Questions tagged [electromagnetism]

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1answer
34 views

Transmitter receiver coil separation for Electromagnetic Terrain Conductivity Measurement

Why increasing transmitter-receiver coil separation in EM survey (EM31, also here) increases depth of penetration? Suppose there is a horizontal flat conductive layer underneath a flat resistive ...
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0answers
25 views

Electric permittivity of quartz

I'm performing an educational experiment on the piezoelectric effect in quartz, and it would be useful for me to know its electric permittivity. I've been told that the quartz sample that I have is ...
1
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0answers
18 views

Do living things have a magnetic field capable of any level of solar protection?

I understand how anything with an electrical current have a magnetic field including living things. Would a densely populated rain forest or jungle have enough combined magnetic field among the living ...
10
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1answer
333 views

Electricity in clouds and induced magnetism

This is well known to everyone that clouds carry electric charges and cumulonimbus clouds contain huge amount of electricity. It is also known from Maxwell's equations that moving particles induce ...
2
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1answer
236 views

Understanding pushbroom sensors

Does a push broom scanner scan a path perpendicular to the direction of satellite travel? I am confused because its detectors are arranged across track even though it scans along track.
9
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1answer
90 views

Does the Earth receive a net charge from the aurorae?

The sun radiates a lot of charged particles to the Earth. When the magnetic field of the Earth lines up to the poles, we get the beautiful polar lights. But are there as many negative charged as ...
5
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0answers
66 views

How does fog affect the conductivity/breakdown voltage of air?

Could the breakdown voltage of air significantly go down in very foggy weather (especially very salty fog from seawater)? Kind of a hypothetical question, but if anyone has something on this, I'd ...
4
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1answer
170 views

What is the meaning of integral of negative magnetic field (nT) over time?

I have a plot of the magnetic field (y-axis) over time (x-axis), one measure each hour (Dst - Disturbance Storm-Time). From time to time, there is a negative peak, which indicates a magnetic storm. ...
1
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2answers
96 views

What causes the earth to be a good grounding system?

When working with electricity, rubber shoes are recommended because they prevent current from running through your body. But I've read that usually the earth is more negative charged than positive. ...
4
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1answer
71 views

What causes aurorae?

I know that aurorae are caused by solar activity interacting with the Earth's magnetic field as charged particles are funneled down into the polar magnetic mirrors. On one hand, I know that as ...
6
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1answer
1k views

Is there a buildup of static electricity in a sandstorm?

In a sandstorm, is there a buildup of static electricity? If so, does that produce lightning strikes? Also if you were to be inside the storm what would the build of that level of static feel like?
13
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3answers
3k views

Is it possible for Earth to experience Polar Shift?

Many accounts claim that the Magnetic Field of the Earth has been seriously degrading for the past centuries and we are currently in the process of the so called Polar Shift. How likely would it be ...
6
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1answer
4k views

Does earth itself emit electromagnetic waves?

(.... and if so, of what frequency and amplitude)? This Skeptics.SE question about nonsense called 'geopathic stress' made me wonder if and how earth itself emits electromagnetic waves. We need ...
13
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1answer
2k views

How do you calculate the depth of penetration in a Schlumberger array?

In a resistivity survey, how do we calculate the depth of penetration for a Schlumberger array?
23
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1answer
2k views

What causes 'positive' lightning to be rarer, higher charged, and longer lasting than 'negative' lightning?

Why is 'positive' lightning rarer, brighter, higher charged, and longer lasting than 'negative' lightning? Are there any other unique characteristics to positive lightning that sets it apart from ...