Goa Board Class 12 Question Paper Mar 2018 Electronic Material _ Workshop Practice _New Pattern_

2018 III 08 1000 Seat No. :

Time : 2 Hours ELECTRONICS MATERIALS AND WORKSHOP PRACTICE
(New Pattern)
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 neat labelled diagrams wherever necessary.

1. A) Fill in the blanks : [2]
i) The residual flux density on the hysteresis loop is called as __________
ii) The type of varnish used to prepare laminations of mica and glass is _________
B) Answer the following : [6]
i) State any two applications of the following conducting materials :
a) Nichrome
b) Copper
c) Carbon
ii) Draw neat labelled Energy Band Diagrams for conductors, semiconductors
and insulators.
C) Answer the following : [2]
Draw a neat labelled diagram of mechanically biased Dry Reed Relay and
state its two applications.

2. A) Define the following terms : [2]
i) Breakdown voltage
ii) Dielectric strength.
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B) Answer the following : [6]
i) Draw a neat diagram of hysteresis loop and explain the terms hysteresis
loss and magnetostriction.
ii) State any one application of each of the following tools :
a) Standard Screw Driver
b) Firmer Chisel
c) Adjustable Wrench
d) Long Nose Plier
e) Tennon Saw
f) Ball Peen Hammer.
C) Answer the following : [2]
Draw a neat labelled diagram of General Purpose Relay.

3. A) Fill in the blanks : [2]
i) The cutting tool used for filing corners having angles less than 90°
is _______
ii) The magnetic material used for manufacturing current transformers
is __________
B) Answer the following : [3]
State any three applications of the following semiconductor materials :
a) Silicon
b) Germanium.
C) Answer any one of the following in detail : [5]
i) With the help of a neat labelled diagram explain the Horizontal Bridgman
method of semiconductor crystal growth and purification.
OR
ii) With the help of a neat labelled diagram explain the Liquid Phase Epitaxy
method of crystal growth and purification of semiconductor crystal.

4. A) Answer the following in brief : [2]
i) Name the high resistivity material that is used to manufacture photoelectric
cells, safety devices and light meters.
ii) What is a lubricant ?

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B) Answer the following : [3]
With the help of neat labelled diagrams explain any two types of Mass Soldering
Techniques.
C) Answer any one of the following in detail : [5]
i) State any ten points of necessary arrangement for upkeeping of Assembly
Shop.
OR
ii) State any ten points of personal safety precautions of Assembly Shop.

5. Answer the following : (5×2=10)
i) State any two advantages and disadvantages of Phenolic Laminates.
ii) State any four applications of PVC.
iii) Explain the construction of Bimetallic Relay.
iv) State any four advantages of PCB.
v) Write any four steps of overhauling of an appliance or a motor.

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