Amperage is the measure of:

• A. the penetrating capacity of the x-rays
• B. the amount of electrons in motion
• C. the current flow
• D. the distance from the source of electrons

Answer: (C)

Amperage measures the current flow—the rate at which electrons pass a point in a circuit. In an X-ray tube, increasing the tube current (mA) means more electrons reach the target each second, producing more X-ray photons and a higher exposure. This is about how many electrons are moving per unit time, not how energetic the photons are (that’s controlled by the voltage, or kVp), nor the total number of electrons present at one instant. Distance from the source affects intensity through the inverse-square relationship, not amperage itself. So the best description is that amperage is the current flow.