Why Does Steam Burn More Than Boiling Water ? : āĻāĻžāĻĒ (Steam) āĻ āĻāĻŋāϝāĻŧ āĻāϤāϞāĻž āĻĒāĻžāύā§āϤāĻā§ āĻŦā§āĻāĻŋ āĻā§āĻŦāϞāĻžāĻ ?
- Steam is water in gas form. āĻāĻžāĻĒ āĻšā§āĻā§ āĻĒāĻžāύā§ā§° āĻā§āĻā§āϝāĻŧ āĻ ā§ąāϏā§āĻĨāĻžāĨ¤
- Steam contains extra heat energy. āĻāĻžāĻĒāϤ āĻ āϤāĻŋā§°āĻŋāĻā§āϤ āϤāĻžāĻĒ āĻļāĻā§āϤāĻŋ āĻĨāĻžāĻā§āĨ¤
- When steam touches skin, it condenses. āĻāĻžāĻĒā§ āĻāĻžāϞ āϏā§āĻĒā§°ā§āĻļ āĻā§°āĻŋāϞ⧠āĻ āĻāύā§āĻā§ąāύ (Condensation) āĻšāϝāĻŧāĨ¤
- During condensation, steam releases heat.āĻāύā§āĻā§ąāύ⧰ āϏāĻŽāϝāĻŧāϤ āĻāĻžāĻĒā§ āϤāĻžāĻĒ āĻŽā§āĻā§āϤ āĻā§°ā§āĨ¤
- This extra heat causes severe burns. āĻāĻ āĻ āϤāĻŋā§°āĻŋāĻā§āϤ āϤāĻžāĻĒā§āĻ āĻāĻŽā§āĻā§ā§° āĻā§āĻŦāϞāĻž āϏā§āώā§āĻāĻŋ āĻā§°ā§āĨ¤
- Boiling water does not release this extra energy. āĻāϤāϞāĻž āĻĒāĻžāύā§āϝāĻŧā§ āĻāĻ āĻ āϤāĻŋā§°āĻŋāĻā§āϤ āϤāĻžāĻĒ āĻŽā§āĻā§āϤ āύāĻā§°ā§āĨ¤
Important Terms - āĻā§ā§°ā§āϤā§āĻŦāĻĒā§ā§°ā§āĻŖ āĻļāĻŦā§āĻĻ
- Condensation – Heat Release : āĻāύā§āĻā§ąāύ – āϤāĻžāĻĒ āĻŽā§āĻā§āϤāĻŋ
- Steam – Gas form of water : āĻāĻžāĻĒ – āĻĒāĻžāύā§ā§° āĻā§āĻā§āϝāĻŧ āĻ ā§ąāϏā§āĻĨāĻž
- Boiling Water – Liquid form : āĻāϤāϞāĻž āĻĒāĻžāύ⧠– āĻĒāĻžāύā§ā§° āϤāϰāϞ āĻ ā§ąāϏā§āĻĨāĻž
Key Point : āĻŽā§āĻā§āϝ āĻāĻĨāĻž
Steam burns more because it releases extra heat when it condenses. āĻāĻžāĻĒā§ āĻāύā§āĻā§ąāύ āĻšā§ā§ąāĻžā§° āϏāĻŽāϝāĻŧāϤ āĻ āϤāĻŋā§°āĻŋāĻā§āϤ āϤāĻžāĻĒ āĻŽā§āĻā§āϤ āĻā§°ā§, āϏā§āϝāĻŧā§āĻšā§ āĻ āĻāϤāϞāĻž āĻĒāĻžāύā§āϤāĻā§ āĻŦā§āĻāĻŋ āĻā§āĻŦāϞāĻžāĻāĨ¤
MCQ Set
Q1. Why does steam burn more than boiling water ? : āĻāĻžāĻĒā§ āĻāϤāϞāĻž āĻĒāĻžāύā§āϤāĻā§ āĻāĻŋāϝāĻŧ āĻŦā§āĻāĻŋ āĻā§āĻŦāϞāĻžāĻ ?
