The density is determined on the steepness of the slope. The greater the density is bases upon the steepest slope. To conclude, I'd say Line A has the steepest slope therefore has the greatest density.
To protect a material from the influence of an external magnetic field, the material should be kept in soft iron ring.
So the correct answer is A.
Hope this helps,
Davinia.
Answer:

Explanation:
Given


Required
Determine the distance at which the lighting struck
First, we need to determine the speed at which the lighting struck because the peed of sound varies with temperature.
At about 28C, the speed of sound is 346m/s
So, we have the following:


Distance is calculated as thus:



Divide by 1000 to get distance equivalent in kilometers


---- Approximated