What causes an electromagnet to create a magnetic field? A. The Earth's magnetic field.

B. The poles are attracted to each other.

C. The iron is wrapped with a coiled wire.

D. There is a current flowing through the wire.

Ineed the answers for these promblems i have

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

Can anyone plz answer any of these. even if its one it will