A patient is moving in a magnetic field for 2 seconds and experiences a magnetic spatial gradient of 200G/cm. What dB/dt are they experiencing?

To determine the correct answer, let's first understand what the magnetic spatial gradient and the time duration imply about the rate of change of the magnetic field intensity that the patient experiences.

The magnetic spatial gradient is measured in Gauss per centimeter (G/cm), and in this case, the gradient is given as 200 G/cm. To convert the gradient to Tesla, we note that 1 Tesla (T) equals 10,000 Gauss (G). Therefore, 200 G/cm translates to 0.02 T/cm (since 200 G divided by 10,000 gives 0.02 T).

Next, to find the dB/dt, or the rate of change of magnetic field per second, we need to relate it to the distance over which the field is changing. The given gradient implies that the magnetic field will change by 200 G over a distance of 1 cm. If the patient is in this gradient for 2 seconds, we consider that the experienced rate of change (dB/dt) can be estimated by the spatial gradient over time.

Since the magnetic field is changing over the time period while keeping the distance constant, the formula we usually use to calculate dB/dt in terms of the gradient is: