Answer:
f = 1.69*10^5 Hz
Explanation:
In order to calculate the frequency of the sinusoidal voltage, you use the following formula:
 (1)
          (1)
V_L: voltage = 12.0V
i: current  = 2.40mA = 2.40*10^-3 A
L: inductance = 4.70mH = 4.70*10^-3 H
f: frequency = ?
you solve the equation (1) for f and replace the values of the other parameters:
 
      
The frequency of the sinusoidal voltage is f
 
        
             
        
        
        
True, I'm not the best when it comes to science, but I'm pretty sure it's this
        
             
        
        
        
Answer:
It would mean less transpiration and the groundwater would start to make a landslide with no tree root to hold the earth in place
 
        
             
        
        
        
Well, since you only want direction, ignore the numbers. Use the right hand rule.
Current (pointer finger) points west (left). 
Magnetic field (middle finger) points south (towards you). 
Force (thumb) then points up (away from the earth)
        
             
        
        
        
<span><em>78% = nitrogen</em>
<em>21% = oxygen</em>
</span>
<em>%1  = noble gases</em>