Physics Heat & Thermodynamics Level: High School
n mol of an ideal gas are compressed isothermally from an initial volume V1 to a final volume V2 .What is the change in entrophy
Change in S=n*k*In (v2/v1)
Change in S=n* (Cv/T)
Change in S=n*Cv*Integral of dT/T
Change in S=n*R*In(V2/V1)
Change in S=n*R*T*In(V2/V1)
Physics Heat & Thermodynamics Level: High School
On a hot day , a Florida home is kept cool by an air conditioner . The outside temperature is 36.6 degreeC and the interior of the home is 15.2 degreeC . If 152 kJ/h of heat is removed from the house . What is the minimum power that must be provided to the air-conditioner ? Answer in units of kJ/h .
Physics Heat & Thermodynamics Level: High School
The radius of the sun is 6.96 x 10^8 m and the total power output from its surface is 2.51 x 10^26w .Assuming that sun acts like a black body , calculate its surface temperature .
What is the maximum wavelength of radiation from the sun ?
Physics Heat & Thermodynamics Level: High School
(a) A heat source has its radiation maximum when the wavelength is 1.8 micro m . Calculate the temperature of the heat source .
(b)If the absolute temperature of a black of body is doubled , by what factor does the total power increase ?
(c)A tungsten filament of an incandescent bulb is a wire diameter 0.1 cm . length 10 cm and acts like a black body . Calculate the power radiated from the surface of the filament when its temperature is 2000 degreeK . Neglect any radiation from the two contact (cross –sectional area )points .
Physics Heat & Thermodynamics Level: High School
(a) How much energy is required to change 40g of ice from ice at -10 degreeC to steam at 110 degreeC ?A combination of (0.25 kg of water at 20degreeC), (0.4kg of aluminium at 26 degreeC) and (0.1 kg of copper at 100 degreeC) is mixed in an insulated container and allowed to come to thermal equilibrium . Ignoring any energy transfer to or from the container , determine the final temperature of the ‘mixture’
Physics Heat & Thermodynamics Level: High School
(a) A bar of gold is in thermal contact with a bar of silver of the same length and area . The compound bar is well lagged with one end maintained at 80 degreeC while the opposite end is maintained at 30 degreeC . When the energy transfer reaches a steady state , what is the temperature of the junction ?
(b) The temperature of a silver bar rises by 10 degreeC when it absorbs 1.23 kJ of heat energy. If the mass of the bar is 525 g find the specific heat capacity of silver .
Physics Heat & Thermodynamics Level: High School
(a) A student eats a meal of 2000 kcal (kilocalories ) . He wishes to do an equivalent amount of work in the gym by lifting a 50 kg barbell . How many times must he raise the barbell to expend this amount of energy assuming that he raised it from ground level to head level a distance of 2m and that he regains no energy when he lowers the barbell to the floor ?(b)A glass window pane has an area of 3m^2 and a thickness of 0.6 mm . If the temperature difference between its face is 25 degreeC , what is the rate of energy transfer by conduction through the window ? (Thermal conductivity of glass is 0.8 W/m degree C .)
Physics Properties Of Matter Level: High School
A U-tube of uniform cross-sectional area and open to the atmosphere is partially filled with mercury . Water is then poured into both arms . If the equilibrium configuration of the tube is as shown in the figure at “click here” With h2 = 1.00 cm , determine the values of h1 .
Physics Properties Of Matter Level: High School
A large tank is partly full of pure water , and gauge pressure of 3.0 at m is maintained in the upper part of the tank by compressed air . A small hole is drilled in the tank 8.0 m below the free surface of the water . Calculate the velocity of the water emerging from the hole . (Note : The pressure given above the water is a gauge pressure , not an absolute pressure . The pressure outside the tank is , of course , different from the pressure inside the tank .)
Physics Properties Of Matter Level: High School
What is the net upward force on an airplane wing of area 20 m^2 if the speed of flow is 300 m/s across the top of the wing and 280 m/s across the bottom ?
Physics Properties Of Matter Level: High School
A steel safe of weight 1.00 x 10^4 N . is being raised to the top of a building. The steel cable to be used was only 15 m long and so an additional 7 m length of another cable had to be used . If both cables have a diameter of 1.00 cm , and the total stretch of both cables put together is 2.35 cm , What is the Young’s modulus of the second cable ? The weight of both cables is negligible compared to that of the safe .
Physics Properties Of Matter Level: High School
Pressure
Suppose that a girl weighing 125 pounds is wearing “spike” heel shoes . If she surface of the heel in contact with th floor corresponds to a square measuring ¼ on each side , and if she stands momentarily with all her weight on one heel , what is the pressure she exerts on the floor ?125 lbs/in^2
500 lbs/in^2
1000 lbs/in^2
1250 lbs/in^2
2000 lbs/in^2
Physics Properties Of Matter Level: High School
Archimedes Principle
A glass container is half-filled with mercury , and a steel ball is floating on the mercury . If water is then poured on top of the steel ball and mercury , filling the glass , What will happen to the steel ball ?a. It will float higher in the mercury .
b. It will float at the same height . v
c. It will float lower in the mercury .
d. It will sink to the bottom of the mercury .
when water is poured , there will be an up thrust (or apparent loss in weight) of the steel ball due to the water displaced by it . Thus , steel ball will becomes slightly lighter and so it will displace less of Hg to counter balance its weight .
Physics Properties Of Matter Level: High School
Elasticity
When a force F is applied to a certain rod , there is a 1 cm change in length . If that same force is applied to a rod that is three times bigger in each dimension , what will be the change in length ?9 cm
3 cm
1 cm
0.33 cm
0.667 cm
Physics Properties Of Matter Level: High School
A large stone is resting on the bottom of the swimming pool . The normal force of the bottom of the pool on the stonea. is equal to the weight of the stone
b. is equal to the weight of the water displaced
c. is equal to the sum of the weight of the stone and the weight of the displaced water.
d. is equal to the difference between the weight of the stone and the weight of the displaced water.