# Can I trap mosquitos with Coulomb's force? [closed]

Can I fill a metallic conductor with a very large positive charge, attach it with a insulator to a wall, put it near a window under the sun (visible light and UV in order to cause it to expell electrons by photoelectric effect) and wait for mosquitos to fly near the metal and be injected with electrons? Would they become negatively charged enough to be attracted to the conductor permanently? Their mass is about 2.5 mg, maximum velocity is $0.7 \frac{m}{s}$ and their maximum kinetic energy is about 1.225 mJ. Their area is about 5$mm^2$.

## closed as off-topic by Kyle Kanos, stafusa, ZeroTheHero, Jon Custer, AccidentalFourierTransformSep 1 '18 at 2:22

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• If you can easily add electrons to a mosquito, what mechanism prevents the electrons from just hopping off again? – BowlOfRed Aug 30 '18 at 17:38
• I was thinking about a constant potential applied to the conductor in order to preserve the same total charge on it, while the flux of electrons is almost constant. Will a continuous flux of electrons on the mosquito work as a solution to the problem exposed by your question? – Costantino Aug 30 '18 at 17:47
• Unless there's some mechanism to keep charge on the mosquito, I don't know why the conductor wouldn't pull them off the mosquito as fast as anything else can put them on. It's not too hard to find the forces that would be present on a charged mosquito near some other charged object. It's much harder (and probably beyond this site) to understand how to establish and maintain such a charge on a free-flying mosquito. – BowlOfRed Aug 30 '18 at 17:53
• That would be a problem... While the solution comes, I found out that in order to generate a force that surpasses all the possible energy of the mosquito to escape, we need the quantity (qQ/r) to be greater than 7x10^(-14) C^2/m. q is supposed to be the charge on the mosquito and Q the one on the conductor; r the distance between the mosquito and the conductor where we want to extend the "capture" sphere. If we cover an entire room of 5m, it would be approximately qQ > 3.5*10^-13. Capacitance and voltage on the metal left to decide. – Costantino Aug 30 '18 at 18:59
• I think that by the time that you apply enough voltage to induce an electrical charge that might even come close to being significant that you'll just end up zapping the mosquitos with an electrical breakdown of the air through the mosquito, and of course that's already been done. – Samuel Weir Aug 30 '18 at 19:48

To create a sustainable electric field, you'll need to have the metal piece connected to a high voltage power supply. Otherwise, the charge will quickly dissipate.

If the field is strong enough, it might attract mosquitoes, even if they are not carrying any net charge, due to the electrostatically induced charge - which is similar to dust being attracted to charged objects. Also, I am not sure if the photoelectric effect due to UV in the sunlight will produce enough electrons to make a difference - will depend on the intensity of the sunlight and the type of metal.

A number of electrostatic mosquito traps have already been implemented - not sure how effective or wide spread they are. Some of them, like this, rely on an insect actually touching a plate, picking up a charge and then pulled to another plate. Some, like this, just include closely spaced positive and negative wires which trap mosquitoes, when the try to fly between the wires.