Page 104 - Physics - XI

17. Note down the increased volume of air in AB.

18. Note down the mercury level in CD.
19. Lower down CD further by about 2 cm and repeat the above steps.
20. Repeat the previous steps a few more times.

Observations and Calculations
Room Temperature
Room temperature at the beginning of experiment, t = ______ °C
1
Room temperature at the end of experiment, t = ______ °C
2
t + t 100 P 100 P
Mean temperature, T = 1 2 = ______ °C 90 90
2 X 1 80 Q X 1 80 Q
Mean of Atmospheric Pressure 70 X 2 70
60 60
Atmospheric pressure at the beginning of experiment, 50 50
H = ______ cm of Hg 40 40
1
30
30
Atmospheric pressure at the end of experiment, H = ______ 20 20
2
cm of Hg Fig. 3.5: Observation for correction
H + H in mercury level
Mean Atmospheric Pressure, H = 1 2 ______ cm of Hg
2
Correction in Level of Mercury due to curved portion of tube AB
Reading at the top end of tube, AB = x = ______ cm
1
Reading at the beginning of curved portion of tube AB = x = ______ cm
2
1
Correction = (x – x ) = ______ cm
3 1 2
Alternately, correction can also be calculated by using

l = 1 r where, r = radius of tube
3
Table for calculation of the diameter of the wire

Position of Hg Level Pressure Diff erence Pressure of Air Volume 1 PV
–3
(p) (cm) P = Z + p of air V (cm )
In Tube AB In Tube CD (cm) 0 V
3
(cm) Tube AB – Tube CD (cm of Hg) (cm )

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