Instead of thinking about one field changing in response to the change of the other, it is more correct to say that. whenever the magnetic field is changing, so is the electric field, and vice versa.The way these fields change is governed by Maxwell's equations.This way, we do not arrive at the confusion OP has.nstead of thinking about one field changing in response to the change of the other, it is more correct to say that. whenever the magnetic field is changing, so is the electric field, and vice versa.
Gross profit = net sales â cost of goods sold. Gross profit percentage = [(net sales â cost of goods sold)/net sales] Ã 100%.
Express this ratio as a percentage. Gross profit margins are usually written as a percentage. Once you have the ratio for gross profit / total revenue, simply multiply the resulting decimal by 100 to get a percent value. 1  Example: For the sporting goods shop, the gross profit margin is: 55,000/100,000 = .55 Ã 100 = 55% .ivide gross profit by total revenue. Gross profit margin (sometimes just called gross margin) is different that gross profit. Gross profit margin is the ratio of your gross profit to your total revenue.