This page covers SSC CHSL Physics โ Everyday Concepts with complete concept notes, 28 graded practice MCQs, key points and exam-specific tips. Free to study.
Pressure = Force รท Area. When you press a drawing pin into a board, the sharp point creates high pressure because the same force is concentrated on a tiny area. This is why pins pierce easily but your finger pressing with the same force cannot
๐กKey Properties
Pressure is directly proportional to force and inversely proportional to area. Double the force, double the pressure. Double the area, halve the pressure. Pressure acts in all directions in fluids (Pascal's Law).
At any point in a stationary fluid, pressure is the same in all directions.
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Formula Block
Memorise โ at least one formula appears in every paper
Pressure (P) = Force (F) รท Area (A)
Fluid Pressure = Density ร g ร Height
Atmospheric Pressure = 1.013 ร 10^5 Pa = 760 mm Hg
Units: Pascal (Pa), N/mยฒ, Bar, Atmosphere, mm Hg
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Exam Patterns
What examiners ask โ read before attempting PYQs
SSC asks about atmospheric pressure values, pressure applications (hydraulic systems, barometers), and calculation problems. Questions often involve pressure differences at heights, pressure in liquids, and practical applications like syringes, pumps.
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Shortcuts
Use these to save 30โ60 seconds per question
Remember 'FAPA' - Force and Area are in Pressure Always. Increase Force = Increase Pressure. Increase Area = Decrease Pressure.
For fluid pressure, remember 'DGH' - Density ร Gravity ร Height.
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Worked Example
Solve this step-by-step before moving on
1
Step 1
Identify given values - Force = 200 N, Area = 4 mยฒ
2
Step 2
Apply formula - Pressure = Force รท Area
3
Step 3
Substitute values - Pressure = 200 รท 4
4
Step 4
Calculate - Pressure = 50 N/mยฒ or 50 Pa
Another Example: If the same 200 N force acts on 2 mยฒ area instead:
Pressure = 200 รท 2 = 100 Pa
Notice: Half the area means double the pressure.
Shortcut for Unit Conversion: 1 Bar = 10^5 Pa. For quick conversion, Bar to Pa - add 5 zeros. Pa to Bar - remove 5 zeros.
Common Mistakes: Students often confuse force with pressure. Remember - force is push or pull, pressure is force per unit area. Another mistake is forgetting that liquid pressure depends on depth (height of liquid column), not the total volume. A thin tube and wide tank at same depth have equal pressure at bottom.
Practical Applications tested: Hydraulic brakes work on Pascal's law. Barometers measure atmospheric pressure. Syringes work due to pressure difference. Mountain climbers face low pressure at heights. Deep sea divers face high pressure underwater.
Test Physics โ Everyday Concepts under exam conditions