1. The intensity of sunlight (at midday) is about 1 kW/m2.
2. If solar panels are 20% efficient in making electricity, how large an area of solar panels to produce 5 kW of electrical power?
3. How many hours of sunshine with this set up to collect enough energy to accelerate the sedan as in 2c. above? Assume the electric sedan is 100% efficient, same weight.
4. If is dangerous to look at the sun during an eclipse, in part because the pupil is much more dilated. If the diameter of the pupil increases by a factor of 3 (triples), how much more energy enters the eye in each second of looking than if the pupil were not dialated? [You might answer this without Excel.]
5. How intense is full sunshine compared with a laser that shines 1 mW into a circular bean 3 mm in diameter. [First calculate area of beam, then divide 10-3 W by that to get intensity of laser. Take the ratio of the solar to laser intensities.]