Consider two cylindrical conductors made of the same ohmic material. V1 ~E1 I1 ℓ1 r1 b V2 ~E2 I2 ℓ2 r2 b If rho2 = rho1 , r2 = 2 r1 , ℓ2 = 2 ℓ1 , and V2 = V1 , find the ratio R2 R1 of the resistances.

Describe the path of a ray that approaches a mirror parallel to the principal axis.

Carbon 14 is a naturally occurring stable

4r-134a enters the condenser of a residential heat pump at 800 kpa and 50°c at a rate of 0.022 kg/s and leaves at 750 kpa subcooled by 3°c. the refrigerant enters the compressor at 200 kpa superheated by 4°c determine (a) the isentropic efficiency of the compressor, (b) the rate of heat supplied to the heated room, and (c) the cop of the heat pump. also, determine (d) the cop and rate of heat supplied to the heated room if this heat pump operated on the ideal vapor-compression cycle between the pressure limits of 200 and 800 kpa. (0.757, 4.37 kw, 5.12, 6.18, 3.91 kw)