Answer:
2.63 x 10^18
Explanation:
A = 1 cm^2 = 1 x 10^-4 m^2
λ = 10,000 nm = 10,000 x 10^-9 m = 10^-5 m
T = 37 degree C = 37 + 273 = 310 k
Energy of each photon = h c / λ
where, h is the Plank's constant and c be the velocity of light
Energy of each photon = (6.63 x 10^-34 x 3 x 10^8) / 10^-5 = 1.989 x 10^-20 J
Energy radiated per unit time = σ A T^4
Where, σ is Stefan's constant
Energy radiated per unit time = 5.67 x 10^-8 x 10^-4 x 310^4 = 0.05236 J
Number of photons per second = Energy radiated per unit time / Energy of
each photon
Number of photons per second = 0.05236 / (1.989 x 10^-20) = 2.63 x 10^18
Answer:
c)They can also be simultaneous in S if their separation is zero.
Explanation:
By relativity theory, we can say two events when seen from two different reference frames can only be simultaneous when they are at the same space location and occur simultaneously in at least one reference frame, therefore when Frame S′ usually passes Frame S. Two occurrences in S′ are simultaneous, therefore these occurrences can be simultaneous in S when their separation is 0 (that is they are at the same location)
And therefore option c. If their separation is zero, they can also be simultaneous in S.
Answer: hydroelectric dams
Explanation: Enormous energy is stored in water held back by hydroelectric dams. The energy is transformed into (a form of kinetic energy) as it falls across the dam. The falling water strikes the blades of a turbine and makes them spin, and the then turns the shaft of a generator.
Well, st first we should find <span>initial momentum for the first person represented in the task which definitely must be :
</span>
And then we find the final one :
Then equate them together :
So we can get the velocity, which is
In that way, according to the main rules of <span>conservation of momentum you can easily find the solution for the second person.
Regards!</span>
Answer:
Conduction, Convection and Radiation
Explanation:
Hope this helps!