10-49 An electron in an oscilloscope beam
travels
between the deflecting plates with an initial velocity of 2.0X107
m/s parallel to the plates, which lie in a horizontal plane. The
electric
field is 2.2X104 N/C downward, and the plates have a length
of 4.0 cm. When the electron leaves the plates, (a) how far has it
dropped
or risen? (Specify which.) (b) what is its velocity (magnitude and
direction)?
[Ans. (a) risen 7.7X10-3 m (b) 2.1X107
m/s at 21° above horizontal]
As always we need a good drawing of the physical
situation. Which is correct - remember the particle is an electron?
