Answer:
Magnetic field, 
Explanation:
Given that,
Velocity of electron, 
It enters a region of space where perpendicular electric and a magnetic fields are present.
Magnitude of electric field, 
We need to find the magnetic field will allow the electron to go through the region without being deflected.
Magnetic force on the electron,
.......(1)
Electric force on the electron, F = q E........(2)
From equation (1) and (2) we get:



B = 0.0002 T
or

Hence, this is the required solution.
Static electricity travels to the door knob because of the friction caused by the feet on the carpet. the friction traveled through the person, to their hand, and to the door knob because it is the best conductor.
An ice cube would transfer heat to another object whose temperature
is lower than zero°C (32°F).
A block of "dry ice" is sitting there at a temperature of -78°C (-109°F).
An ice cube helps to melt dry ice nice and fast.
If you could find a block of solid nitrogen, its temperature would be
63K (-210°C, -346°F). An ice cube would transfer heat to that baby
so fast that it would instantly boil.
Speed is equal to distance traveled divided by the time. So it's 3.5 m/s
Reflecting telescope. Reflecting telescopes tend to have larger objective (due to the use of mirrors, mirrors are a lot cheaper than lenses) and have the ability to collect more light, while refracting telescopes are limited to objective lenses with smaller diameters due to their structural limitations (chromatic abbreviation, for example). Therefore, reflecting telescopes should be better at viewing faint distant stars