The flash unit on a camera operates by storing charge on a capacitor and releasing it suddenly when the flash is set off. The following data describe the charge Q remaining on the capacitor measured in microcoulombs, C at time t measured in seconds. t 0.00 0.02 0.04 0.06 0.08 0.10 Q 100.00 81.87 67.03 54.88 44.93 36.76 a Use a graphing calculator or computer to find an exponential model for the charge. b The derivative Q(t) represents the electric current measured in microamperes A flowing from he capacitor to the flash bulb. Use part a to estimate the current when t=0.04s. Compare with the result of Example 1.4.2.