Mechanical thermostats for home heating, and flasher units for car turn-signals (and Christmas tree lights!) often use this principle: Two strips, copper and iron, are bonded together, side by side. They share the same elastic properties (e.g., Young?s modulus), and the same length l, and diameter d. They don't have the same linear thermal-expansion coefficient, though ? if we heat them both to a higher temperature, one expands more than the other, and they bend. If the change in temperature is delta T and the linear thermal-expansion coefficients (alpha Fe) and (alpha Cu) , find the angle of deflection.

Aditi Chauhan , 11 Years ago

Grade 10