Solving a Physics Problem: Electric Spark Distance Calculation

In summary, the conversation is about a physics problem involving finding the distance at which an electric spark would arise between a hand and a metal doorknob with a charge of Q=50nanoC. The person is asking if there is an equation to solve this and has tried googling for answers. The solution requires making assumptions and estimating the capacitance of the human body. The dielectric strength of air and the shape of the electrode (hand) are also important factors to consider.
  • #1
WilliamVeregg
1
0
I'm totally stuck on a physics problem. I've been looking through my notes and my book for the past hour and cannot find anything.

The question is

Find the distance at which an electric spark would arise between your hand and the metal doorknob if your hand carries a total charge of Q=50nanoC

Is there an equation to solve this? I've tried googling this also.
 
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  • #2
This has to be open ended and you need to make a number of assumptions.
The dielectric strength of air is approximately 3 kV/mm. In other words, a pd of 3kV will produce a 1mm spark.
You need to estimate the pd between your body (hand) and the door knob. (Take the door to be zero)
Can you find an estimate for the capacitance of the human body?
If so, one estimate would involve using this and the charge given to find V.
However, the shape of the electrode (your hand) also plays an important role.
 

Related to Solving a Physics Problem: Electric Spark Distance Calculation

1. How do I calculate the electric spark distance?

To calculate the electric spark distance, you will need to use the formula: d = (V^2 x t)/(2 x p x d), where d is the distance, V is the voltage, t is the time interval, p is the air pressure, and d is the distance between the electrodes. Make sure to use consistent units for all variables.

2. What factors affect the electric spark distance?

The electric spark distance can be affected by several factors, including voltage, air pressure, distance between the electrodes, and temperature. Additionally, the type of gas between the electrodes can also impact the spark distance, as some gases are more conductive than others.

3. How do I measure the time interval for the electric spark distance calculation?

The time interval for the electric spark distance calculation can be measured using a stopwatch or a timer. Make sure to start the timer as soon as the spark is generated and stop it when the spark reaches the other electrode.

4. Can the electric spark distance calculation be used for all types of gases?

No, the electric spark distance calculation is only applicable for gases that are considered to be perfect insulators, such as air. If the gas between the electrodes is a conductor, then the spark distance will be significantly shorter.

5. How accurate is the electric spark distance calculation?

The accuracy of the electric spark distance calculation depends on the accuracy of the measurements used (voltage, time, pressure, distance) and the assumptions made in the formula. In real-world situations, other factors such as humidity and impurities in the gas can also affect the accuracy of the calculation.

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