According to Faraday's Law a change in magnetic flux will induce emf as according to the formula emf = (ceebs latexing formula). As current does not reach maximum instantaneously, there is a brief building up period. According to the relationship B = kI/d, current is proportional to B, and hence as the current builds up (therefore changes) similarly there is a change in magnetic flux inducing emf on the phone. As the build up interval is very small, the change in magnetic flux would be very high and hence the repeated emf induced on the phone would be very high, which could lead to damage of the phone's internal components. This will occur both when the charge is turning on and when it is turning off, meaning that the emf is being repeatedly applied to the phone, potentially causing damage to the internal components.