Answer:
Two stars (a and b) can have the same luminosity, but different surface area and temperature if the following condition is met:
(T_a^4)(R_a^2) = (T_b^4)(R_b^2)
Explanation:
The luminosity of a star is the total energy that produces in one second. It depends on the size of the star and its surface temperature.
L = σ(T^4)(4πR^2)
L is the luminosity f the star, T is the temperature of the surface of the star and R is its radius.
Two stars can have the same luminosity if the relation between the radius and the surface temperature is maintained.
To see this lets suposed you have 2 stars, a and b, and the luminosities of each one of them:
L_a = σ(T_a^4)(4πR_a^2)
L_b = σ(T_b^4)(4πR_b^2)
you can assume that L_a and L_b are equal:
σ(T_a^4)(4πR_a^2) = σ(T_b^4)(4πR_b^2)
Now, you can cancel the constants:
(T_a^4)(R_a^2) = (T_b^4)(R_b^2)
as long as this relation between a and b is true, then the luminosity can be the same.
45 is 1/8 of a circle so then you take the 24 hours for a full one and divide by 8 24/8=3 3 Hours for a full rotation
The exercise of freedom of expression by some media houses in SA is
being thwarted by the government due to the increase of journalist and reporters
killing for the past years. This clearly shows that the citizen in South Africa
has no freedom to know how their country is performing and how will it affect
them in the long run.
Concrete is not a crystal.
Answer:
It's best to have most of the growth happen in developed countries. This for several reasons:
- Developed countries as a whole have less population, so a population increase in these countries represents less people in absolute numbers.
- Developed countries can invest in green energy more easily. For example, in Germany, 27 percent of energy comes from renewable sources, and in Norway, an oil-exporting country nonetheless, around 30% of cars are electric. They can do this because they are wealthier, and investing in renewable energy can be expensive.
- Developed countries are not likely to grow at high rates anyway. Developed countries are aging fast, their population pyramids are bulky in the middle, and every year, less women are available for giving birth. Developed countries will not grow at high rates in the coming decades unless the receive massive immigration.
