What is Pressure = ?
Pressure : āĻāĻžāĻĒ
Pressure is the force acting per unit area. āĻāĻžāĻĒ āĻšā§āĻā§ āĻāĻāĻ āĻā§āώā§āϤā§ā§°āĻĢāϞāϤ āĻĒā§ā§°āϝāĻŧā§āĻ āĻā§°āĻž āĻŦāϞāĨ¤
Formula / āϏā§āϤā§ā§° : P = F/A
Where / āϝ’āϤ : = Pressure (āĻāĻžāĻĒ), = Force (āĻŦāϞ), = Area (āĻā§āώā§āϤā§ā§°āĻĢāϞ)
SI Unit / SI āĻāĻāĻ : Pascal (Pa) - āĻĒāĻžāϏā§āĻāĻžāϞ (Pa)
Important Point / āĻā§ā§°ā§āϤā§āĻŦāĻĒā§āϰā§āĻŖ āĻāĻĨāĻž
- Greater force produces greater pressure. (āĻ āϧāĻŋāĻ āĻŦāϞ⧠āĻ āϧāĻŋāĻ āĻāĻžāĻĒ āĻā§āĻĒāύā§āύ āĻā§°ā§āĨ¤)
- Smaller area produces greater pressure. (āĻāĻŽ āĻā§āώā§āϤā§ā§°āĻĢāϞāϤ āĻ āϧāĻŋāĻ āĻāĻžāĻĒ āϏā§āώā§āĻāĻŋ āĻšāϝāĻŧāĨ¤)
Examples / āĻāĻĻāĻžāĻšā§°āĻŖ
- Sharp knives cut easily because pressure is high on a small area. (āϧāĻžāϰāĻžāϞ⧠āĻā§ā§°ā§āϝāĻŧā§ āϏāĻšāĻā§ āĻāĻžāĻā§ āĻāĻžā§°āĻŖ āĻāĻŽ āĻā§āώā§āϤā§ā§°āĻĢāϞāϤ āĻ āϧāĻŋāĻ āĻāĻžāĻĒ āĻā§āĻĒāύā§āύ āĻšāϝāĻŧāĨ¤)
- High heels exert more pressure on the ground. (High heel-āĻ āĻŽāĻžāĻāĻŋāϤ āĻ āϧāĻŋāĻ āĻāĻžāĻĒ āĻĒā§ā§°āϝāĻŧā§āĻ āĻā§°ā§āĨ¤)
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Pressure – 2 Marks Questions with Answers : āĻāĻžāĻĒ – ⧍ āύāĻŽā§āĻŦā§°ā§° āĻĒā§ā§°āĻļā§āύā§āϤā§āϤ⧰
1. What is pressure ? āĻāĻžāĻĒ āĻāĻŋ ?
Ans: Pressure is the force acting per unit area. āĻāϤā§āϤ⧰: āĻāĻžāĻĒ āĻšā§āĻā§ āĻāĻāĻ āĻā§āώā§āϤā§ā§°āĻĢāϞāϤ āĻĒā§ā§°āϝāĻŧā§āĻ āĻā§°āĻž āĻŦāϞāĨ¤
2. Write the formula of pressure. āĻāĻžāĻĒā§° āϏā§āϤā§ā§° āϞāĻŋāĻāĻžāĨ¤
Ans: P = F/A, Pressure is equal to force divided by area.
āĻāϤā§āϤ⧰: āĻāĻžāĻĒ = āĻŦāϞ ÷ āĻā§āώā§āϤā§ā§°āĻĢāϞāĨ¤
3. What is the SI unit of pressure ? āĻāĻžāĻĒā§° SI āĻāĻāĻ āĻāĻŋ ?
Ans: The SI unit of pressure is Pascal (Pa). āĻāϤā§āϤ⧰: āĻāĻžāĻĒā§° SI āĻāĻāĻ āĻšā§āĻā§ Pascal (Pa)āĨ¤
4. How can pressure be increased ? āĻāĻžāĻĒ āĻā§āύā§āĻā§ āĻŦā§āĻĻā§āϧāĻŋ āĻā§°āĻŋāĻŦ āĻĒāĻžā§°āĻŋ ?
Ans: Pressure can be increased by increasing force or decreasing area. āĻāϤā§āϤ⧰: āĻŦāϞ āĻŦā§āĻĻā§āϧāĻŋ āĻā§°āĻŋ āĻŦāĻž āĻā§āώā§āϤā§ā§°āĻĢāϞ āĻāĻŽāĻžāĻ āĻāĻžāĻĒ āĻŦā§āĻĻā§āϧāĻŋ āĻā§°āĻŋāĻŦ āĻĒāĻžā§°āĻŋāĨ¤
5. Why do sharp knives cut easily ? āϧāĻžāϰāĻžāϞ⧠āĻā§ā§°ā§āϝāĻŧā§ āϏāĻšāĻā§ āĻāĻŋāϝāĻŧ āĻāĻžāĻā§ ?
Ans: Sharp knives have smaller area, so they produce greater pressure. āĻāϤā§āϤ⧰: āϧāĻžā§°āĻžāϞ⧠āĻā§ā§°ā§ā§° āĻā§āώā§āϤā§ā§°āĻĢāϞ āĻāĻŽ āĻšāϝāĻŧ, āϏā§āϝāĻŧā§āĻšā§ āĻ āϧāĻŋāĻ āĻāĻžāĻĒ āĻā§āĻĒāύā§āύ āĻā§°ā§āĨ¤
Pressure – 5 Marks Questions with Answers : āĻāĻžāĻĒ – ā§Ģ āύāĻŽā§āĻŦā§°ā§° āĻĒā§ā§°āĻļā§āύā§āϤā§āϤ⧰
1. Define pressure and write its formula and SI unit. āĻāĻžāĻĒā§° āϏāĻāĻā§āĻāĻž āĻĻāĻŋāϝāĻŧāĻž āĻā§°ā§ āĻāϝāĻŧāĻžā§° āϏā§āϤā§ā§° āĻā§°ā§ SI āĻāĻāĻ āϞāĻŋāĻāĻžāĨ¤
Ans: Pressure is the force acting per unit area.
