<h2>
Answer: 0.17</h2>
Explanation:
The Stefan-Boltzmann law establishes that a black body (an ideal body that absorbs or emits all the radiation that incides on it) "emits thermal radiation with a total hemispheric emissive power proportional to the fourth power of its temperature":
(1)
Where:
is the energy radiated by a blackbody radiator per second, per unit area (in Watts). Knowing 
is the Stefan-Boltzmann's constant.
is the Surface area of the body
is the effective temperature of the body (its surface absolute temperature) in Kelvin.
However, there is no ideal black body (ideal radiator) although the radiation of stars like our Sun is quite close. So, in the case of this body, we will use the Stefan-Boltzmann law for real radiator bodies:
(2)
Where
is the body's emissivity
(the value we want to find)
Isolating
from (2):
(3)
Solving:
(4)
Finally:
(5) This is the body's emissivity
Answer:
0.625m
Explanation:
Now Velocity of a wave ,V = frequency × wavelength
Wavelength =velocity /frequency
=500/800 =0.625m
Answer:
7.59Ns
Explanation:
Given parameters:
Force = 1360N
Time of contact = 5.85 x 10⁻³s
Unknown:
Impulse = ?
Solution:
The impulse of the ball is given as:
Impulse = Force x time
Impulse = 1360 x 5.85 x 10⁻³ = 7.59Ns
Answer:
The answer is A .
Explanation:
Ore is a rock that requires mining .