(a) Steam is hotter : āĻāĻžāĻĒ āĻŦā§āĻāĻŋ āĻā§°āĻŽ
(b) Steam releases extra heat on condensation : āĻāĻžāĻĒā§ āĻāύā§āĻā§ąāύāϤ āĻ
āϤāĻŋā§°āĻŋāĻā§āϤ āϤāĻžāĻĒ āĻŽā§āĻā§āϤ āĻā§°ā§
(c) Steam is heavier : āĻāĻžāĻĒ āĻāĻžā§°ā§
(d) Steam sticks to skin : āĻāĻžāĻĒ āĻāĻžāϞāϤ āϞāĻžāĻāĻŋ āĻĨāĻžāĻā§
Ans: (b)
Explanation: Steam releases extra heat when it condenses on skin. āĻŦā§āϝāĻžāĻā§āϝāĻž: āĻāĻžāĻĒā§ āĻāύā§āĻā§ąāύ⧰ āϏāĻŽāϝāĻŧāϤ āĻ āϤāĻŋā§°āĻŋāĻā§āϤ āϤāĻžāĻĒ āĻŽā§āĻā§āϤ āĻā§°ā§āĨ¤
Q2. Steam is water in which form ? : āĻāĻžāĻĒ āĻĒāĻžāύā§ā§° āĻā§āύ āĻ ā§ąāϏā§āĻĨāĻž ?
(a) Solid : āĻāĻ āĻŋāύ (b) Liquid : āϤāϰāϞ (c) Gas : āĻā§āĻ (d) Plasma : āĻĒā§āϞāĻžāĻāĻŽāĻž
Ans: (c)
Explanation: Steam is gaseous water. āĻŦā§āϝāĻžāĻā§āϝāĻž: āĻāĻžāĻĒ āĻšā§āĻā§ āĻĒāĻžāύā§ā§° āĻā§āĻā§āϝāĻŧ āĻ ā§ąāϏā§āĻĨāĻžāĨ¤
Q3. Boiling water is at what temperature ? : āĻāϤāϞāĻž āĻĒāĻžāύā§ā§° āϤāĻžāĻĒāĻŽāĻžāύ āĻāĻŋāĻŽāĻžāύ ?
(a) 50°C : ā§Ģā§Ļ°āϏ⧠(b) 80°C : ā§Žā§Ļ°āϏ⧠(c) 100°C : ā§§ā§Ļā§Ļ°āϏ⧠(d) 120°C : ⧧⧍ā§Ļ°āϏā§
Ans: (c)
Explanation: Water boils at 100°C. āĻŦā§āϝāĻžāĻā§āϝāĻž: āĻĒāĻžāύ⧠⧧ā§Ļā§Ļ°āϏ⧠āϤ āĻāϤāϞā§āĨ¤
Q4. When steam touches skin, it - : āĻāĻžāĻĒā§ āĻāĻžāϞ āϏā§āĻĒā§°ā§āĻļ āĻā§°āĻŋāϞ⧠-
(a) Evaporates : āĻŦāĻžāώā§āĻĒā§āĻā§ąāύ āĻšāϝāĻŧ (b) Condenses : āĻāύā§āĻā§ąāύ āĻšāϝāĻŧ (c) Freezes : āĻāĻŽā§ (d) Expands : āĻĢā§āϞāĻžāĻ āĻāĻ ā§
Ans: (b)
Explanation: Steam condenses into water. āĻŦā§āϝāĻžāĻā§āϝāĻž: āĻāĻžāĻĒ āĻĒāĻžāύ⧠āĻšā§ āĻāύā§āĻā§ąāύ āĻšāϝāĻŧāĨ¤
Q5. Condensation means - : āĻāύā§āĻā§ąāύ āĻŽāĻžāύ⧠-
(a) Liquid → Gas : āϤāϰāϞ → āĻā§āĻ (b) Solid → Liquid : āĻāĻ āĻŋāύ → āϤāϰāϞ
(c) Gas → Liquid : āĻā§āĻ → āϤāϰāϞ (d) Solid → Gas : āĻāĻ āĻŋāύ → āĻā§āĻ
Ans: (c)
