A photocell is any of a wide range of sensors that react based on the presence of light or electromagnetic energy. They can be found in many different forms, from solar panels that use light to generate electricity, to photoresistors, which shift in resistance based on how much light is present.
Bond prices and yields are like a seesaw: when bond yields go up, prices go down, and when bond yields go down, prices go up. In other words, a move in the 10-year Treasury yield from 2.2% to 2.6% indicates negative market conditions, while a move from 2.6% to 2.2% indicates positive market performance.
What is a 'Yield Spread' A yield spread is the difference between yields on differing debt instruments of varying maturities, credit ratings and risk, calculated by deducting the yield of one instrument from another. For example, if the five-year Treasury bond is at 5% and the 30-year Treasury bond is at 6