Adisadvantage of some geophysical techniques based on magnetism is that their use in urban areas may be subject to distortion resulting from power lines and metals in the immediate vicinity. one method that can be used in such areas relies on soil moisture and the ground's resistance to electricity and is known

Resistivity Method

Explanation:

A disadvantage of some geophysical techniques based on magnetism is that their use in urban areas may be subject to distortion resulting from power lines and metals in the immediate vicinity. One method that can be used in such areas relies on soil moisture and the ground's resistance to electricity and is known as Resistivity.

It is usually carried out by injecting a small electrical current through the earth and measured a subtle  sub-surface change in resistance over a given area.

a solenoid is created by wrapping a l = 90 m long wire around a hollow tube of diameter d = 4.5 cm.   the wire diameter is d = 0.9 mm.   the solenoid wire is then connected to a power supply so that a current of i = 9 a flows through the wire.

randomized variablesl = 90 m

d = 4.5 cm

d = 0.9 mm

i = 9 a                                          

write an expression for the number of turns, n, in the solenoid. you do not need to take into account the diameter of the wire in this calculation.

calculate the number of turns, n, in the solenoid.

write an expression for the length of the solenoid (l2) in terms of the diameter of the hollow tube d.

calculate the length of the solenoid (l2)   in meters.

calculate the magnitude of the magnetic field at the center of the solenoid in teslas.

explanation:

0.93xc=0.93x3x10^8m/s

2.54cm is 1 inch

360seconds i 1 hr