Answer:
A star with 15 solar masses is too big to be a main-sequence star.
The process of heat exchange is involved in the operation of all heat engines.
<u>Explanation:</u>
A heat engine refers as the system which converts thermal or heat and chemical energy into mechanical energy. Then, these can be utilised for mechanical work. This is done by raising the active substances from higher to lower temperature state. In simple words, it produces macroscopic movement from the heat.
For example, when people rub their hands, friction converts mechanical energy (the movement of our hands) into thermal energy (hands warm up). Heat engines work exactly the opposite; they take energy to warm up (in relation to the environment) and release it for movement. This movement is often transformed into electricity by a generator. It shows that there is exchange of heat involved in all of its processes.
Answer:
elastic partial width is 2.49 eV
Explanation:
given data
ER E = 250 eV
spin J = 0
cross-section magnitude σ = 1300 barns
peak P = 20ev
to find out
elastic partial width W
solution
we know here that
σ = λ²× W / ( E × π × P ) ...................1
put here all value
σ = (0.286)² × W × 
/ ( 250 × π × 20 )
1300 × 
= (0.286)² × W × / ( 250 × π × 20 )
solve it and we get W
W = 249.56 × 
so elastic partial width is 2.49 eV
Answer:
21 hours
Explanation:
well 30 x 20 = 600 than 21 = 630