Formula: P = F/ASI unit: Pascal (Pa)
āĻāϤā§āϤ⧰: āĻāĻžāĻĒ āĻšā§āĻā§ āĻāĻāĻ āĻā§āώā§āϤā§ā§°āĻĢāϞāϤ āĻĒā§ā§°āϝāĻŧā§āĻ āĻā§°āĻž āĻŦāϞāĨ¤ SI āĻāĻāĻ: Pascal (Pa)
2. Explain how area affects pressure. āĻā§āώā§āϤā§ā§°āĻĢāϞ⧠āĻāĻžāĻĒāĻ āĻā§āύā§āĻā§ āĻĒā§ā§°āĻāĻžā§ąāĻŋāϤ āĻā§°ā§ āĻŦā§āϝāĻžāĻā§āϝāĻž āĻā§°āĻžāĨ¤
Ans: Pressure is inversely proportional to area. If the area decreases, pressure increases. If the area increases, pressure decreases. āĻāϤā§āϤ⧰: āĻāĻžāĻĒ āĻā§āώā§āϤā§ā§°āĻĢāϞ⧰ āĻŦāĻŋāĻĒā§°ā§āϤ āϏāĻŽāĻžāύā§āĻĒāĻžāϤāĻŋāĻāĨ¤ āĻā§āώā§āϤā§ā§°āĻĢāϞ āĻāĻŽāĻŋāϞ⧠āĻāĻžāĻĒ āĻŦā§āĻĻā§āϧāĻŋ āĻĒāĻžāϝāĻŧ āĻā§°ā§ āĻā§āώā§āϤā§ā§°āĻĢāϞ āĻŦā§āĻĻā§āϧāĻŋ āĻĒāĻžāϞ⧠āĻāĻžāĻĒ āĻāĻŽā§āĨ¤
3. Why do camels have broad feet ? āĻāĻā§° āĻā§°āĻŋ āĻŦāĻšāϞ āĻāĻŋāϝāĻŧ āĻšāϝāĻŧ ?
Ans: Camels have broad feet to reduce pressure on sand. Larger area reduces pressure and prevents sinking. āĻāϤā§āϤ⧰: āĻāĻā§° āĻā§°āĻŋ āĻŦāĻšāϞ āĻšāϝāĻŧ āϝāĻžāϤ⧠āĻŦāĻžāϞāĻŋāϤ āĻāĻžāĻĒ āĻāĻŽ āĻšāϝāĻŧāĨ¤ āĻ āϧāĻŋāĻ āĻā§āώā§āϤā§ā§°āĻĢāϞ⧠āĻāĻžāĻĒ āĻāĻŽāĻžāϝāĻŧ āĻā§°ā§ āĻĄā§āĻŦāĻŋ āϝā§ā§ąāĻžāϤ āĻŦāĻžāϧāĻž āĻĻāĻŋāϝāĻŧā§āĨ¤
4. Explain why nails have pointed ends. āĻĒā§ā§°ā§āĻā§° āĻāĻāĻāĻžāĻ āϤā§āĻā§āώā§āĻŖ āĻāĻŋāϝāĻŧ āĻšāϝāĻŧ āĻŦā§āϝāĻžāĻā§āϝāĻž āĻā§°āĻžāĨ¤
Ans: Pointed ends have very small area, so greater pressure is produced, making it easier to penetrate objects. āĻāϤā§āϤ⧰: āϤā§āĻā§āώā§āĻŖ āĻāĻāĻāĻžāĻāϤ āĻā§āώā§āϤā§ā§°āĻĢāϞ āĻāĻŽ āĻšāϝāĻŧ, āϏā§āϝāĻŧā§āĻšā§ āĻ āϧāĻŋāĻ āĻāĻžāĻĒ āĻā§āĻĒāύā§āύ āĻšāϝāĻŧ āĻā§°ā§ āĻŦāϏā§āϤā§āϤ āϏāĻšāĻā§ āϏā§āĻŽāĻžāϝāĻŧāĨ¤
5. Mention two everyday applications of pressure. āĻāĻžāĻĒā§° āĻĻā§āύāύā§āĻĻāĻŋāύ āĻā§ā§ąāύ⧰ āĻĻā§āĻāĻž āĻŦā§āĻ¯ā§ąāĻšāĻžā§° āĻāϞā§āϞā§āĻ āĻā§°āĻžāĨ¤
Ans: i. Sharp knives for cutting (āĻāĻžāĻāĻŋāĻŦāϞ⧠āϧāĻžāϰāĻžāϞ⧠āĻā§ā§°ā§), ii. Syringes for injecting medicine (āĻāώāϧ āĻĻāĻŋāĻŦāϞ⧠syringe)