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Clue TUTUWI
1. What is the function of kink in a clinical thermometer?
2. What are all the various means used by the pizza delivery man to keep the pizza hot?
3. A person has a white shirt and a black shirt. Which shirt will make him more
comfortable in: a) winter and b) summer? Give reason for your answer.
4. A frying pan made of metal (like aluminium or stainless steel) but the handle of frying
pan is made of plastic or wood. Substantiate.
5. How are heat insulators helpful in a space shuttle?
6. How does coffee/tea or boiling water remain hot for a long time in a thermos flask?
7. Air is a bad conductor of heat. Justify with an example.
8. How does heat energy flow?
9. Why are digital thermometers preferred over mercury thermometer?
10. Why is a room heater placed near the floor and an air conditioner near the ceiling?
11. How does infrared photography help us to see objects in the dark?
12. A box of solar cooker is painted black from inside. Justify.
13. How are the jackets made of melamine beneficial to fire fighters?
14. Ice cubes put inside a thermocol box do not melt fast. Give reason.
15. What is the fastest mode of hear transfer?
Answers
Answer:
Ans1 Specific features of the liquid-in-glass clinical thermometer are: A 'kink' in the glass tube which breaks the mercury as it contracts, storing the highest temperature reading. The glass tube is shaped like a lens to magnify the thin mercury thread. Shaking the thermometer resets the mercury back into the bulb.
Explanation:
ans2-Pizza boy(delivery man ) keep the Pizzas in a box which is made up of hard material from outside an inside it is made of thermocol (polystrene (C8H8)n).Thermocol is a poor conductor of heat so, it niether conducts heat energy to the surroundings nor it absorbs heat energy so the pizza kept in the box made up of thermocol will remain hot for a longer time. The box can be made up of any other material also from inside which is a poor conductor of heat.
ans3-In winter black clothes will make him more comfort because black colour will observe heat faster than white clothes. During winter it will be cold everywhere if we wear black it will be useful to keep our body warm.
b) In summer white clothes will make him comfort because during summer it is very hot in our surrounding white colour will observe the heat slowly than black colour.
ans4-frying pan is ade up of metal because aluminum or stainless steel heats faster and better. Handle is made of plastic or wood because they won't absorb heat
ans5-Air and silica glass are both extremely poor conductors of heat, and thus great insulators. That's why you can touch them after coming out of a super-hot oven. On the Space Shuttle, they protected the aluminum hull from the heat of reentry.
ans7-In addition to Dennis' answer, air is a poor conductor because its molecules are not in continuous contact with one another unlike a solid. Heat by conduction passes more quickly in a solid because the molecules' vibrations immediately affect their neighbours.
ans8-Heat can flow from one place to another, like all kinds of energy. ... Heat can flow in a vacuum by process called radiation, where heat transfers through electromagnetic waves. Heat flows in solids by conduction, where two objects in contact with each other transfer heat between them.
ans9-Digital thermometers provide faster results
Mercury thermometers are designed utilizing the idea that mercury expands with heat. ... Mercury is used because it remains liquid throughout various temperatures as opposed to water, which freezes in colder temperatures.
ans10-HEATER is placed near the floor because hot air rises up and the room will be heatness will spread even. The density of air depends upon the temperature. ... So it is placed near the ceiling because the cool ( high density ) air tends to settle downwards.
ans11-Thermal infrared cameras can see people in complete darkness because warm objects (actually, anything hotter than absolute zero) emit blackbody radiation. Infra-red is the shortest wavelength component of that radiation, and so gives the best resolution.
ans12-This property is used in solar cooker where sunlight beats on the device and due to its black color more heat is absorbed. Solar cooker are painted black to maximize the absorption of heat from the sun. Explanation: Solar cooker is a device that uses the solar energy to cook the food present inside it.
ans13-The plastic used to make uniform of fireman is Melamine because,
Melamine is a fire retardant plastic, which resist the spread of fire. It is used in the uniform of fireman for the protection of human body form heat hazards.
It is also use in airplanes, buses etc. to prevent the spread of fire
ans14-IThermocol box is made up of polystyrene ,a kind of synthetic plastic which is a bad conductor of heat. Hence prevents the flow of heat from surrounding air entering into box. As it acts as insulator for transmission of heat, Ice kept in thermocol does not melt fast and retains coolness for longer time.
Answer:15 Radiation is the fastest mode of transfer of heat, because radiation travels at the speed of light, which is very quick. The slowest mode of transfer of heat is conduction because it takes place from particle to particle.Aug 20, 2013