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| Post Office box |
POST
OFFICE BOX
Aim:-
A post
office box and other necessary instruments are given to you. Take three
appropriate ratios of the resistances in the two arms of Post Office Box and
determine the values of two unknown resistances.
Now
connect the unknown resistances in series and parallel respectively and verify
the laws of series and parallel combinations of resistances.
PRINCIPLE
:-
It works
on the principle of balanced Wheatstone bridge.
APPARATUS
:-
A
Battery,
unknown
resistance (Rx & Ry),
Post
Office Box,
a
galvanometer,
rheostat,
connecting
wires
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| Post office box Apparatus |
CONDITION
1 :-
Connect
unknown resistance Rx between C and D
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| Post office line diagram condition 1 |
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| Post office condition 1 Practical |
CONDITION 2 :-
Connect
unknown resistance Ry between C and D
 |
| Post office line diagram condition 2 |
 |
| Post office condition 2 practical |
CONDITION
3 :-
Connect
unknown resistance Rx & Ry in SERIES
between C and D
 |
| Post office series connection |
 |
| Post office series connection practical |
CONDITION
4 :-
Connect
unknown resistance Rx & Ry in PARALLEL
between C and D
 |
| Post office parallel connection condition 4 |
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| Post office box parallel connection |
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| Post office box observation table |
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| Post office box calculations |
Precautions
(1) All
plug keys of Post Office Box must be tight.
(2) Contact points of K1 and K2 must
be cleaned with sand paper.
(3) Galvanometer should be very sensitive.
(4) Throughout the experiment press key K2(battery key) first
and then key K1(galvanometer key).
For more details view Video.
For more details view Video.
POST OFFICE BOX
