Goa Board Class 12 Question Paper June 2018 Electronics Materials and Workshop Practice

2018 VI 08 1430 Seat No. :

Time : 2 Hours ELECTRONICS MATERIALS AND
WORKSHOP PRACTICE

Subject Code

V 3 3 2

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

INSTRUCTIONS : i) Answer each question on a fresh page.
ii) Write the number of the question and sub-question clearly.
iii) All questions are compulsory.
iv) Figures to the right indicate full marks.
v) Draw a neat labelled diagram wherever necessary.

1. A) Fill in the blanks : [2]
i) The insulating material used to manufacture radio circuit capacitor, commutator
segment, domestic appliances is ___________.
ii) A solution of a resinous material in oil, turpentine or alcohol is called _________.
B) Answer the following : [6]
i) State any six essential rules and methods required for repairing of an appliance.
ii) Mention any one application of the following tools :
a) Bench vice
b) Combination insulated plier
c) Double end open jaw spanner
d) Cross peen hammer
e) Round file
f) Series test lamp.
State any four advantages of PCB.

V-332 -1- P.T.O.

2. A) Answer the following : [2]
i) Write any two properties of Nichrome.
ii) State two ways to minimise hysteresis loss.
B) Answer the following : [6]
i) State any four properties and two applications of Germanium.
ii) Draw a neat labelled flow chart for manufacturing process of a PCB.
State any four properties of Epoxy laminates.

3. A) Fill in the blanks : [2]
i) The high resistivity material used for making different types of rheostats,
resistance wires, resistance boxes is ____________.
ii) The magnetic material used to manufacture machine yokes, electrical
magnetic brakes is ______________.
B) Answer the following : [3]
State any two applications of the following insulating materials :
a) Porcelain
b) Insulating tapes
c) PVC.
C) Answer any one of the following in detail : [5]
i) With the help of a neat labeled diagram, explain the construction of type A
mechanically biased dry reed relay.
OR
ii) With the help of a neat labeled diagram, explain the construction of general
purpose relay.

4. A) Answer the following in brief : [2]
i) Write any two applications of thermocouple.
ii) Draw a neat labeled diagram of hysteresis loop.
B) Answer the following : [3]
Write any two applications of the following conducting materials :
a) Aluminium b) Tungsten c) Selenium

V-332 -2-

C) Answer any one of the following in detail : [5]
i) With the help of a neat labeled diagram, explain zone refining method of
semiconductor crystal growth.
OR
ii) With the help of a neat labeled diagram, explain Czochralski method of
semiconductor crystal growth.

5. Answer the following : [10]
i) State any four properties of Alnico.
ii) Draw a neat labeled diagrams for the following :
a) Resistance measurement using voltmeter Ammeter method.
b) Open circuit fault by test lamp.
iii) Distinguish between conductor and insulator (Mention two points each).
iv) What is Lubricant ? Name any two types of Lubricants.
v) State any four sequential steps for dismantling of an appliances.

_______________

V-332 -3- P.T.O.