Explanation: Gas changes into liquid. āĻŦā§āϝāĻžāĻā§āϝāĻž: āĻā§āĻ āϤāϰāϞāϞ⧠āĻĒā§°āĻŋāĻŖāϤ āĻšāϝāĻŧāĨ¤
Q6. During condensation, heat is - : āĻāύā§āĻā§ąāύ⧰ āϏāĻŽāϝāĻŧāϤ āϤāĻžāĻĒ -
(a) Absorbed : āĻļā§āώāĻŖ āĻšāϝāĻŧ (b) Released : āĻŽā§āĻā§āϤ āĻšāϝāĻŧ (c) Destroyed : āύāώā§āĻ āĻšāϝāĻŧ (d) Frozen : āĻāĻŽā§
Ans: (b)
Explanation: Heat is released during condensation. āĻŦā§āϝāĻžāĻā§āϝāĻž: āĻāύā§āĻā§ąāύāϤ āϤāĻžāĻĒ āĻŽā§āĻā§āϤ āĻšāϝāĻŧāĨ¤
Q7. The extra heat released by steam is called - : āĻāĻžāĻĒā§ āĻŽā§āĻā§āϤ āĻā§°āĻž āĻ āϤāĻŋā§°āĻŋāĻā§āϤ āϤāĻžāĻĒāĻ āĻā§ā§ąāĻž āĻšāϝāĻŧ -
(a) Kinetic heat : āĻāϤāĻŋāĻļā§āϞ āϤāĻžāĻĒ (b) Latent heat : āĻā§āĻĒāύ āϤāĻžāĻĒ
(c) Solar heat : āϏā§ā§° āϤāĻžāĻĒ (d) Electrical heat : āĻŦā§āĻĻā§āϝā§āϤāĻŋāĻ āϤāĻžāĻĒ
Ans: (b)
Explanation: Steam has latent heat. āĻŦā§āϝāĻžāĻā§āϝāĻž: āĻāĻžāĻĒāϤ āĻā§āĻĒāύ āϤāĻžāĻĒ āĻĨāĻžāĻā§āĨ¤
Q8. Steam causes severe burns because - : āĻāĻžāĻĒā§ āĻāĻŽā§āĻā§ā§° āĻā§āĻŦāϞāĻž āĻā§°ā§ āĻāĻžā§°āĻŖ -
(a) It is dry : āĻ āĻļā§āĻāĻžāύ (b) It is fast : āĻ āĻĻā§ā§°ā§āϤ
(c) It releases latent heat : āĻ āĻā§āĻĒāύ āϤāĻžāĻĒ āĻŽā§āĻā§āϤ āĻā§°ā§ (d) It cools skin : āĻ āĻāĻžāϞ āĻ āĻžāĻŖā§āĻĄāĻž āĻā§°ā§
Ans: (c)
Explanation: Latent heat increases burning effect. āĻŦā§āϝāĻžāĻā§āϝāĻž: āĻā§āĻĒāύ āϤāĻžāĻĒā§ āĻā§āĻŦāϞāĻž āĻŦā§āĻāĻŋ āĻā§°ā§āĨ¤
Q9. Which causes more burn at 100°C ? : ā§§ā§Ļā§Ļ°āϏ⧠āϤ āĻā§āύ⧠āĻŦā§āĻāĻŋ āĻā§āĻŦāϞāĻžāĻ ?
(a) Ice : āĻŦā§°āĻĢ (b) Cold water : āĻ āĻžāĻŖā§āĻĄāĻž āĻĒāĻžāύ⧠(c) Boiling water : āĻāϤāϞāĻž āĻĒāĻžāύ⧠(d) Steam : āĻāĻžāĻĒ
Ans: (d)
Explanation: Steam releases extra heat. āĻŦā§āϝāĻžāĻā§āϝāĻž: āĻāĻžāĻĒā§ āĻ āϤāĻŋā§°āĻŋāĻā§āϤ āϤāĻžāĻĒ āĻŽā§āĻā§āϤ āĻā§°ā§āĨ¤
Q10. Boiling water does NOT- : āĻāϤāϞāĻž āĻĒāĻžāύā§āϝāĻŧā§ āĻāĻŋ āύāĻā§°ā§ ?
