Answer:
T=5797.8 K
Explanation:
Given that
Power P = 3.9 x 10²⁶ W
Radius ,r= 6.96 x 10⁸ m
We know that ,From Plank's law
P = σ A T⁴
σ = 5.67 x 10 ⁻⁸
A= Area ,T= Temperature ( in Kelvin)
Now by putting the values
T=5797.8 K
The temperature of surface will be 5797.8 K
Answer:
14.0351 years
Explanation:
80km / 5.7km per year = 14.0351 years
Answer:
ΔL = 1.2 10⁻³ m
Explanation:
The expression for thermal expansion is
ΔL = α L₀ ΔT
in this case it indicates that the length is L₀ = 5 m for T₀ = 20C the final temperature is T_f = 40 C
the table shows the value of thermal expansion for steel α = 12 10⁻⁶ C⁻¹
let's calculate
ΔL = 12 10⁻⁶ 5 (40 -20)
ΔL = 1.2 10⁻³ m
Answer:
the work converted to thermal energy is 40 J.
Explanation:
Given;
work done by the physicist,w = 100 J
height through which the book is raised, h = 0.2 m
efficiency of machine = 60% = 0.6
The useful work done by the machine is calculated as;
useful work = 0.6 x 100 = 60 J
The wasted energy = 100 J - 60 J
The wasted energy = 40 J
The wasted energy by the machine is possibly converted to thermal energy by the frictional part of the machine.
Therefore, the work converted to thermal energy is 40 J.