Answer:
A battery produces _DC_ current, which is current that flows in only one direction.
Answer:
Magnetic field, 
Explanation:
It is given that,
Number of turns, N = 320
Radius of the coil, r = 6 cm = 0.06 m
The distance from the center of one coil to the electron beam is 3 cm, x = 3 cm = 0.03 m
Current flowing through the coils, I = 0.5 A
We need to find the magnitude of the magnetic field at a location on the axis of the coils, midway between the coils. The magnetic field midway between the coils is given by :


B = 0.00239 T
or

So, the magnitude of the magnetic field at a location on the axis of the coils, midway between the coils is
. Hence, this is the required solution.
Answer:
<h2>
<em>True</em></h2>
Forests helps in binding the soil together. Thus, prevent soil from erosion.
Explanation:
It is given that, a long, straight wire is surrounded by a hollow metal cylinder whose axis coincides with that of the wire.
The charge per unit length of the wire is
and the net charge per unit length is
.
We know that there exist zero electric field inside the metal cylinder.
(a) Using Gauss's law to find the charge per unit length on the inner and outer surfaces of the cylinder. Let
are the charge per unit length on the inner and outer surfaces of the cylinder.
For inner surface,



For outer surface,



(b) Let E is the electric field outside the cylinder, a distance r from the axis. It is given by :


Hence, this is the required solution.