Goa Board Class 12 Question Paper Mar 2019 Auto Electricals

2019 III 14 1000 Seat No.

Time : 2 Hours AUTO ELECTRICALS
Subject Code

V 3 7 2
Total No. of Questions : 5 (Printed Pages : 3) Maximum Marks : 50

INSTRUCTIONS : (i) Answer each question on fresh page.

(ii) Write the main question numbers and sub question

numbers clearly.

(iii) Figures to the right indicate full marks.

(iv) All questions are compulsory.

(v) Illustrate your answers with neat labelled diagram

wherever necessary.

1. (A) Answer the following questions in one sentence each :

(1) Name the component which is known as power source of an

electrical system. 1

(2) Write down the chemical reaction which takes place during the

discharge of lead acid battery. 1

(3) What is the function of heat sink in an alternator ? 1

(4) Explain the role of ‘‘Regulator Rectifier’’ unit in two wheeler. 1

(5) In a micro spark plug word ‘‘W175Z1’’ is punched on the shell of

the spark plug. What does ‘‘175’’ stand for ? 1

(6) Why is Charging coil used in an ‘‘Electronic Ignition System ?’’ 1

(B) How will you Inspect the magneto visually and test the magneto for
its A.C. output by using multimeter ? 4

2. (A) Answer the following questions in short :

(1) Explain the procedure to charge the lead acid battery by using
‘‘constant voltage charging method.’’ 2

(2) Explain the working of coil type voltage regulator used in charging
system. 2

(3) Draw a neat labelled diagram of ‘‘Hydrometer.’’ 2

(B) How will you test the following components of an Ignition system by
using multimeter : 4

(a) High tension coil.

(b) Capacitor.

3. (A) Answer the following questions in short :

(1) What are the requirements of good Ignition system ? 2

(2) State the four advantages of ‘‘Sealed beam head light’’ over the
conventional head light. 2

(3) Draw a neat labelled diagram of ‘Armature of Generator.’’ 2

(B) Write the functioning of the following units :

(a) Neutral switch. 2

(b) Solenoid switch. 2

4. (A) State four causes and suggest remedies for the following troubles :

(1) Low output from Alternator. 2

(2) Starter armature fails to rotate or rotates slowly. 2

(3) ‘‘Engine fails to start’’, due to faulty Ignition system. 2

(B) With the help of neat labelled diagram, explain the working of
‘‘Standard Bendix drive.’’ 4

5. (A) Answer the following questions in short :

(1) Draw a neat labelled circuit diagram of ‘‘delta-connected stator in

alternator with six diodes.’’ 2

(2) Explain the working of, ‘‘central locking system’’ in a car. 2

(3) How does horn relay play an important role in double horn ? 2

(B) With the help of neat labelled circuit diagram explain the working of
‘‘Balancing coil type of oil pressure gauge.’’ 4