Answer:
magnetic field will allow the electron to go through 2 x
T k
Explanation:
Given data in question
velocity = 5.0 ×
electric filed = 
To find out
what magnetic field will allow the electron to go through, undeflected
solution
we know if electron move without deflection i.e. net force is zero on electron and we can say both electric and magnetic force equal in magnitude and opposite in directions
so we can also say
F(net) = Fe + Fb i.e. = 0
q V B + q E = 0
q will be cancel out
+ 5e + 7i × B = 0
B = 2 x
T k
Answer:
I think its A
Explanation:
if its every 3 seconds wouldnt it be 3.0 Hz
1) In the reference frame of one electron: 0.38c
To find the relative velocity of one electron with respect to the other, we must use the following formula:

where
u is the velocity of one electron
v is the velocity of the second electron
c is the speed of light
In this problem:
u = 0.2c
v = -0.2c (since the second electron is moving towards the first one, so in the opposite direction)
Substituting, we find:

2) In the reference frame of the laboratory: -0.2c and +0.2c
In this case, there is no calculation to be done. In fact, we are already given the speed of the two electrons; we are also told that they travel in opposite direction, so their velocities are
+0.2c
-0.2c
Answer:
For number 4: A vector pointing to the right with a magnitude of 2.0
Explanation:
Very simple- just subtract 6-2
I am not sure how to do #2- sorry!

Actually Welcome to the Concept of the Optical Devices.
Now basically here the devices that can spread light over apart are the CONCAVE LENS and Convex mirror.
so the Answer is
C. B and D