Assume a stellar atmosphere of pure helium. (a) find i at t=15,000k. assume ni the electron pressure in the atmosphere is pe 20 n /m2. calculate how this would change for t 5,000k and t 25,000 k. helium has two electrons and so can be doubly ionized, he iii. (b) what is nat t-15,00ok. calculate how this would change for t = 5,000k and t 25,000 k. (c) how does l compare to as the temperature changes? describe why this occurs ni

Cyclotrons are widely used in nuclear medicine for producing short-lived radioactive isotopes. these cyclotrons typically accelerate h- (the hydride ion, which has one proton and two electrons) to an energy of 5 mev to 20 mev. this ion has a mass very close to that of a proton because the electron mass is negligible—about 1 2000 of the proton’s mass. a typical magnetic field in such cyclotrons is 1.9 t. (a) what is the speed of a 5.0-mev h-? (b) if the h- has energy 5.0 mev and b = 1.9 t, what is the radius of this ion’s circular orbit?