PHYSICS 7C Midterm: physics7C-fa2000-mt2-Lee-exam
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You can write on both sides of the page. 16 r2 where psun is the radiant power output of the sun. (25 pts: evaluate the temperature numerically. Use tsun = 5500k, rsun = 7 x 108 m, What is the momentum p of the electron? (15 pts) A stream of such electrons diffracts through an aperture. What could be used to produce such apertures (a decent guess is enough)? (10 pts) Do the electrons have relativisitic velocities, i. e. is the (gamma) factor appreciably different from 1? (15 pts) A pole vaulter is running with a pole at v = sqrt(3)/2 c. her pole has a proper length of l. she runs into a barn with proper length l/2 with doors on the front and back. From the farmer"s perspective can he close the barn doors at the same time? (10 pts) What is the interpretation of the sign of the expression? (15 pts)
