Current flow of how many milliamps can be painful, cause muscular paralysis, and breathing difficulties?

Current flow of how many milliamps can be painful, cause muscular paralysis, and breathing difficulties?

• A. 5 mA
• B. 10 mA
• C. 15 mA
• D. 20 mA

Answer: (B)

The big idea here is how body response to electrical current ramps up with increasing magnitude. At very small currents you might feel a slight tingling, but as current climbs into the few-milliamp range the shock becomes painful and muscles begin to react strongly. Around 10 mA, those muscle contractions are significant enough that you can have trouble trying to let go of the source, and the muscles involved in breathing can be affected, making breathing more difficult. This combination—pain, strong muscular response, and potential breathing difficulty—fits best with a current near 10 mA. Higher currents increase the risk even more, but 10 mA is the threshold where those specific effects start to appear together.

The big idea here is how body response to electrical current ramps up with increasing magnitude. At very small currents you might feel a slight tingling, but as current climbs into the few-milliamp range the shock becomes painful and muscles begin to react strongly. Around 10 mA, those muscle contractions are significant enough that you can have trouble trying to let go of the source, and the muscles involved in breathing can be affected, making breathing more difficult. This combination—pain, strong muscular response, and potential breathing difficulty—fits best with a current near 10 mA. Higher currents increase the risk even more, but 10 mA is the threshold where those specific effects start to appear together.