Electricity and the shortest path

In summary, people die when a radio falls into the tub they are bathing in because the current passes through the water and the person.
  • #1
ShawnD
Science Advisor
718
2
Why do people die when a radio falls into the tub they are bathing in?
The wires only have a voltage relative to each other. Red has voltage relative to black, but not the water or the person. Black has voltage relative to red, but not the water or the person. Electricity always follows the path of least resistance, so shouldn't the electricity go straight between red and black instead of going through all the water and the person?
 
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  • #2
Electricity follows all paths. More current flows through the lower resistances, but some flows through all of it. Additionally, the black is just ground... the same as the pipes and the tub. To make it worse, you short circuit the plug, so you're pulling between 15 and 20 amps... usually 20 if it's a bathroom fixture that isn't GFCI or AFCI protected.
 
  • #3
When you connect two resistors of different resistance in parellel, will current only flow throught the resistor with lower resistance?

I is proportional to 1/R, and the resistance of "all the water and the person" is simply not high enough to make the current neglible. And I guess the reason they die is that they don't have time to climb out of the bath tub before the electric shock becomes critical, because as far as I know you lose most control over your muscles in these situations and they contract themselves. That's why when you touch a lamp, for example, to see if it's dangerous, you should touch it with the back of your hand rather than grab it. But I may well be wrong. :wink:
 
  • #4
ShawnD said:
Why do people die when a radio falls into the tub they are bathing in?
They don't. It's a myth created by Hollywood. It's similar to the myth that you can electrocute someone with a car battery.
 
  • #5
krab said:
They don't. It's a myth created by Hollywood. It's similar to the myth that you can electrocute someone with a car battery.

What? You can't be serious.
 
  • #6
What would make you doubt Krab? He's always been right before.
Everybody knows you can't shock somebody with a car battery, but the radio in the bathtub thing is somewhat believable.
 
  • #7
ShawnD said:
What would make you doubt Krab? He's always been right before.
Everybody knows you can't shock somebody with a car battery, but the radio in the bathtub thing is somewhat believable.

The car battery situation I understand. My gripe is with the radio, like you suggested.
My wife has a hair dryer in our bathroom which has a "Do Not Remove" tage on it. The tag has a drawing of a bathtub and a hair dryer above it and a big red X over the entire pic. The text on the tag says :To Reduce Risk of Electrocution Do Not Use Near Water"
 
  • #8
Kill you or not, I doubt it's in your best interest to throw any electric device into your bath tub.
 
  • #9
Throwing a radio into the tub will probably trip the breaker before it has a chance to do any real damage.
If the break doesn't work properly, your house will probably start on fire :biggrin:
 
  • #10
You can die if you have 20 amps go through you. But in the bathtub, most of the current will pass through the water (R~L/A, or think of it as the potential gradient across your body being small compared to some of the water near the electrical leads). So, even if you short the supply without tripping a breaker or fuse, you're only going to get badly zapped, at worst.

Note that this is very different from sticking metal wires into a the sockets of a power outlet - though if you hold both wires in the same hand, like chopsticks, you may only end up with a toasted hand.

Please don't try any of these things cause they are all extremely dangerous, and most are exceptionally stupid.
 
  • #11
I actually stuck things in the wall before when I was like 5. Knife in either side then touch em; youch! Hopefully it didn't fug my heart.
 
  • #12
Yeah, I tripped the circuits 3 times within about a year when I was little, nearly electrocuting myself, and understanding better than most at an early age how electricity works.
 
  • #13
OK, let's do an experiment to find out.
First, let's get our hands on that ******* who beheaded Daniel Berg in Iraq. (BTW, I saw the ENTIRE video of the execution... most disturbing)
Next, let's give that ******* a bath since he likely hasn't had one since he was born.
Then, let's put in some pretty pink bubble soap just to piss him off.
Now, let's throw in a live connected radio, hair dryer AND T.V. and see what happens.
Of course, as good scientists, we will want to repeat the experiment several times.
 
  • #14
In that experiment, if you used big wires and no fuses/breakers, the water would probably boil and he would die from the heat.
 
  • #15
krab said:
They don't. It's a myth created by Hollywood. It's similar to the myth that you can electrocute someone with a car battery.

It is far from a myth created by anyone.

The breaker wil not trip (unless it is a groung fault breaker those with reset on it) and you are not only die but you will die cook.
 

1. What is the concept of shortest path in electricity?

The concept of shortest path in electricity refers to the path that has the lowest resistance and allows for the most efficient flow of electric current. It is the path that has the least amount of impediments, such as resistors or other components, that can impede the flow of electricity.

2. How does electricity flow through the shortest path?

Electricity flows through the shortest path by following the path of least resistance. This means that it will take the path that offers the lowest resistance, allowing for the most efficient flow of current. This can be seen in Kirchhoff's laws, which state that the sum of current entering a node must equal the sum of current leaving the node.

3. Why is it important to find the shortest path in electrical circuits?

Finding the shortest path in electrical circuits is important because it allows for the most efficient use of energy. By minimizing the resistance in the circuit, the amount of energy lost as heat is reduced, resulting in a more efficient system. It also helps to prevent damage to components and ensures that the circuit functions properly.

4. How is the shortest path determined in electrical circuits?

The shortest path in electrical circuits can be determined by using Ohm's Law, which states that the current in a circuit is equal to the voltage divided by the resistance. By calculating the resistance of each path in the circuit, the path with the lowest resistance can be identified as the shortest path.

5. Can the shortest path change in an electrical circuit?

Yes, the shortest path in an electrical circuit can change depending on the components and conditions present in the circuit. As components are added or removed, the resistance of different paths may change, resulting in a new shortest path. Additionally, changes in temperature or other external factors can also impact the resistance of a circuit, leading to a change in the shortest path.

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