Final answer:
The most appropriate exposure factors to control involuntary motion is 600 mA, 0.02 second, as lower exposure times minimize motion blurring in medical imaging. Electrical currents above 5 mA can stimulate muscular contractions. The "can't let go" effect occurs with higher currents causing involuntary muscle movement.
Step-by-step explanation:
The question is about identifying the set of exposure factors that would be most appropriate for controlling involuntary motion. In the context of radiology or medical imaging, reducing exposure time is crucial to minimize involuntary patient movement, such as muscle twitches. Option C (600 mA, 0.02 second) provides the shortest exposure time, which is ideal for reducing motion blurring and producing a better image quality. This is because higher milliamperage (mA) settings allow for shorter exposure times, which are effective in controlling involuntary motion.
Very small electrical currents usually pass through the body without being felt. However, higher currents can cause muscular contractions. The threshold for sensation is around 1 mA, while 5 mA is often considered the maximum non-harmful current. Currents between 10 to 20 mA can stimulate sustained muscular contractions, akin to nerve impulses, which can be strong enough to involuntarily close a person's hand around a conductive object. At even higher currents, more serious effects like the "can't let go" effect can occur, creating a safety hazard.