[填空题]
A low-power laser use3hmeh,rtgu, lr:kj /7d in a+(nh65, dmxxu sv5euw physics lab might have a power of $0.50 \, \text{mW}$ and a beam diameter of $3.0 \, \text{mm}$. Calculate
(a) the average light intensity of the laser beam, I = $W/m^2$
(b) compare it to the intensity of a lightbulb producing $40$-W light viewed from $2.0 \, \text{m}$.I = $W/m^2$ The laser beam is more intense by a factor of
