An office worker uses an immersion heater to warm 349 g of water in a light, covered, insulated cup from 20°C to 100°C in 2.00 minutes. The heater is a Nichrome resistance wire connected to a 120-V power supply. Assume that the wire is at 100°C throughout the 2.00-min time interval. (a) Calculate the average power required to warm the water to 100°C in 2.00 min. (The specific heat of water is 4186 J/kg · °C.)
W

(b) Calculate the required resistance in the heating element at 100°C.
Ω

(c) Calculate the resistance of the heating element at 20.0°C.
Ω

(d) Derive a relationship between the diameter of the wire, the resistivity at 20.0°C, 0, the resistance at 20.0°C, R0, and the length L. (Do not substitute numerical values; use variables only.)
d =

(e) If L = 3.00 m, what is the diameter of the wire?
mm

To understand the behavior of the electric field at the surface of a conductor, and its relationship to surface charge on the conductor. a conductor is placed in an external electrostatic field. the external field is uniform before the conductor is placed within it. the conductor is completely isolated from any source of current or charge. part a: which of the following describes the electric field inside this conductor? it is in the same direction as the original external field.it is in the opposite direction from that of the original external field.it has a direction determined entirely by the charge on its surface.it is always zero. part b: the charge density inside the conductor is: 0non-zero; but uniformnon-zero; non-uniforminfinite part c: assume that at some point just outside the surface of the conductor, the electric field has magnitude e and is directed toward the surface of the conductor. what is the charge density η on the surface of the conductor at that point? express your answer in terms of e and ϵ0