CALORIMETRY
QUESTIONS FOR SHORT ANSWER
QUESTIONS FOR SHORT ANSWER
1. Is heat a conserved quantity?
Answer: Since heat is a form of energy, it is conserved. If different bodies at different temperatures are put in closed surroundings in contact, heat is exchanged among them till all are at the same temperature. But the total amount of heat before contact is the same as at the final temperature.
2. The calorie is defined as 1 cal = 4.186 joule. Why not as 1 cal = 4 J to make the conversions easy?
Answer: Both one calorie of heat and 4.186 joules of mechanical work raise the temperature of 1 g of water by 1°C. Therefore 1 cal is defined equal to 4.186 Joules, it is not arbitrary.
3. A calorimeter is kept in a wooden box to insulate it thermally from the surroundings. Why is it necessary?
Answer: The principle of calorimetry states that the total heat given by the hot objects equals the total heat received by the cold objects. Therefore the calorimeter is kept in a wooden box to insulate it thermally from the surroundings so that the heat of hot bodies is not lost to the surroundings.
4. In a calorimeter, the heat given by the hot object is assumed to be equal to the heat taken by the cold object. Does it mean that the heat of the two objects taken together remains constant?
Answer: Yes, heat is a form of energy so it is conserved. The heat of the two objects taken together remains constant.
5. In Renault's apparatus for measuring the specific heat capacity of a solid, there is an inlet and an outlet in the steam chamber. The inlet is near the top and the outlet is near the bottom. Why is it better than the opposite choice where the inlet is near the bottom and the outlet is near the top?
Answer: The steam when enters the chamber it starts losing heat and goes down. That is why the inlet of steam is kept on the upper side to make the solid evenly hot. The opposite arrangement is not suitable because it will not heat the solid correctly.
6. When a solid melt or a liquid boils, the temperature does not increase even when the heat is supplied. Where does the energy go?
Answer: The heat supplied is used to make the bond between the molecules weaker so that the molecules move freely than the solid-state in a melting solid and than the liquid state in a boiling liquid. It is the reason the temperature does not increase even when the heat is supplied.
7. What is the specific heat capacity of (a) melting ice (b) boiling water?
Answer: The specific heat capacity is defined as the amount of heat needed to raise the temperature of the unit mass of a substance by 1°C or 1K. Since the temperature of melting ice or the boiling water does not increase whatever amount of heat is supplied, both of them will have theoretically infinite specific heat capacity.
8. A person's skin is more severely burnt when putting in contact with 1 g of steam at 100°C than when putting in contact with 1 g of water at 100°C. Explain.
Answer: Due to the latent heat of vaporization 1 g of steam at 100°C has greater energy than the 1 g of water at 100°C. Therefore a person's skin is more severely burnt when putting in contact with 1 g of steam at 100°C than water at 100°C.
9. The atmospheric temperature in the cities on sea-coast changes very little. Explain.
Answer: The specific heat capacity of water is much more than the land. It means the seawater warms or cools very slowly compared to the land. When the coastal land warms the air in contact rises up and the air over the sea (also called the sea breeze) rushes towards the land to fill the space. Thus the temperature above the land does not increase much. Similarly when the land cools quickly due to the low temperature the cool land air (land breeze) rushes towards the sea and the warmer sea air fills the gap traveling over the land breeze. So the temperature near the sea-coast changes very little.
10. Should a thermometer bulb have large heat capacity or small heat capacity?
Answer: The thermometer bulb should have a small heat capacity. Otherwise, it will take more heat and pass on to mercury. In calorimetry, we do not take into account the heat transferred to the thermometer. The large heat capacity of the bulb will make the calculations faulty.
