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

[xphrnzrjh]

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.

 

[haruspex]

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"

 

[xphrnzrjh]

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 )

 

[berkeman]

Welcome to PF.

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...