Final answer:
As little as 100 mA (0.1 A) of electrical current can cause cardiac arrest. Currents of 10 to 20 mA can cause involuntary muscular contractions, and even lower currents can be dangerous for microshock-sensitive patients, highlighting the need for stringent safety precautions.
Step-by-step explanation:
Electricity can indeed pose unseen hazards in a laboratory setting, where as little as 100 mA (0.1 A) of electrical current can potentially cause cardiac arrest. Currents below 5 mA are generally not harmful and may go unfelt by the body. When currents reach the range of 10 to 20 mA, they can induce sustained muscular contractions. Currents higher than this, especially in the range of 60 to 100 mA, can result in more severe consequences, like ventricular fibrillation, which can lead to cardiac arrest.
It's important to note that for microshock-sensitive patients, even extremely low currents, as low as 0.1 mA, can cause ventricular fibrillation. This underscores the need for strict electrical safety precautions, especially in environments like hospitals where such sensitive individuals may be present.