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Hello there.
<span>Electromagnetic radiation is:
</span><span>A- energy that is electric and magnetic
</span>
The right answer for the question that is being asked and shown above is that: "1-4-3-2." (main sequence-->red giant-->supergiant-->white dwarf). Assume that all four H-R diagrams below represent a star in different stages of its life, after it starts to fuse hydrogen in its core.
Answer:
a. negative
b. zero
Explanation:
work is the change in the energy of a system due to external forces
work is done when a force moves a load through a distance in the direction of the force
The work done by a force on a system is positive when the force and the force displacement point in the same direction and negative when they point in opposite directions
in the scenario we are considering in the question, the force (the hand) moves the block vertically upwards but the displacement of the block reduces (in the opposite direction) since it decelerates. as such the work done by gravity on the block is negative.
the work done on the block is zero if the system consists of the block and the earth because there is no gravitational force exerted on the system
Answer:
Explanation:
Let hotter star has surface area of A . The cooler star would have surface area 9 times that of hotter star ie 9A , because its radius is 3 times hot star. Let temperature of hot star be T ₁.
Total radiant energy is same for both the star
Using Stefan's formula of black body radiation,
For cold star E = 9A x σ T⁴
For hot star E = A x σ T₁⁴
A x σ T₁⁴ = 9A x σ T⁴
T₁⁴ = (√3)⁴T⁴
T₁ = √3T .
b )
Let the peak intensity wavelength be λ₁ and λ₂ for cold and hot star .
As per wein's law
for cold star , λ₁ T = b ( constant )
for hot star λ₂ √3T = b
dividing
λ₁ T / λ₂ √3T = 1
λ₂ / λ₁ = 1 / √3
