Suppose a spaceship runs out of fuel near a star. The crew erects a square, whit

Question

Suppose a spaceship runs out of fuel near a star. The crew erects a square, white sail 7.06 km on a side, and adjusts it so it faces the star so the photons hit the sail head-on. At their current distance the intensity of the starlight at the ship's location is 6380 W/m2. Assume:
- the sail is totally reflective: the photons strike the surface and bounce off at the same speed.
- the central frequency of the photons from the star is the same as the photons from part a.
- the central frequency of the photons from the star is also the average frequency.
i. Find the magnitude of the force exerted by the photons on the sail: F = N
ii. Find the temperature of the star's surface: T = K
iii. If the star is evolving so its surface temperature is rising at 683 K per century, the rate at which the central frequency is changing is: df/dt = Hz/century

Explanation / Answer

(i)force F = I * A / c

=>F = 6380 * (7.06*10^3)^2 / (3*10^8) =1060.007N

(ii)6380=sigma*T^4

=>6380=5.67*10^(-8)*(T^4)

=>T=579.174 K

Related Questions

Navigate

• Browse (All)
• Browse S
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.