<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:
n = 2.0686
Explanation:
When an unpolarized ray of light is reflected on a surface, the reflected ray is partially polarized, complete polarization occurs when it is true that between the transmitted and reflected ray one has 90, the relationship is
n = so tea
let's calculate
n = tan 64.2
n = 2.0686
Answer:
Neptune is approximately 41 times as far from the sun as Venus
Explanation:
Estimate = distance of Neptune from the sun ÷ distance of Venus from the sun = 4.5×10^9 ÷ 1.18×10^8 = 40.9 (approximately 41)
Answer:
<em>the ball travels a distance of 8.84 m</em>
Explanation:
Range: Range is defined as the horizontal distance from the point of projection to the point where the projectile hits the projection plane again.
R = (U²sin2∅)/g.............................. Equation 1
Where R = range, U = initial velocity, ∅ = angle of projection, g = acceleration due to gravity.
<em>Given: U = 10 m/s, ∅ = 60°</em>
<em>Constant: g = 9.8 m/s²</em>
Substituting these values into equation 1
R = [10²×sin(2×60)]/9.8
R = (100sin120)/9.8
R = 100×0.8660/9.8
R = 86.60/9.8
R = 8.84 m
<em>Therefore the ball travels a distance of 8.84 m</em>