Pressure & Fluid Thrust — Homi Bhabha Class 9 Physics MCQs with Solutions
Free Homi Bhabha Class 9 Physics Pressure & Fluid Thrust MCQs with step-by-step solutions (10 questions). Part of Gravitation & Pressure. Practise online on Prepizo — no login needed.
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Questions with solutions
Q1 — Pressure & Fluid Thrust · medium · numerical
A force of 200 N acts normally on a surface of area 0.5 m². The pressure exerted is:
A. 100 Pa
B. 400 Pa ✓ Correct
C. 200.5 Pa
D. 40 Pa
Solution: Pressure $= \dfrac{F}{A} = \dfrac{200}{0.5} = 400$ Pa.
Q2 — Pressure & Fluid Thrust · medium · theory
A camel walks easily on soft sand because its broad feet:
A. increase the area and so reduce the pressure on the sand ✓ Correct
B. increase the force on the sand
C. decrease the area and increase pressure
D. reduce its weight
Solution: A larger contact area lowers the pressure ($P = F/A$), so the camel does not sink.
Q3 — Pressure & Fluid Thrust · medium · theory
A sharp knife cuts more easily than a blunt one because a sharp edge:
A. applies a larger force
B. has a larger area and lower pressure
C. reduces the pressure
D. has a smaller area and so produces greater pressure ✓ Correct
Solution: The small edge area concentrates the force into a high pressure, cutting more easily.
Q4 — Pressure & Fluid Thrust · hard · numerical
The same force is applied first over an area of 2 m² and then over 0.5 m². The pressure in the second case compared to the first is:
A. 4 times greater ✓ Correct
B. the same
C. 2 times greater
D. 4 times smaller
Solution: For a fixed force $P \propto \dfrac{1}{A}$; reducing area from 2 to 0.5 m² (a factor of 4) makes the pressure 4 times greater.
Q5 — Pressure & Fluid Thrust · medium · theory
The pressure exerted by a liquid at rest:
A. decreases with depth
B. is the same at all depths
C. is zero at the bottom
D. increases with depth ✓ Correct
Solution: Liquid pressure $= h\rho g$ increases with depth h.
Q6 — Pressure & Fluid Thrust · hard · numerical
The pressure due to a column of water 10 m deep (density $1000$ kg/m³, $g = 10$ m/s²) is:
A. 100000 Pa ✓ Correct
B. 110000 Pa
C. 1000 Pa
D. 10000 Pa
Solution: Pressure $= h\rho g = 10 \times 1000 \times 10 = 100000$ Pa.
Q7 — Pressure & Fluid Thrust · easy · theory
Pressure exerted on a surface is defined as:
A. mass per unit volume
B. force per unit length
C. thrust (force) acting per unit area ✓ Correct
D. force multiplied by area
Solution: Pressure = thrust (the force acting perpendicular to a surface) divided by the area over which it acts, P = F/A.
Q8 — Pressure & Fluid Thrust · easy · numerical
A force of 200 N acts perpendicularly on a surface of area 4 m². The pressure exerted is:
A. 204 Pa
B. 50 Pa ✓ Correct
C. 0.02 Pa
D. 800 Pa
Solution: P = F/A = 200/4 = 50 pascal (1 Pa = 1 N/m²).
Q9 — Pressure & Fluid Thrust · medium · theory
A sharp knife cuts an object more easily than a blunt one because:
A. a sharp knife applies more force
B. a sharp knife has less friction
C. its sharp edge has a very small area, giving a large pressure ✓ Correct
D. a sharp knife is heavier
Solution: For the same force, a smaller contact area gives a larger pressure (P = F/A). A sharp edge has a very small area, so it presses harder and cuts easily.
Q10 — Pressure & Fluid Thrust · hard · numerical
A brick of dimensions 20 cm × 10 cm × 5 cm weighs 15 N. The maximum pressure it can exert while resting on a table is:
A. 1500 Pa
B. 3000 Pa ✓ Correct
C. 300 Pa
D. 750 Pa
Solution: Maximum pressure comes from the smallest face, 10 cm × 5 cm = 50 cm² = 0.005 m². P = 15/0.005 = 3000 Pa.