(a) Burn skin : āĻāĻžāϞ āĻā§āĻŦāϞāĻžāĻ (b) Contain heat : āϤāĻžāĻĒ āĻĨāĻžāĻā§
(c) Release latent heat : āĻā§āĻĒāύ āϤāĻžāĻĒ āĻŽā§āĻā§āϤ āĻā§°ā§ (d) Cause pain : āĻŦāĻŋāώ āĻā§°ā§
Ans: (c)
Explanation: No condensation, no latent heat release. āĻŦā§āϝāĻžāĻā§āϝāĻž: āĻāύā§āĻā§ąāύ āύā§āĻšā§ā§ąāĻžāϤ āĻā§āĻĒāύ āϤāĻžāĻĒ āύāĻžāĻĨāĻžāĻā§āĨ¤
Q11. Steam first changes into - : āĻāĻžāĻĒ āĻĒā§ā§°āĻĨāĻŽā§ āĻāĻŋ āĻšā§ āϝāĻžāϝāĻŧ ?
(a) Ice : āĻŦā§°āĻĢ (b) Water : āĻĒāĻžāύ⧠(c) Air : āĻŦāĻžāϝāĻŧā§ (d) Smoke: āϧā§āĻā§ąāĻž
Ans: (b)
Explanation: Steam condenses into water. āĻŦā§āϝāĻžāĻā§āϝāĻž: āĻāĻžāĻĒ āĻĒāĻžāύ⧠āĻšāϝāĻŧāĨ¤
Q12. Which has more energy at same temperature ? : āĻāĻā§ āϤāĻžāĻĒāĻŽāĻžāύāϤ āĻā§āύāĻā§ā§° āĻļāĻā§āϤāĻŋ āĻŦā§āĻāĻŋ ?
(a) Ice : āĻŦā§°āĻĢ (b) Cold water : āĻ āĻžāĻŖā§āĻĄāĻž āĻĒāĻžāύ⧠(c) Boiling water : āĻāϤāϞāĻž āĻĒāĻžāύ⧠(d) Steam : āĻāĻžāĻĒ
Ans: (d)
Explanation: Steam has extra latent heat. āĻŦā§āϝāĻžāĻā§āϝāĻž: āĻāĻžāĻĒāϤ āĻā§āĻĒāύ āϤāĻžāĻĒ āĻĨāĻžāĻā§āĨ¤
Q13. Latent heat is heat - : āĻā§āĻĒāύ āϤāĻžāĻĒ āĻŽāĻžāύ⧠-
(a) Seen heat : āĻĻā§āĻāĻž āϤāĻžāĻĒ (b) Used for temperature rise : āϤāĻžāĻĒāĻŽāĻžāύ āĻŦāĻĸāĻŧāĻžāĻŦāϞ⧠āĻŦā§āĻ¯ā§ąāĻšā§āϤ
(c) Released without temperature change : āϤāĻžāĻĒāĻŽāĻžāύ āύāϏāϞāύāĻŋ āĻā§°āĻŋ āĻŽā§āĻā§āϤ āĻšā§ā§ąāĻž (d) Cold energy : āĻ āĻžāĻŖā§āĻĄāĻž āĻļāĻā§āϤāĻŋ
Ans: (c)
Explanation: Latent heat changes state, not temperature. āĻŦā§āϝāĻžāĻā§āϝāĻž: āĻā§āĻĒāύ āϤāĻžāĻĒā§ āĻ ā§ąāϏā§āĻĨāĻž āϏāϞāύāĻŋ āĻā§°ā§āĨ¤
Q14. Steam burn is more dangerous because - : āĻāĻžāĻĒā§° āĻā§āĻŦāϞāĻž āĻ āϧāĻŋāĻ āĻŦāĻŋāĻĒāĻā§āĻāύāĻ āĻāĻžā§°āĻŖ -