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Links to the Chapters
Links to the Chapters
CHAPTER- 21 - Speed of Light
CHAPTER- 20 - Dispersion and Spectra
CHAPTER- 19 - Optical Instruments
CHAPTER- 18 - Geometrical Optics
CHAPTER- 17 - Light Waves
CHAPTER- 16 - Sound Waves
CHAPTER- 15 - Wave Motion and Waves on a String
CHAPTER- 14 - Fluid Mechanics
CHAPTER- 13 - Fluid Mechanics
CHAPTER- 12 - Simple Harmonic Motion
CHAPTER- 11 - Gravitation
CHAPTER- 10 - Rotational Mechanics
CHAPTER- 9 - Center of Mass, Linear Momentum, Collision
CHAPTER- 21 - Speed of Light
CHAPTER- 20 - Dispersion and Spectra
CHAPTER- 19 - Optical Instruments
CHAPTER- 18 - Geometrical Optics
CHAPTER- 17 - Light Waves
CHAPTER- 16 - Sound Waves
CHAPTER- 15 - Wave Motion and Waves on a String
CHAPTER- 14 - Fluid Mechanics
CHAPTER- 13 - Fluid Mechanics
CHAPTER- 12 - Simple Harmonic Motion
CHAPTER- 11 - Gravitation
CHAPTER- 10 - Rotational Mechanics
CHAPTER- 9 - Center of Mass, Linear Momentum, Collision
CHAPTER- 8 - Work and Energy
Click here for → Question for Short Answers
Click here for → OBJECTIVE-I
Click here for → OBJECTIVE-II
Click here for → Exercises (1-10)
Click here for → Question for Short Answers
Click here for → OBJECTIVE-I
Click here for → OBJECTIVE-II
Click here for → Exercises (1-10)
Click here for → Exercises (11-20)
Click here for → Exercises (21-30)
Click here for → Exercises (31-42)
Click here for → Exercise(43-54)
Click here for → Exercises (21-30)
Click here for → Exercises (31-42)
Click here for → Exercise(43-54)
CHAPTER- 7 - Circular Motion
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Click here for → OBJECTIVE-I
Click here for → OBJECTIVE-II
Click here for → EXERCISES (1-10)
Click here for → EXERCISES (11-20)
Click here for → EXERCISES (21-30)
CHAPTER- 6 - Friction
Click here for → Questions for Short Answer
Click here for → OBJECTIVE-I
Click here for → OBJECTIVE-II
Click here for → EXERCISES (1-10)
Click here for → EXERCISES (11-20)
Click here for → EXERCISES (21-30)
CHAPTER- 6 - Friction
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Click here for → Questions for Short Answer
Click here for → OBJECTIVE-I
Click here for → Friction - OBJECTIVE-II
Click here for → EXERCISES (1-10)
Click here for → Exercises (11-20)
Click here for → EXERCISES (21-31)
Click here for → OBJECTIVE-I
Click here for → Friction - OBJECTIVE-II
Click here for → EXERCISES (1-10)
Click here for → Exercises (11-20)
Click here for → EXERCISES (21-31)
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CHAPTER- 5 - Newton's Laws of Motion
Click here for → QUESTIONS FOR SHORT ANSWER
Click here for → QUESTIONS FOR SHORT ANSWER
Click here for→ Newton's laws of motion - Objective - I
Click here for → Newton's Laws of Motion - Objective -II
Click here for → Newton's Laws of Motion-Exercises(Q. No. 1 to 12)
Click here for→ Newton's laws of motion - Objective - I
Click here for → Newton's Laws of Motion - Objective -II
Click here for → Newton's Laws of Motion-Exercises(Q. No. 1 to 12)
Click here for→Newton's Laws of Motion,Exercises(Q.No. 13 to 27)
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CHAPTER- 4 - The Forces
The Forces-
"Questions for short Answers"
Click here for "The Forces" - OBJECTIVE-I
Click here for "The Forces" - OBJECTIVE-II
Click here for "The Forces" - Exercises
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CHAPTER- 3 - Kinematics - Rest and Motion
Click here for "Questions for short Answers"
Click here for "OBJECTIVE-I"
Click here for EXERCISES (Question number 1 to 10)
Click here for EXERCISES (Question number 11 to 20)
Click here for EXERCISES (Question number 21 to 30)
Click here for EXERCISES (Question number 31 to 40)
Click here for EXERCISES (Question number 41 to 52)
CHAPTER- 2 - "Physics and Mathematics"
CHAPTER- 2 - "Physics and Mathematics"
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