The frequency of the radio wave is:

The wavelength of an electromagnetic wave is related to its frequency by the relationship

where c is the speed of light and f the frequency. Plugging numbers into the equation, we find

and this is the wavelength of the radio waves in the problem.
Answer: Heat
Explanation: Heat is a form of energy, and it is exchanged between bodys when they are not at the same temperature.
Heat is transferred from the body with higher temperature to the one with lower tempertature, this is so that in time they end up being at the same temperature.
This means that the one with lower temperature is the one who absorbs the heat, and the one with higher temperature transfer it.
The density of gold is 2.8 N / 15 = 0.18 units
The density of mercury is 0.13/1 = 0.13 units
Since the density of gold is more than density of mercury, it will sink.
Since the gold will sink, it will displace mercury, but less than its own volume
momm=massxvelocity
momm=1200x2.5=120x25=600x5=3000kgm/s