### PHYSICS PRACTICAL PROCEDURE

Physics practical procedure for class 12 students to do the practical.

LINEAR RESISTANCE OF A GIVEN WIRE

AIM:  To determine resistance per cm i.e linear resistance of a given wire by plotting a graph of potential difference versus current.
APPARATUS:  A resistance wire, a voltmeter, an ammeter, a battery, a rheostat, a meter scale, a one-way key, and connecting wire.
FORMULA:
The resistance of given wire   R = V/i   ohm
Where V – Voltage applied in volt  and i – Current through the wire in ampere
Linear resistance of given wire    σ = R/l

GRAPH: TABULAR FORM FOR UNKNOWN RESISTANCE:

 S.No The voltage across the wire            V in volt Current through the wire               I   in amp Resistance        R = V/I     in ohm 1   2   3   4   5   6

RESULT:
The graph between V and i is a straight line and linear resistace of the wire
σ = _______ohm/cm.

COMPARING THE EMFs OF TWO GIVEN PRIMARY CELLS

AIM: To compare the EMFs of two given primary cells using a potentiometer.
APPARATUS:  Potentiometer, battery, two cells ( a Leclanch cell and a Daniel cell), rheostat, resistance box, a one-way key, a two-way key, a jockey, and connecting wires.
FORMULA:
E1/E2 = l1/ l2

Where E1 and E2 are EMFs of the two given cells and l1 and l2 are corresponding balancing lengths on potentiometer wires.
CIRCUIT:

TABULAR FORM:

S.No.

Current
I    in amp
 Balancing point (length) in cm For E1 For E2

E1/E2 = l1/ l2

RESULT:
EMFs of two cells are compared.

The ratio of EMFs of given cells    E1/E2 = l1/ l2 =