(a) Steam is invisible : āĻāĻžāĻĒ āĻĻā§āĻāĻž āύāĻžāϝāĻžāϝāĻŧ (b) Steam sticks longer : āĻāĻžāĻĒ āĻŦā§āĻāĻŋ āϏāĻŽāϝāĻŧ āĻĨāĻžāĻā§
(c) Steam releases more heat : āĻāĻžāĻĒā§ āĻ
āϧāĻŋāĻ āϤāĻžāĻĒ āĻŽā§āĻā§āϤ āĻā§°ā§ (d) Steam is poisonous : āĻāĻžāĻĒ āĻŦāĻŋāώāĻžāĻā§āϤ
Ans: (c)
Explanation: Extra heat damages skin more. āĻŦā§āϝāĻžāĻā§āϝāĻž: āĻ āϧāĻŋāĻ āϤāĻžāĻĒā§ āĻāĻžāϞ āĻŦā§āĻāĻŋ āĻā§āώāϤāĻŋ āĻā§°ā§āĨ¤
Q15. When steam condenses, temperature - : āĻāĻžāĻĒ āĻāύā§āĻā§ąāύ āĻš'āϞ⧠āϤāĻžāĻĒāĻŽāĻžāύ -
(a) Increases : āĻŦāĻĸāĻŧā§ (b) Decreases : āĻāĻŽā§ (c) Remains same : āĻāĻā§ āĻĨāĻžāĻā§ (d) Becomes zero : āĻļā§āύā§āϝ āĻšāϝāĻŧ
Ans: (c)
Explanation: Latent heat is released at same temperature. āĻŦā§āϝāĻžāĻā§āϝāĻž: āĻāĻā§ āϤāĻžāĻĒāĻŽāĻžāύāϤ⧠āĻā§āĻĒāύ āϤāĻžāĻĒ āĻŽā§āĻā§āϤ āĻšāϝāĻŧāĨ¤
Q16. Steam burns are common in - : āĻāĻžāĻĒā§° āĻā§āĻŦāϞāĻž āϏāĻžāϧāĻžā§°āĻŖāϤ⧠āĻšāϝāĻŧ -
(a) Kitchens : ā§°āύā§āϧāύāĻā§° (b) Ice factories : āĻŦā§°āĻĢ āĻāϞ (c) Deserts : āĻŽā§°ā§āĻā§āĻŽāĻŋ (d) Mountains : āĻĒāĻžāĻšāĻžā§°
Ans: (a)
Explanation: Steam is common in cooking. āĻŦā§āϝāĻžāĻā§āϝāĻž: ā§°āύā§āϧāύāϤ āĻāĻžāĻĒ āĻŦā§āĻāĻŋ āĻĨāĻžāĻā§āĨ¤
Q17. Steam is formed when - : āĻāĻžāĻĒ āĻā§āϤāĻŋāϝāĻŧāĻž āϏā§āώā§āĻāĻŋ āĻšāϝāĻŧ ?
(a) Ice melts : āĻŦā§°āĻĢ āĻāϞ⧠(b) Water freezes : āĻĒāĻžāύ⧠āĻāĻŽā§ (c) Water boils : āĻĒāĻžāύ⧠āĻāϤāϞ⧠(d) Water cools : āĻĒāĻžāύ⧠āĻ āĻžāĻŖā§āĻĄāĻž āĻšāϝāĻŧ
Ans: (c)
Explanation: Boiling produces steam. āĻŦā§āϝāĻžāĻā§āϝāĻž: āĻāϤāϞāĻŋāϞ⧠āĻāĻžāĻĒ āϏā§āώā§āĻāĻŋ āĻšāϝāĻŧāĨ¤
Q18. Which change occurs when steam burns skin ? : āĻāĻžāĻĒā§ āĻā§āĻŦāϞāĻžāĻ āĻĻāĻŋāϞ⧠āĻā§āύ āĻĒā§°āĻŋāĻŦā§°ā§āϤāύ āĻāĻā§ ?
