Refractive index of seawater and a diver transmitting RF for 100 meters

AI Thread Summary
To calculate the time it takes for a radio signal sent by a diver 100 meters below the surface to reach someone on the surface, the refractive index of seawater must be determined. The refractive index can be influenced by factors such as salinity and temperature, with seawater having a higher refractive index than air. Additionally, the attenuation of radio frequency signals in seawater is significant, especially at higher frequencies, which is why submarines use extremely low frequency (ELF) signals for communication. Understanding these factors is crucial for solving the problem. Researching the refractive index and RF signal behavior in seawater will provide the necessary insights for accurate calculations.
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Homework Statement
We received the following riddle:
a diver 100m below surface, in 32% salinity and 2 degrees Celsius sends a radio signal. How long will it take someone on the surface to receive the signal?
Relevant Equations
v*t=d
v=c/n
I thought I maybe need to find a way to calculate the refractive index (n) and using that calculating the velocity and then the time but I haven't managed to figure out how to get the refractive index? Would love your help.
 
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xphrnzrjh said:
Homework Statement: We received the following riddle:
a diver 100m below surface, in 32% salinity and 2 degrees Celsius sends a radio signal. How long will it take someone on the surface to receive the signal?
Relevant Equations: v*t=d
v=c/n

I thought I maybe need to find a way to calculate the reflective index (n) and using that calculating the velocity and then the time but I haven't managed to figure out how to get the reflective index? Would love your help.
I think you mean refractive index, but first google "radio waves through water"
 
haruspex said:
I think you mean refractive index, but first google "radio waves through water"
Yes thank you for the correction, I edited it in the question now (English isn't my first language 🙏🙏)
 
Welcome to PF.

xphrnzrjh said:
Homework Statement: We received the following riddle:
a diver 100m below surface, in 32% salinity and 2 degrees Celsius sends a radio signal. How long will it take someone on the surface to receive the signal?
You also need to do some reading about the attenuation of RF in conductive liquids like seawater versus the frequency of the RF signal. Submarines use ELF RF communication for a reason... :wink:
 
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