There are several important applica tions of the principle of expansion of solids due to heating the solid. One appli- cation is
found in the type of there mometer called a thermocouple. If strip of metal is heated, it will expand. Some metals will expand more than others for the same amount of heat, each metal has definite expansion for a specific amount of heat. Therefore, if two different metal strips are bound together and the single strip of metals will tend to assume curved position because of the greater expansion of one metal as compared to the other. This curvature can make con tact with an electrical circuit, starting an electric motor or operating some other electromechanical device. In the home a thermocouple stops or starts the oil burn- er in accordance with the room tempera- ture. The temperature of a gasoline engine can be measured with a device similar to a thermocouple. 1.) A thermocouple
A.) creates heat
B.) creates electricity
C.) makes or breaks contact
D.) cannot work automatically
2.) the reader can infer that a thermocouple will not work when
A.) the 2 metals are very long
B.) both metals are 4 inches think and 1 inch long
C.) one metal is thicker than the other
D.) the 2 metals are is different lengths
