Pressure and Depth
3 marks · NormalA diver is swimming at a depth of m below the surface of freshwater. The density of freshwater is . The gravitational field strength is .
Calculate the pressure difference between the diver and the water surface.
State the relationship used to calculate the pressure difference in this situation.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
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(a) 78400 Pa · must show working shown, h, ρ, g substitution
(b) p = h × ρ × g
Common mistakes: using density in g/cm³; omitting units; using atmospheric pressure
Show mark scheme and worked solution
Marking points
M1 (a) · 1 mark · Substitutes correct values: h=8.0, ρ=1000, g=9.8, or clear rearrangement.
A1 (a) · 1 mark · Correct evaluation: 78400 Pa (accept values in range for g=10). (follow-through)
B1 (b) · 1 mark · Correctly states p = h × ρ × g or equivalent.
Worked solution
The pressure difference is calculated using the formula .
Relationship used: