The rest energy of an electron is 0.511 MeV = 8.2 x10-14 J. A positron is an electron with positive charge and the same rest energy. Within what time interval can we create and destroy an electron-positron pair without worrying about the conservation of energy? h = 6.626 × 10-34 J s.
In a typical color television tube, the electrons are accelerated through a potential difference of 25,000 Volts. What speed do the electrons have when they strike the screen? (qe = 1.6 x10-19 C, me = 9.1 x10-31 kg)
What is the minimum (non-zero) thickness of a soap film having index of refraction 1.46, with air on both sides, that transmits virtually 100% of 500 nm light incident along the normal?
a. 345 nm.
b. 86 nm.
c. Any thickness transmits 100%.
d. 172 nm.
What happens to a light wave when it is reflected off the surface of a material with a higher index of refraction?
a. It reflects with its phase shifted by π.
b. It reflects with its phase shifted by π/2.
c. The phase shift is proportional to the angle of reflection.
Assume that a uniform magnetic field is directed into this page. If an electron is released with an initial velocity directed from the left edge to the right edge of the page, which of the following describes the direction of the resultant force acting on the electron?
I think it would come...