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Heat and TheromdynamicsQuestion and Answers: Page 3

Question Number 42497 Answers: 0 Comments: 1

A body cools from 90°C to 40°C in 2 minutes at a temperature,20°C of the surrounding.Calculate the temperature of the body after another 5 minutes.

$${A}\:{body}\:{cools}\:{from}\:\mathrm{90}°{C}\:{to}\:\mathrm{40}°{C}\:{in} \\ $$$$\mathrm{2}\:{minutes}\:{at}\:{a}\:{temperature},\mathrm{20}°{C} \\ $$$${of}\:{the}\:{surrounding}.{Calculate}\:{the} \\ $$$${temperature}\:{of}\:{the}\:{body}\:{after} \\ $$$${another}\:\mathrm{5}\:{minutes}. \\ $$

Question Number 42262 Answers: 1 Comments: 0

Heat is supplied at a rate of 500W to a pressure cooker containing water and fitted with a safety valve.Steam escape such that water is lost at 12g/min.If the heat is supplied at 900W,water is lost at 20g/min.Calculate the specific latent heat of steam.

$${Heat}\:{is}\:{supplied}\:{at}\:{a}\:{rate}\:{of}\:\mathrm{500}{W} \\ $$$${to}\:{a}\:{pressure}\:{cooker}\:{containing} \\ $$$${water}\:{and}\:{fitted}\:{with}\:{a}\:{safety}\: \\ $$$${valve}.{Steam}\:{escape}\:{such}\:{that}\: \\ $$$${water}\:{is}\:{lost}\:{at}\:\mathrm{12}{g}/{min}.{If}\:{the} \\ $$$${heat}\:{is}\:{supplied}\:{at}\:\mathrm{900}{W},{water}\:{is} \\ $$$${lost}\:{at}\:\mathrm{20}{g}/{min}.{Calculate}\:{the} \\ $$$${specific}\:{latent}\:{heat}\:{of}\:{steam}. \\ $$$$ \\ $$

Question Number 42261 Answers: 1 Comments: 1

How much sweat must evaporate from the surface of 150kg of human body to be able to cool the human by 2°C.(assume C=3.35J/g/K for human and L=2.5mJ/kg for water at body temperature)

$${How}\:{much}\:{sweat}\:{must}\:{evaporate} \\ $$$${from}\:{the}\:{surface}\:{of}\:\mathrm{150}{kg}\:{of}\:{human} \\ $$$${body}\:{to}\:{be}\:{able}\:{to}\:{cool}\:{the}\:{human} \\ $$$${by}\:\mathrm{2}°{C}.\left({assume}\:{C}=\mathrm{3}.\mathrm{35}{J}/{g}/{K}\:{for}\right. \\ $$$${human}\:{and}\:{L}=\mathrm{2}.\mathrm{5}{mJ}/{kg}\:{for} \\ $$$$\left.{water}\:{at}\:{body}\:{temperature}\right) \\ $$

Question Number 42131 Answers: 1 Comments: 1

Determine the total translational energy of two litres of oxygen gas held at a temperature of 0°C and pressure of one atmosphere.

$${Determine}\:{the}\:{total}\:{translational} \\ $$$${energy}\:{of}\:{two}\:{litres}\:{of}\:{oxygen}\:{gas} \\ $$$${held}\:{at}\:{a}\:{temperature}\:{of}\:\mathrm{0}°{C}\:{and}\: \\ $$$${pressure}\:{of}\:{one}\:{atmosphere}. \\ $$$$ \\ $$

Question Number 42128 Answers: 0 Comments: 2

Calculate the density of 1 mole of oxygen at a pressure of 4×10^4 Nm^(−2) and temperature of 273.2K.

$${Calculate}\:{the}\:\:{density}\:{of}\:\mathrm{1}\:{mole}\:{of} \\ $$$${oxygen}\:{at}\:{a}\:{pressure}\:{of}\:\mathrm{4}×\mathrm{10}^{\mathrm{4}} {Nm}^{−\mathrm{2}} \\ $$$${and}\:{temperature}\:{of}\:\mathrm{273}.\mathrm{2}{K}. \\ $$

Question Number 42125 Answers: 0 Comments: 6

If a petrol tank costs σ2000.00 to fill it up at 10°C,how much extra must I pay to fill up the tank at 50°C if the petrol costs σ50.00 per litre and its cubic expansivity is 9.5×10^(−4) K^(−1) ?

$${If}\:{a}\:{petrol}\:{tank}\:{costs}\:\sigma\mathrm{2000}.\mathrm{00}\:{to} \\ $$$${fill}\:{it}\:{up}\:{at}\:\mathrm{10}°{C},{how}\:{much}\:{extra} \\ $$$${must}\:{I}\:{pay}\:{to}\:{fill}\:{up}\:{the}\:{tank}\:{at}\:\mathrm{50}°{C} \\ $$$${if}\:{the}\:{petrol}\:{costs}\:\sigma\mathrm{50}.\mathrm{00}\:{per}\:{litre} \\ $$$${and}\:{its}\:{cubic}\:{expansivity}\:{is} \\ $$$$\mathrm{9}.\mathrm{5}×\mathrm{10}^{−\mathrm{4}} {K}^{−\mathrm{1}} ? \\ $$

Question Number 41888 Answers: 0 Comments: 5

The length of mercury column in a mercury-in-glass thermometer is 4cm at triple point.What is the length of the column when the scale indicates temperature of 560K.

