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

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SUMMARY

The discussion centers on calculating the time it takes for a radio signal transmitted by a diver 100 meters underwater in seawater with 32% salinity and at 2 degrees Celsius to reach the surface. The key equations involved are the velocity equation (v*t=d) and the refractive index equation (v=c/n). Participants emphasize the importance of understanding the refractive index of seawater and the attenuation of RF signals in conductive liquids, particularly for effective communication underwater.

PREREQUISITES
  • Understanding of refractive index calculations
  • Knowledge of radio wave propagation in seawater
  • Familiarity with the concept of signal attenuation in conductive mediums
  • Basic physics principles related to velocity and distance
NEXT STEPS
  • Research the refractive index of seawater at various salinities and temperatures
  • Learn about radio wave attenuation in seawater and its impact on signal strength
  • Explore the use of Extremely Low Frequency (ELF) RF communication in submarines
  • Study the mathematical relationship between velocity, refractive index, and time
USEFUL FOR

This discussion is beneficial for physics students, marine communication engineers, and anyone interested in the principles of radio wave transmission in underwater environments.

xphrnzrjh
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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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