(2008? Yichang) induction cooker is a new type of cooker, as shown in the figure, which is a schematic diagram of induction cooker: there is a metal coil inside the cooker, when current passes through

(2008? Yichang) induction cooker is a new type of cooker, as shown in the figure, which is a schematic diagram of induction cooker: there is a metal coil inside the cooker, when current passes through it. (1) Because the induction cooker uses the heat generated by the pot itself to heat food, there is no heat transfer process from the stove to the pot, and the heat loss is less, so the thermal efficiency of the induction cooker is higher;

(2) Electric energy consumed by heating water:

w = Pt = 2000 w× 175s = 3.5× 105j，

Heat absorbed by water:

Q suction = cm water △t

=4.2× 103J/(kg？ ℃)× 1kg×( 100℃-25℃)

=3. 15× 105J，

Thermal efficiency of induction cooker:

η=Q absorption w×100% = 3.15×105j3.5×105jx100% = 90%.

Answer: (1) Compared with ordinary electric furnaces, induction cookers have higher thermal efficiency;

(2) The power consumption is 3.5× 105J, and the thermal efficiency of the induction cooker is 90%.