If you touch the two terminals of a power supply with your two fingertips on opp
ID: 777335 • Letter: I
Question
If you touch the two terminals of a power supply with your two fingertips on opposite hands, the potential difference will produce a current through your torso. The maximum safe current is approximately 5 mA.
(a) If your hands are completely dry, the resistance of your body from fingertip to fingertip is approximately 455k. If you accidentally touch both terminals of your 115 V household electricity supply with dry fingers, what current will flow, and will you receive a dangerous shock?
__________ mA (dangerous or harmless shock)
(b If your hands are moist, your resistance drops to approximately 1.9 k. If you accidentally touch both terminals of your 115 V household supply with moist fingers, what current will flow, and will you receive a dangerous shock?
___________ mA (dangerous or harmless shock)
Explanation / Answer
from ohms law
i=v/r
1st case
i=115/455000
=0.25 mA
so will not recieve dangerous shock
2nd csae
i=115/1900
=0.06 A
=60.52 mA
will recieve dangerous shock