All of the stars that are dwarfs are similar in size (they are small), what makes them different from each other? a) luminosity
b) Temperature
c) size
d) life span ​

Consider a 1000 w iron whose base plate is made of 0.5 cm thick aluminum alloy 2024-t6 (ρ = 2770 kg/m3 and cp = 875 j/kg°c). the base plate has a surface area of 0.03 m2. initially, the iron is in thermal equilibrium with the ambient air at 22°c. assuming 90% of the heat generated in the resistance wires is transferred to the plate, determine the minimum time needed for the plate temperature to reach 200°c.

Convection currents are caused by differences in what two things?

Which of the following is another term for a planned economy