This page covers RRB Group D Physics — Everyday Concepts with complete concept notes, 3 graded practice MCQs, key points and exam-specific tips. Free to study.
Core ConceptRead this first — the foundation of the topic
Pressure is a fundamental physics concept that appears regularly in SSC CGL exams. It measures how much force is applied per unit area. Think of it as 'force concentration' - the same force spread over a smaller area creates higher pressure. Core Concept: Pressure = Force ÷ 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.
Key RulesCore rules you must know cold
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.
Formula BlockMemorise — at least one formula appears in every paper
Pressure (P) = Force (F) ÷ Area (A)
Fluid Pressure = Density × g × Height
Atmospheric Pressure = 1.013 × 10^5 Pa = 760 mm Hg
Units: Pascal (Pa), N/m², Bar, Atmosphere, mm Hg
Exam PatternsWhat examiners ask — 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.
ShortcutsUse these to save 30–60 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 × Gravity × Height.
Worked ExampleSolve this step-by-step before moving on
1
Step 1
Identify given values - Force = 200 N, Area = 4 m²
2
Step 2
Apply formula - Pressure = Force ÷ Area
3
Step 3
Substitute values - Pressure = 200 ÷ 4
4
Step 4
Calculate - Pressure = 50 N/m² or 50 Pa
Another Example: If the same 200 N force acts on 2 m² area instead:
Pressure = 200 ÷ 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.
Exam TrapsCommon mistakes students make — avoid these
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.
Key Points to Remember
Pressure = Force ÷ Area - fundamental formula for all pressure calculations
Atmospheric pressure at sea level = 1.013 × 10^5 Pa = 760 mm Hg
Liquid pressure = Density × g × Height, independent of container shape
Pascal's Law: Pressure applied to confined fluid transmits equally in all directions
High pressure created by small area (needle, knife) for cutting applications
Pressure decreases with altitude - 1% decrease per 80m height gain
Barometer measures atmospheric pressure using mercury column height
Hydraulic systems multiply force using pressure and area relationship
Exam-Specific Tips
Standard atmospheric pressure = 1.013 × 10^5 Pascal = 1.013 Bar
Mercury barometer reading at sea level = 760 mm Hg = 76 cm Hg
Pressure unit Pascal named after French scientist Blaise Pascal
1 Bar = 10^5 Pascal = 0.987 atmosphere approximately
Density of mercury = 13,600 kg/m³ used in barometer calculations
Blood pressure measured in mm Hg using sphygmomanometer
Pressure at 10m underwater depth = 2 atmospheric pressure
Hydraulic jack multiplies force based on area ratio principle
Practice MCQs
Physics — Everyday Concepts — Practice Questions
3graded MCQs · easy to hard · full solution & trap analysis
Which of the following is the SI unit of electric current?
Practice 2medium
A ball is thrown vertically upward with an initial velocity of 20 m/s. Assuming g = 10 m/s², what is the maximum height reached by the ball above the point of projection?
Practice 3hard
A person standing on the ground observes that the angle of elevation to the top of a building is 30°. When the person moves 20 meters closer to the building along the same line, the angle of elevation becomes 60°. What is the height of the building?
60-Second Revision — Physics — Everyday Concepts
Formula: Pressure = Force ÷ Area, units Pascal or N/m²
Remember: 1 atm = 1.013 × 10^5 Pa = 760 mm Hg
Liquid pressure depends only on depth, not container shape or volume
Pascal's Law: Pressure transmits equally in all directions in fluids
Applications: Hydraulic brakes, barometers, syringes all use pressure principles
Trap: Don't confuse force with pressure - pressure is force per unit area
Quick conversion: 1 Bar = 10^5 Pa (add/remove 5 zeros)