Pressure in Liquid

When blood pressure is measured, the cuff of the sphygmomanometer is wrapped round the upper arm and must be held at the level of the heart. Why?

• Blood pressure depends on the level of the blood.

• Blood pressure is normal when the cuff and heart are at the same level.

• Blood is able to flow easily to the wrist.

The pressure of sea water at the bottom of the sea is 1.2 × 108 N m–2.

Determine the depth of the sea.

[Density of sea water = 1020 kg m^–3]

• 1.18×10⁴ m

• 1.18×10⁵ m

• 1.18×10⁶ m

• 1.18×10⁹ m

A submarine has a surface area of 300 m².

The density of sea water is 1050 kg m^–3.

At what depth under the sea, will the additionalpressure on the submarine be 5 × 10⁵ Pa?

[Take g = 10 N kg^–1]

• 47.62 m

• 67.62 m

• 87.62 m

• 57.62 m

The figure below shows a reservoir on a hill. The reservoir supplies water to a water tank on a tall building.

Calculate the water pressure at X.

(Density of water = 1000 kg m^–3)

• 1.4×10⁹ Nm^–2

• 1.4×10² Nm^–2

• 1.4×10⁵ Nm^–2

• 1.4×10⁸ Nm^–2

A coin sinks to a depth of 5 m in a liquid of density 800 kg m^–3. At what depth, in a different liquid of density 600 kg m^–3, will the coin be subjected to the same pressure?

• 6.67 m

• 8.67 m

• 9.67 m

• 5.67 m

The figure shows a pond with two fish P and Q.

What is the correct relation of the water pressures on fish P and fish Q?

• Water pressure on fish Q > Water pressure on fish P.

• Water pressure on fish Q < Water pressure on fish P.

• Water pressure on fish Q = Water pressure on fish P.

The pressure of water exerted on the fishes is P_X, P_Y and P_Z respectively.
Which comparison is correct about the pressure exerted on the fishes?

• P_Z > P_Y > P_X 
• P_Z = P_X < P_Y
• P_Z = P_X > P_Y
• P_Z < P_X < P_Y

Calculate the pressure exerted by the water on the fish.
[Density of water = 1 000 kg m⁻³]

• 5 × 10⁴ Pa
• 5 × 10⁷ Pa
• 5 × 10⁶ Pa
• 5 × 10^-1 Pa

Which of the following graphs shows the correct relationship between water pressure, p and depth, h of the water?

• A
• B
• C
• D

Two identical containers containing liquid M and liquid N with 28 cm height and 20 cm height respectively. Both containers produce the same water spurt.
If the density of liquid M is 2.0 g cm⁻³, find the density of liquid N.

• 0.70 g cm⁻³
• 1.40 g cm⁻³
• 1.43 g cm⁻³
• 2.80 g cm⁻³