Transmission of heat Questions and Answers

A picture window has dimensions of 1.77 m by 2.68 m and is made of glass 5.14 mm thick. On a winter day, the outside temperature is -20°C, while the inside temperature is a comfortable 19.5°C. At what rate is heat being lost through the window by conduction? kglass = 0.80 W/m.K Round your answer to 2 decimal places.

A 43-cm long cylindrical rod conducts 175 J/s from a furnace at 325°C to a container of boiling water under 1 atmosphere. Compute its diameter if it is made of steel (k = 50.2 W/m-K). Express your answer in cm. Round your answer to 2 decimal places.

A tungsten sphere (r = 1.41 cm) is needed to be maintained at 3314 K. The walls of the enclosure, where it is suspended within, are at 251 K. Ignoring the heat conduction along the supports, calculate the needed power input. The emissivity of tungsten is 0.350. Express your answer in kW. Round your answer to 2 decimal places.

A tungsten sphere (r = 1.08 cm) is needed to be maintained at 3249 K. The walls of the enclosure, where it is suspended within, are at 260 K. Ignoring the heat conduction along the supports, calculate the needed power input. The emissivity of tungsten is 0.350. Express your answer in kW.

Two rooms, each a cube 4 m per side, share a 10.9-cm thick brick wall. Because of a number of 100-W lightbulbs in one room, the air is at 24 deg C, while in the other room it is at 14 deg C. How many of the 100-W bulbs are needed to maintain the temperature difference across the wall? kbrick = 0.84 W/m.K Round your answer to 2 decimal places.

Two 99 sq cm plates which are both 2.21 mm thick are soldered together. Plate A is at 155°C while plate B is at 0°C. Considering the following thermal conductivities, what is the temperature at the soldered junction? k(a) = 43.74 W/m.K k(b) = 59.62 W/m.k Round your answer to 2 decimal places.

One end of an insulated metal rod is maintained at 100 deg C, and the other end is maintained at 0 deg C by an ice-water mixture. The rod is 74 cm long and has a cross-sectional area of 1.25 cm²? What is the thermal conductivity (W/m.K) of the rod if heat current is 4.97 W? Round your answer to 2 decimal places.

A 34-cm long cylindrical rod conducts 188 J/s from a furnace at 344°C to a container of boiling water under 1 atmosphere. Compute its diameter if it is made of steel (k=50.2 W/m K). Express your answer in cm. Round your answer to 2 decimal places.

If left untreated, which of these is the most likely outcome of a binge-eating disorder? O A.Obesity O B.Anorexia nervosa O C.Excessive muscle mass O D.Tooth decay

Two rooms, each a cube 4 m per side, share a 13.9-cm thick brick wall. Because of a number of 100-W lightbulbs in one room, the air is at 20 deg C, while in the other room it is at 9 deg C. How many of the 100-W bulbs are needed to maintain the temperature difference across the wall? Kprick = 0.84 W/m.K Round your answer to 2 decimal places.

A picture window has dimensions of 1.3 m by 2.28 m and is made of glass 5.62 mm thick. On a winter day, the outside temperature is -20°C, while the inside temperature is a comfortable 19.5°C. At what rate is heat being lost through the window by conduction? kglass = 0.80 W/m.K

13. The mass of an object is 229 g- The object requires 20.0J to raise its temperature by 10.0° C. What is the specific heat of the object? 4,580,000 J/kg. K 2000 J/kg-K 0.00110 J/kg . K 8.73 J/kg-K

A sphere has radius 0.30 m, surface emissivity 0.48, and temperature 600 K. Surrounding the sphere is a concentric spherical shell. The inner surface of the shell has radius 0.90 m, emissivity 1.00, and temperature 400 K. At what net rate and direction is heat radiated across the space between the sphere and the shell? The Stefan-Boltzmann constant is 5.67 x 10-8 W/(m². K4). 6.5 kW, inward 8.3 kW, outward 4.0 kW, outward 10.8 kW, inward 18.8 kW, outward

A gas at 100° C fills volume Vo. Part A If the pressure is held constant, by what factor does the volume change if the Celsius temperature is doubled? ▾ Part B If the pressure is held constant, by what factor does the volume change if the Kelvin temperature is doubled?

A X means your answer is close but wrong (do not round off at all unless stated). Specific Heat: (a) How much heat must be removed from a 264 g block of steel to lower its temperature from 80°C to 12°C?

The specific heat c of a solid at low shows temperature dependence according to the relation c = DT3 where D is a constant and I is the temperature in kelvin. A piece of this solid of mass m kg is taken and its temperature is raised from 20K to 30K. The amount of the heat required in the process in energy units is 5 x 10¹ Dm (33/4) × 10¹ Dm (65/4) × 10¹ Dm (5/4) × 104 Dm