Physics Help: Calculating Electric Shock Voltage/Current

In summary, the conversation is about the effects of electric shock on the human body and calculating the minimum voltage and resulting current that can be felt by a person with dry or wet skin. The formula I=V/R is used to find the current, and it is important to pay attention to units when using this formula. The question itself may be inaccurate and should not be used for handling electricity.
  • #1
Palmtree Panic
7
0
Physics help, urgent!

Homework Statement




The damage caused by electric shock depends
on the current fowing through the body;
1 mA can be felt and 5 mA is painful. Above
15 mA, a person loses muscle control, and 70
mA can be fatal. A person with dry skin has a
resistance from one arm to the other of about
70000 ohms *. When skin is wet, the resistance
drops to about 5000 ohms .
a.)What is the minimum voltage placed across
the arms that would produce a current that
could be felt by a person with dry skin? An-
swer in units of V.
b.) Using the same electric potential as in Part 1,
what would be the current if the person had
wet skin? Answer in units of mA.

Homework Equations



I=V/R

The Attempt at a Solution



I got part a right. It's 70 V.
For b.) I did 5000/70. but it wasn't right. Can someone help?
 
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  • #2
upside down?

Compare what you did to the formula.
 
  • #3
answer why you tried 5000 / 70 ?

what does "Part 1" refer to?
 
  • #4
whoops

I should have done 70/5000 because V=70 and R=5000.
I got .014 but it is still wrong.

Part 1 means part a.
 
  • #5
Make sure you follow directions and give the answer in the correct units.
 
  • #6
...

I got .014 mA. Can someone explain what I'm doing wrong?
 
  • #7
Check your units. Volts/Ohms = Amps.
 
  • #8
WARNING!
I know this has nothing to do with the question, but the question is quite simply dangerously wrong. Wet or broken skin is closer to 1000 Ohms and a wound can be lower. No one should handle electricity based on the information in the question. Source: NIOSH
 
  • #9


hey can u play explain to me how u got part a?
 
  • #10


victorlee2 said:
hey can u play explain to me how u got part a?
Use Ohm's law, the formula given in post #1.
 

1. How do I calculate the voltage of an electric shock?

To calculate the voltage of an electric shock, you can use the formula V= IR, where V represents voltage, I represents current, and R represents resistance. First, measure the current using an ammeter and the resistance using an ohmmeter. Then, plug these values into the formula to calculate the voltage.

2. What is the difference between voltage and current?

Voltage is the measure of the potential energy difference between two points in an electric circuit, while current is the flow of electric charge through a conductor. In other words, voltage is the driving force behind the flow of current.

3. How much voltage can the human body withstand?

The amount of voltage that the human body can withstand varies depending on factors such as the path of the current, duration of exposure, and individual health. However, it is generally accepted that any voltage above 50 volts can be dangerous and potentially fatal.

4. How does the body react to electric shock?

When the body experiences an electric shock, the current can disrupt the normal flow of electricity in the body and interfere with the nervous system. This can cause muscle contractions, burns, and potentially fatal disruptions in heart rhythm.

5. What safety precautions should be taken when working with electricity?

When working with electricity, it is important to always follow safety precautions to avoid electric shocks. This includes wearing protective gear such as rubber gloves and shoes, using insulated tools, and turning off the power source before working on circuits. It is also important to never touch a live wire or work on electrical equipment in wet or damp conditions.

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