If the original technique is 100 mA at 1 second, what milliamperage should be used to reduce the exposure time to 0.25 seconds while maintaining the same mAs?

To maintain the same milliamperage-seconds (mAs) while reducing the exposure time, it is essential to understand the relationship between milliamperage (mA), exposure time (in seconds), and mAs. The formula for calculating mAs is:

mAs = mA × time (in seconds)

In this scenario, the original technique is set at 100 mA for 1 second, which gives us:

mAs = 100 mA × 1 s = 100 mAs.

Now, if the exposure time is reduced to 0.25 seconds, the mA must be adjusted accordingly to maintain the same mAs of 100. To find the new mA value, we rearrange the mAs formula to solve for mA:

mA = mAs / time

Substituting the values we have:

mA = 100 mAs / 0.25 s = 400 mA.

This calculation confirms that if the exposure time is shortened, the milliamperage must be increased to compensate, and in this case, the correct milliamperage to achieve the same exposure is 400 mA.