Read the short text and answer the question:
A kettle
As shown in figure a, the electric kettle works by connecting the power supply, increasing water temperature to 100 °c, deforming the two-metal tablets to drive the steam switch, and automatically cutting off the power of the kettle after the water has been burned (the next time the boiling water has to be shut down). If the steam switch fails, the water in the pot will be boiled, the temperature of the heat component will rise dramatically, and there will be a double-metal plate switch at the base of the radiator, which will cause the heat transfer to rise sharply and break the power source
Figure b shows the principle of double-metal switches. A is a double-metal piece, made of two layers of different metal adhesives, which expand differently in heat. In the absence of electricity or below the predicted temperature, the contact points on the double metal plate a and the silent plate b are connected, the heat drive works, when the temperature reaches the expected temperature, the double metal piece bends to the left (the higher the temperature, the greater the degree of bending) and the circuit is cut off. C is a modulated spin button, which adjusts the strength of the double metal piece in contact with the silent piece elasticity.
Now many of the high-end electric hotpots use ptc heating components. Figure c is a temperature-changed image of ptc material. Using ptc heating components prevents fire hazards from dry burning. The temperature control function of the ptc heating element is absolutely reliable. It is controlled by ptc resistance changes, not by contact control
(1) to ensure safety, the water kettle vapour switch shall be connected to the bimetal plate switch (serial/joint)
(2) if the power is not provided by a three-line plug, hand-to-hand with the metal shell of the kettle (sure/specified/probably)
(3) with regard to the two-metal tablets in the tma canteen, the following statement is correct:
A. Metallic layera expands faster than b when bimetal chips are heated
B. Aligning spin button c to increase the temperature of the still b to the left and split double metal pieces
C. Steam switches and double metal plate switches at the base of the heater are always disconnected simultaneously
D. Double-metal chips are frequently out of power, easily burned together and the water must have dried up
(4) the final temperature range of the heater when the ptc canteen is electrified shall be east of
A. T0-t1 b. T1-t2 c. T2-t3 d. T3-t4
(5) the ptc heat material power changes over time after the ptc canteen is
