Consider two rectangular surfaces perpendicular to each other with a common edge which is 1.6 m long. the horizontal surface is 0.8 m wide and the vertical surface is 1.2 m high. the horizontal surface has an emissivity of 0.75 and is maintained at 400 k. the vertical surface is black and is maintained at 550 k. the back sides of the surfaces are insulated. the surrounding surfaces are at 290 k, and can be considered to have an emissivity of 0.85. determine the net rate of radiation heat transfers between the two surfaces, and between the horizontal surface and the surroundings

The particles of an ice cube at 0°c (represented by the blue circles) come in contact with the particles of juan’s hand at 37°c (represented by the orange circles). which diagram correctly represents the temperature of the two substances and the direction of heat flow?

To understand the electric potential and electric field of a point charge in three dimensions consider a positive point charge q, located at the origin of three-dimensional space. throughout this problem, use k in place of 14? ? 0. part adue to symmetry, the electric field of a point charge at the origin must point from the origin. answer in one word. part bfind e(r), the magnitude of the electric field at distance r from the point charge q. express your answer in terms of r, k, and q. part cfind v(r), the electric potential at distance rfrom the point charge q. express your answer in terms of r, k, and q part dwhich of the following is the correct relationship between the magnitude of a radial electric field and its associated electric potential ? more than one answer may be correct for the particular case of a point charge at the origin, but you should choose the correct general relationship. a)e(r)=dv(r)drb)e(r)=v(r)rc)e(r)=? dv(r)drd)e(r)=? v(r)r

In which of these cases are the two wave points considered to be in phase with each other?