Size of a Light-Bulb Filament. The operating temperature of a tungsten filament in an incandescent light bulb is 2450 K, and its emissivity is 0.350. Find the surface area of the filament of a 150 W bulb if all the electrical energy consumed by the bulb is radiated by the filament as electromagnetic waves.

The sun has a temperature of 6000 K and a radius of 6.07 x 10^18 m^2. What is the heat current if it has an emissivity of 1. The Stefan-Boltzmann constant is 5.67 x 10^-8 W/m?K4 8.89 x 10^26 W O 2.76 x 10^25 w O 1.98 x 10^7 W O 4.46 x 10^26 w

A 19 century lab technician is testing possible metals for bulb filaments. A tantalum filament with a surface area of 0.370 mm and an emissivity of 0.976 radiates 0.80 W of light. Determine the filament's temperature (in K). The melting point for tantalum is 3269 K.

A radiant heating lamp has a surface temperature of 1000 K with ε = 0.8. How large a surface area is needed to provide 250 W of radiation heat transfer?

An incandescent light bulb has a tungsten filament that is heated to a temperature of 3.20 × 103 K when an electric current passes through it. If the surface area of the filament is approximately 1.00 × 10−4 m2 and it has an emissivity of 0.360, what is the power radiated by the bulb?The Stefan–Boltzmann constant (σ) is 5.670 × 10−8 W/(m2·K4).

A person is standing outdoors in the shade where the temperature is 33 °C. What is the radiant energy absorbed per second by his head when it is covered with hair? The surface area of the hair (assumed to be flat) is 170 cm2 and its emissivity is 0.85.

Please help! A student in a lecture hall has 0.310 m^2 of skin (arms, hands, and head) exposed. The skin is at 34.0°C and has an emissivity of 0.970. The temperature of the room is 20.2°C (air, walls, ceiling, and floor all at the same temperature). The Stefan-Boltzmann constant is 5.670 x 10-8 w/ (m2. k4 ). a) at what rate does the skin emit thermal radiation? b) at what rate does the skin absorb thermal radiation? THANK U

Sirius B is a white star that has a surface temperature (in kelvins) that is four times that of our sun. Sirius B radiates only 0.040 times the power radiated by the sun. Our sun has a radius of 6.96 × 108 m. Assuming that Sirius B has the same emissivity as the sun, find the radius of Sirius B. RSB= O

The next four questions use this description.  Our Sun has a peak emission wavelength of about 500 nm and a radius of about 700,000 km. Your dark-adapted eye has a pupil diameter of about 7 mm and can detect light intensity down to about 1.5 x 10-11 W/m2.  Assume the emissivity of the Sun is equal to 1. First, given these numbers, what is the surface temperature of the Sun in Kelvin to 3 significant digits? What is the power output of the Sun in moles of watts?  (in other words, take the number of watts and divide it by Avogadro's number) Assuming that all of the Sun's power is given off as 500 nm photons*, how many photons are given off by the Sun every second? Report your answer to the nearest power of 10 (e.g. if you got 7 x 1024, give your answer as 25).