The ceiling of a single-family dwelling in a cold climate should have an R-value of 49 ft2 ·F°·h/Btu. To give such insulation, how thick would a layer of (a) polyurethane foam and (b) silver have to be? The thermal conductivity of polyurethane foam is 0.024 W/m·K, and the thermal conductivity of silver is 428 W/m·K.

High schoolphysics 5+3 pts a neon light consists of a glass tube with metal wires at each end. when connected to a high-voltage source, the gas glows. if a fly lands on the glass tube, what will most likely happen? a) the fly will not feel a shock because the glass conducts any free electrons back into the gas. b) electrons will flow directly from the metal wires along the glass and shock the fly. c) the fly will not feel a shock because the glass insulates it from the electrons in the gas and the metal. d) electrons that are moving through the gas will be conducted through the glass and shock the fly.

Positive ions differ from neutral atoms in that

Use the illustration to describe how the electromagnetic spectrum changes as its frequency moves from radio waves to higher energy gamma waves in terms of wavelength and amplitude.