② In Figure B, when the switch is placed between 1 and 2, the motor works and blows cold air; When the switch is placed between 2 and 3, both the heating wire and the motor work and blow out hot air.
A: The circuit of B is more in line with the actual situation.
(2)① When hot air is blown, the heating wire is connected in parallel with the motor, and pTotal = heating wire +pCold,
Power of heating wire: heating wire = pTotal-pTotal =460W-20W=440W.
② According to the deformation of P=U2R, R=U2P is obtained.
The ∴ resistance of the heating wire r = u2p = (220v) 2440w =110ω.
(3)1min, the heat generated by the current passing through the heating wire.
Q=P Heating wire t=440W×60s=2.64× 104J
Answer: When the hair dryer blows hot air normally, the power of the heating wire is 440W, the resistance is110Ω, and the heat generated by the current through the heating wire within 1min is 2.64× 104J. .