. Find the voltage of a motor of 200 rpm when the flux changes from 1wb to 4wb (fill in the blank)
Ans  600 V
11.Calculate avg value of 12 v peak sign wave for one complete cycle
Ans  complete cycle = 0
       Half cycle = 0.637 X Vpr
12. Inductance or capacitance (don’t remember but the unit is same) is 6mh current go from 0.4 to 2.5 amp in 0.6 sec calculate emf (up to 3 decimal places) (fill in the blank)
Ans  0.021
13. A sine wave with RMS value of 100 V is riding on a DC level of 50 V. calculate the maximum value of the resulting wave form.
Ans  191
14. A half wave rectifier having a resistive load of 600 ohm
with supply voltage of 80 v and having forrowed resistance
of 100 ohm. calculate the peak current.
Ans  0.161 amps
15.The type of the system whose transfer function is given by 
G(S) =(s2+3)/(s5+s4+s3+3s2+2s) is:
Ans  1
16.. Alfa particles enter an electromagnetic field where the electric intensity is 300v/m and the magnetic induction is 0.200T what is the velocity of alfa particles?
Ans  1500 m/s
17.Calculate the frequency of the motor if the speed is 400 RPS and no. of poles is 2.
Ans  400 Hz        

18.the voltage induced across a certain coil is 150 mV. A 100 ohms resistor is connected to the coil terminal. calculate the induced current in milli amps.
Ans   1.5 ma
19. If the resistance of the wire is 15 ohms if length is doubled and dia is one third, then resistance of the wire is???
Ans  270
20. what is the maximum allowable primary current of a 2kva step down transformer with 4:1 turn ratio , if connected across a 440 v line?
Ans  4.5

21. If the flux through 120 turn coil changes steadily from 2wb to 6 wb in 1 second. what is the voltage induced??
Ans  480

22. A 20 m wire carrying a current of 10 Amps magnetic field of 0.3 T with an angle of 40 degrees with vector B. Find the magnitude of force?
Ans 38.56

23. Three resistors 40,50,60 connected in series input 30 V . Calculate voltage drop across 60 resistor.
Ans  12v/h

24. The armataure resistance of a 200 V d.c. machine has 0.5 ohm. If the full load armature current is 50 A, what will be the induced e.m.f. when, the machine acts as (i) generator (ii) motor will be 

(a) 230 V, 170 V (b) 210 v, 190 v, (c)
225 V, 175 C (d)202.5 V, 197.5 V

25. When 3H and 2H are in series and 2H is the mutual inductance .. what is effective inductance?
Ans  9


No comments:

Post a Comment