A perfectly black sphere 18.0 cm in diameter is held at a temperature of 215°C. (? = 5.670 × 10-8 W/m2 ? K4, Wien displacement law constant is 2.90 × 10-3 m ? K, h = 6.626 × 10-34 J ? s, c = 3.00 × 108 m/s)
(a) Near what wavelength does this sphere radiate most strongly?
(b) If all the radiated energy were at the wavelength found in part (a), how many photons would the sphere emit each second?
What will be an ideal response?
Answer: (a) 5.94 µm (b) 9.79 × 1021 photons
You might also like to view...
A transverse periodic wave is represented by the equation y(z, t) = 2.0 cm sin(1,200 rad/s t - 20.0
z). Another transverse wave is represented by the equation y(z, t) = 2.0 cm sin(1,200 rad/s t - 20.0
z). What is the equation that represents the superposition of the two waves?
A. y(z, t) = 4.0 cm sin(1,200 rad/s t - 20.0
z)
B. y(x, t) = 4.0 cm sin(1,200 rad/s t) cos20.0x)
C. y(x, t) = +4.0 cm cos(1,200 rad/s) sin(20.0 x)
D. y(x, t) = +4.0 cm cos(1,200 rad/s) + (20.0x)
A proton's rest mass is 1.67 × 10?27 kg. Calculate its total energy when it is accelerated to a speed of 0.80c.
A. 1.5 × 10?10 J B. 1.0 × 10?10 J C. 2.5 × 10?10 J D. 2.0 × 10?10 J E. 7.5 × 10?10 J
An aluminum wire and a steel wire, each of length 2.0 m, are hung from the ceiling. A 5.0-kg mass is suspended from the lower end of each wire. The aluminum wire has a diameter of 2.2 mm
What must be the diameter of the steel wire if it is to stretch the same distance as the aluminum wire, so that the two wires maintain equal lengths after the masses are attached? Young's modulus for aluminum is 0.70 × 1011 Pa and for steel it is 2.0 × 1011 Pa.
Suppose you are out on a frozen lake, where there is no friction. Which of the following would start you moving towards the shore?
A. Removing a shoe and throwing it towards the shore B. Shouting at someone on the shore C. Removing a shoe and throwing it away from the shore D. None of these choices would work