Part 1. The figure below shows an electron shot with an initial velocity to left
ID: 2271735 • Letter: P
Question
Part 1. The figure below shows an electron shot with an initial velocity to left halfway between two oppositely charged plates. The voltage at this initial location is +50 V and the voltage at each plate is shown in the figure. The electron has initial velocity 3,010 km/s (please note km should be converted to m) to the left. The electron has insufficient energy to reach the 0 V plate, and thus changes direction at some point so that it moves to the right, what is the speed of the electron when it hits the +100 V plate (on the right)? Write your answer (in SI units) to three significant figures.
part. 2
If in Question 1, we replace the electron with a positron (same mass, but opposite charge q=+1.6x10-19 C), which of the following best describes the subsequent motion?
the positron will hit the 0 V plate with a speed larger than the initial speed
the positron will hit the 0 V plate with a speed equal to the initial speed
the positron will hit the 0 V plate with a speed less than the initial speed
the positron will not reach the 0 V plate, and hit the +100 V plate with a speed less than your answer to Question 1
the positron will not reach the 0 V plate, and hit the +100 V plate with a speed equal to your answer to Question 1
the positron will not reach the 0 V plate, and hit the +100 V plate with a speed greater than your answer to Question 1
the positron will hit the 0 V plate with a speed larger than the initial speed
the positron will hit the 0 V plate with a speed equal to the initial speed
the positron will hit the 0 V plate with a speed less than the initial speed
the positron will not reach the 0 V plate, and hit the +100 V plate with a speed less than your answer to Question 1
the positron will not reach the 0 V plate, and hit the +100 V plate with a speed equal to your answer to Question 1
the positron will not reach the 0 V plate, and hit the +100 V plate with a speed greater than your answer to Question 1
The figure below shows an electron shot with an initial velocity to left halfway between two oppositely charged plates. The voltage at this initial location is +50 V and the voltage at each plate is shown in the figure. The electron has initial velocity 3,010 km/s (please note km should be converted to m) to the left. The electron has insufficient energy to reach the 0 V plate, and thus changes direction at some point so that it moves to the right, what is the speed of the electron when it hits the +100 V plate (on the right)? Write your answer (in SI units) to three significant figures.Explanation / Answer
1) conservation of energy
1/2 mv^2 + q V = 1/2 mv^2 + q V
0.5*9.11E-31*3010E3^2 - 1.6E-19*50 =0.5*9.11E-31*v^2 - 1.6E-19*100
v=5.16E6 m/s
2) the positron will hit the 0v plate with a speed larger than the initial speed