<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.
</u>
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.
<em>hope this helps PLEASE MARK AS BRAINLIEST:)</em>
Step by step solution :
standard deviation is given by :

where,
is standard deviation
is mean of given data
n is number of observations
From the above data, 
Now, if
, then 
If
, then 
if
, then 
If
, then 
If
, then 
so, 



No, Joe's value does not agree with the accepted value of 25.9 seconds. This shows a lots of errors.
Thaattttttt would be mass vs volume im in science now. hope it helps
Answer:
A lot of the earth oxygen comes from the ocean around 50%-80%
Explanation: