Page 154 - Physics - XI

7. Least count of metre scale = _________ cm

8. Area of cross-section of pipes A and B

d 2
Pipe A, a = r 1 =_________
2
1
1
4
d 2
Pipe B, a = r 2 = _________
2
2 2
4
9. Density of water, ρ = 1g cm –3
10. Acceleration due to gravity, g = 980 cm/s 2

Area of cross- Area of cross- Height of Height of water Pressure Pressure
S. section of section of water in tube in tube inside pipe A, inside pipe B,
No.
pipe A (cm ) pipe B (cm ) C, h (cm) D, h (cm) P = ρgh P = ρgh
2
2
1 2 1 1 2 2
1.
2.

3.

Result

The pressure of fl uid (water) decreases (height of water decreasing) when the velocity of water increases
at the narrow cross-section and vice-versa.

Precautions

1. The fl ow of water in the pipes A and B should be steady.
2. The water should not overfl ow.

3. The pipes A and B must be horizontal.
4. The tubes C and D should be parallel and vertical to each other.

Sources of Error

1. The fl ow of water in the pipes A and B may not be steady.
2. The water is not an ideal fl uid.

3. The pipes may not be perfectly horizontal.

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