Briefly explain why sunspots are cooler than surrounding regions of the Sun and why they look dark in photos
What will be an ideal response?
They are cooler because their strong magnetic fields suppress convection and prevent hotter material from flowing into them. Because they are cooler, they emit less thermal radiation per unit area and therefore look dark in contrast to brighter surrounding regions.
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A horizontally-projected beam of protons travelling at 55 km/s travels between two parallel plates separated by 7.4 cm, and 12 cm long, between which there is an electric field of 7.2 V/m upward. If the beam enters the region at a height of 3.7 cm above the lower plate, at what height above the lower plate is the beam when it exits? The proton mass is 
A. 4.4 cm B. 3.0 cm C. 5.1 cm D. 2.3 cm
Throughout your website, vary the use of navigation menus, bars, and tabs to provide interest and contrast to visitors.
Answer the following statement true (T) or false (F)
In a 400-m relay race the anchorman (the person who runs the last 100 m) for the Trojans can run 100 m in 9.8 s. His rival, the anchorman for the Bruins, can cover 100 m in 10.1 s
What is the largest lead the Bruin runner can have when the Trojan runner starts the final leg of the race, in order for the Trojan runner not to lose the race?
The "half-life" of a large collection of radioactive nuclei is
A. larger for heavy nuclei than for lighter nuclei. B. the number of nuclei that remain after 1 second. C. the time for half of the collection to decay. D. the number of nuclei that decay in 1 second.