(a) Only physical : āĻā§ā§ąāϞ āĻā§āϤ (b) Only chemical : āĻā§ā§ąāϞ ā§°āĻžāϏāĻžāϝāĻŧāύāĻŋāĻ
(c) Both physical and heat transfer : āĻā§āϤ āĻā§°ā§ āϤāĻžāĻĒ āϏā§āĻĨāĻžāύāĻžāύā§āϤ⧰ (d) Nuclear : āύāĻŋāĻāĻā§āϞāĻŋāϝāĻŧāĻžā§°
Ans: (c)
Explanation: Heat transfer with state change. āĻŦā§āϝāĻžāĻā§āϝāĻž: āϤāĻžāĻĒ āϏā§āĻĨāĻžāύāĻžāύā§āϤ⧰ āĻā§°ā§ āĻ
ā§ąāϏā§āĻĨāĻž āϏāϞāύāĻŋāĨ¤
Q19. Steam burn shows importance of - : āĻāĻžāĻĒā§° āĻā§āĻŦāϞāĻžāĻ āĻāĻŋ āĻā§ā§°ā§āϤā§āĻŦ āĻĻā§āĻā§ā§ąāĻžāϝāĻŧ ?
(a) Gravity : āĻŽāĻšāĻžāĻāϰā§āώ (b) Latent heat : āĻā§āĻĒāύ āϤāĻžāĻĒ (c) Reflection : āĻĒā§ā§°āϤāĻŋāĻĢāϞāύ (d) Sound : āĻļāĻŦā§āĻĻ
Ans: (b)
Explanation: Latent heat causes extra burning. āĻŦā§āϝāĻžāĻā§āϝāĻž: āĻā§āĻĒāύ āϤāĻžāĻĒā§ āĻŦā§āĻāĻŋ āĻā§āĻŦāϞāĻž āĻā§°ā§āĨ¤
Q20. Main reason steam burns more is - : āĻāĻžāĻĒā§ āĻŦā§āĻāĻŋ āĻā§āĻŦāϞāĻžā§° āĻŽā§āĻā§āϝ āĻāĻžā§°āĻŖ -
(a) High speed : āĻ
āϧāĻŋāĻ āĻāϤāĻŋ (b) More pressure : āĻ
āϧāĻŋāĻ āĻāĻžāĻĒ
(c) Release of latent heat on condensation : āĻāύā§āĻā§ąāύāϤ āĻā§āĻĒāύ āϤāĻžāĻĒ āĻŽā§āĻā§āϤāĻŋ (d) Colourless nature : ā§°āĻ āύāĻĨāĻāĻž
Ans: (c)
Explanation: Condensation releases extra heat energy. āĻŦā§āϝāĻžāĻā§āϝāĻž: āĻāύā§āĻā§ąāύāϤ āĻ
āϤāĻŋā§°āĻŋāĻā§āϤ āϤāĻžāĻĒ āĻļāĻā§āϤāĻŋ āĻŽā§āĻā§āϤ āĻšāϝāĻŧāĨ¤
Key Point | āĻŽā§āĻā§āϝ āĻāĻĨāĻž
Steam burns more because it releases extra heat when it condenses on skin. āĻāĻžāĻĒā§ āĻāĻžāϞāϤ āĻāύā§āĻā§ąāύ āĻšā§ā§ąāĻžā§° āϏāĻŽāϝāĻŧāϤ āĻā§āĻĒāύ āϤāĻžāĻĒ āĻŽā§āĻā§āϤ āĻā§°ā§, āϏā§āϝāĻŧā§āĻšā§ āĻ āĻāϤāϞāĻž āĻĒāĻžāύā§āϤāĻā§ āĻŦā§āĻāĻŋ āĻā§āĻŦāϞāĻžāĻāĨ¤