Heat and temperature
Short questions:
1. Distinguish between heat and temperature?
2. Distinguish between heat and work?
3. When two bodies A and B are brought in contact, heat flows from body B to A. Which is at higher temperature?
4. Why is mercury used commonly as a thermometric substance? Give two reasons.
5. What is thermal equilibrium? Can two object not in contact ever be in thermal equillibrium?
6. State Zeroth law of thermodynamics? Define temperature on the basis of Zeroth law of thermodynamics?
7. Why two objects in thermal contact come in thermal equilibrium?
8. Which physical quantity determines the direction of flow of heat?
9. Is it necessary that when you add heat to a substance, there is increase in temperature of substance?
10. What are the effects of heat?
11. When a solid is heated, what is the effect on its (i) volume (ii) density and (ii) mass ?
12. What is thermometry and what do you mean by sensitivity of thermometer?
13. Define upper fixed and lower fixed points of thermometer?
14. Write relationship between different temperature scales?
15. Write short note on absolute zero temperature?
16. Water is cheap and available everywhere but it is not used as thermometric substance. Why?
17. Frozen water pipe often bursts; will a mercury thermometer break if the temperature of thermometer is brought below the freezing point of mercury?
18. Write the differences between mercury and alcohol thermometer?
Numerical problems
1. The temperature of a furnace is 2000 oC. what is this temperature on the Kelvin scale and oF scale? 2273 K, 3632 oF
2. At what temperature will the Kelvin scale reading be double the Fahrenheit scale reading? 176.7 oF, 353.4 K
3. Calculate the temperature on Kelvin scale whose value is twice the reading on Celsius scale? 273oC, 546 K
4. What is the change in Celsius degree if it is changed from 44 oF to -56 oF? 55.6 oC
5. If a centigrade thermometer reads 370when a standard Fahrenheit thermometer reads 100o. What is the error in centigrade thermometer? 0.77o
6. A faulty thermometer measures the temperature of an object as 28.2 oC. The UFP an LFP of thermometers are 98.4 oC and -1.2 oC respectively. What is the correct temperature of object? 29.51 oC
7. In an arbitrary scale of temperature, water freezes at 40 oC and boils at 290 oC. Find the boiling point of liquid in this scale if it boils at 62 oC? 195 oC
8. The difference between UFP and LFP is 80 cm. Find the temperature on the celsius scale if the mercury level rises to a height 10.4 cm above LFP? 13 oC
9. A platinum resistance thermometer reads 0 oC when R = 80 Ω and 100 oC when R = 90 Ω. Find the temperature of the platinum scale at which R = 86 Ω? 60 oC
10. Water boils at 100 oC at normal atmospheric pressure. The atmospheric pressure of KTM is 64.5 mm of Hg.
(i) At what temperature would water boil in Kathmandu? 95.7 oC
(ii) At what pressure would water boil at 150 oC? 2.8 atm.
11. A oC and oF thermometer are placed in hot water. The water is then cooled. What fall of temperature will the Fahrenheit thermometer register, when the centigrade thermometer records the fall in temperature as 45 oC. 81 oF
12. A faulty thermometer reads - 2 oC in melting ice and 102 oC in steam at normal pressure (a) What is the correct temperature when the faulty thermometer reads 20 oC? (b) What the faulty thermometer read when the correct temperature is 20 oC? (c) At what temperature is its reading exactly correct? 21.2oC, 18.8 oC, 50 oC