Aprimitive space heater consists of a 10.0 cm radius iron ball through which electrical current was passed in order to heat the ball, and subsequently the surrounding air. if the temperature of the iron ball is kept at 510 k, and the room temperature is 20oc, what power is radiated into the room? assume the ball is a perfect blackbody.
a. 110w
b. 480w
c. 140w
d. 430w

Consider a hydrogen atom in the ground state. what is the energy of its electron? =e= jj now consider an excited‑state hydrogen atom. what is the energy of the electron in the =5n=5 level? =e5= j

Acarpenter builds an exterior house wall with a layer of wood 2.9 cm thick on the outside and a layer of styrofoam insulation 2.3 cm thick on the inside wall surface. the wood has k=0.080w/(m⋅k), and the styrofoam has k= 0.010 w/(m⋅k). the interior surface temperature is 19.0 ∘c , and the exterior surface temperature is -15.0 ∘c . a.)what is the temperature at the plane where the wood meets the styrofoam? celsius b.)what is the rate of heat flow per square meter through this wall? /m^2

An object in mechanical equilibrium is an object