Conductive heat transfer is achieved by (fluid movement, molecular vibration, electromagnetic waves). 1. 2. the (rate, flux) of heat transfer by conduction through a tube wall with thickness ar in the radial direction is const ant at steady state and constant temperature difference even if the wall thickness varies. the rate of heat transfer by conduction across a flat slab can be increased by increasing the slab's (heat 3. capacity, thickness, thermal conductivity). the biot number is a quantitative measure of the relative ratio of (resistances, gradients, temperatures) 4. due to conduction and convection. a (lumped, distributed) system has spatial variations of temperature at any given time. black bodies have perfect (absorptivity, transmissivity, reflectivity). 5. 6. 7. the reciprocity rule states that the product f12a, is equal to (f22a2, f21a2, f12a2). the emissive power of a body is directly proportional to (t, t2, t3, t) 8. for opaque solids, (absorptivity, transmissivity, reflectivity) is zero. 9. 10. heat transfer by radiation between two bodies will be (enhanced, diminished, unaffected) by matter in between them.