$${The}\:{length}\:{of}\:{mercury}\:{column}\:{in} \\ $$$${a}\:{mercury}-{in}-{glass}\:{thermometer} \\ $$$${is}\:\mathrm{4}{cm}\:{at}\:{triple}\:{point}.{What}\:{is}\:{the} \\ $$$${length}\:{of}\:{the}\:{column}\:{when}\:{the} \\ $$$${scale}\:{indicates}\:{temperature}\:{of} \\ $$$$\mathrm{560}{K}. \\ $$

Question Number 40498 Answers: 1 Comments: 0

A gas at 17° has the ratio of its initial to final volume as 25 with initial pressure of 2×10^5 Nm^(−2) .Calculate the final pressure and temperature after compression.(γ=1.5)

$${A}\:{gas}\:{at}\:\mathrm{17}°\:{has}\:{the}\:{ratio}\:{of}\:{its}\:{initial} \\ $$$${to}\:{final}\:{volume}\:{as}\:\mathrm{25}\:{with}\:{initial} \\ $$$${pressure}\:{of}\:\mathrm{2}×\mathrm{10}^{\mathrm{5}} {Nm}^{−\mathrm{2}} .{Calculate} \\ $$$${the}\:{final}\:{pressure}\:{and}\:{temperature} \\ $$$${after}\:{compression}.\left(\gamma=\mathrm{1}.\mathrm{5}\right) \\ $$

Question Number 39237 Answers: 0 Comments: 1

Calculate the triple point for an electrical resistance thermometer, assuming the ratio of resistance at the triple point to that at initial point is 2.0.

$${Calculate}\:{the}\:{triple}\:{point}\:{for}\:{an} \\ $$$${electrical}\:{resistance}\:{thermometer}, \\ $$$${assuming}\:{the}\:{ratio}\:{of}\:{resistance} \\ $$$${at}\:{the}\:{triple}\:{point}\:{to}\:{that}\:{at}\:{initial} \\ $$$${point}\:{is}\:\mathrm{2}.\mathrm{0}. \\ $$

Question Number 39236 Answers: 0 Comments: 3

If a petrol tank costs $2000.00 to fill it up at 10°C ,how much extra dollar must I pay to fill up the tank at 50°C,if the petrol costs $50.00 per litre and its cubic expansivity is 9.5×10^(−4) K^(−1) ?

$${If}\:{a}\:{petrol}\:{tank}\:{costs}\:\$\mathrm{2000}.\mathrm{00}\:{to} \\ $$$${fill}\:{it}\:{up}\:{at}\:\mathrm{10}°{C}\:,{how}\:{much}\:{extra} \\ $$$${dollar}\:{must}\:{I}\:{pay}\:{to}\:{fill}\:{up}\:{the}\:{tank} \\ $$$${at}\:\mathrm{50}°{C},{if}\:{the}\:{petrol}\:{costs}\:\$\mathrm{50}.\mathrm{00} \\ $$$${per}\:{litre}\:{and}\:{its}\:{cubic}\:{expansivity} \\ $$$${is}\:\mathrm{9}.\mathrm{5}×\mathrm{10}^{−\mathrm{4}} {K}^{−\mathrm{1}} ? \\ $$$$ \\ $$

Question Number 39235 Answers: 0 Comments: 1

The length of a mercury column in a mercury in glass thermometer is 4cm at triple point.What is the length of the column when the scale indicates temperature of 560K.

$${The}\:{length}\:{of}\:{a}\:{mercury}\:{column} \\ $$$${in}\:{a}\:{mercury}\:{in}\:{glass}\:{thermometer} \\ $$$${is}\:\mathrm{4}{cm}\:{at}\:{triple}\:{point}.{What}\:{is}\:{the} \\ $$$${length}\:{of}\:{the}\:{column}\:{when}\:{the} \\ $$$${scale}\:{indicates}\:{temperature}\:{of}\:\mathrm{560}{K}. \\ $$

Question Number 34892 Answers: 0 Comments: 0

Question Number 34891 Answers: 1 Comments: 0

Question Number 32264 Answers: 0 Comments: 1

Question Number 31474 Answers: 1 Comments: 1

A vacuum chamber has a door with surface dimensions 20cm×20cm.How many 70kg men, each exerting a pull equal to his weight,will it take to pull the door open when the chamber is evacuated to a pressure of 0.1 atm?

$${A}\:{vacuum}\:{chamber}\:{has}\:{a}\:{door} \\ $$$${with}\:{surface}\:{dimensions} \\ $$$$\mathrm{20}{cm}×\mathrm{20}{cm}.{How}\:{many}\:\mathrm{70}{kg}\:{men}, \\ $$$${each}\:{exerting}\:{a}\:{pull}\:{equal}\:{to}\:{his} \\ $$$${weight},{will}\:{it}\:{take}\:{to}\:{pull}\:{the} \\ $$$${door}\:{open}\:{when}\:{the}\:{chamber}\:{is} \\ $$$${evacuated}\:{to}\:{a}\:{pressure}\:{of}\:\mathrm{0}.\mathrm{1}\:{atm}? \\ $$

Question Number 31326 Answers: 1 Comments: 1

Question Number 31209 Answers: 1 Comments: 2

Question Number 31114 Answers: 1 Comments: 2

Question Number 27447 Answers: 1 Comments: 0

∫^∞ _0 v^(4 ) e ((−mv^2 )/(2KT))dv solve it

$$\underset{\mathrm{0}} {\int}^{\infty} \:\mathrm{v}^{\mathrm{4}\:} \:\mathrm{e}\:\frac{−\mathrm{mv}^{\mathrm{2}} }{\mathrm{2KT}}\mathrm{dv}\: \\ $$$$\mathrm{solve}\:\mathrm{it} \\ $$

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