<u>Metal detectors work by transmitting an electromagnetic field from the search coil into the ground. Any metal objects (targets) within the electromagnetic field will become energised and retransmit an electromagnetic field of their own. The detector’s search coil receives the retransmitted field and alerts the user by producing a target response. metal detectors are capable of discriminating between different target types and can be set to ignore unwanted targets.
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1. Search Coil
The detector’s search coil transmits the electromagnetic field into the ground and receives the return electromagnetic field from a target.
2. Transmit Electromagnetic Field (visual representation only - blue)
The transmit electromagnetic field energises targets to enable them to be detected.
3. Target
A target is any metal object that can be detected by a metal detector. In this example, the detected target is treasure, which is a good (accepted) target.
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<span>The sun, lightning, the ionosphere, fluorescent light bulb, stars, fire, tv, and solar winds. I don't know your other options but these are my examples.</span>
Explanation:
At the top of the tree, the velocity of the pebble is purely horizontal so we can calculate it as
To minimize neutron leakage from a reactor, the ratio of the surface area to the volume should be a minimum. For a given volume V the ratio of the sphere will be 
.
We know that the surface area and volume of the sphere is given by:
Therefore, the ratio between the surface area and the volume for the sphere will be:
Equating the volume to the constant c, we will find the value of 
.
Substituting the value of r in the ration between surface area and volume, we get:
Calculating the constants, we get:
Hence, the ration between surface area and volume is
To learn more about surface area and volume of sphere, refer to:
brainly.com/question/4387241
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