When do you use Hfus? Why can’t we use q=mcΔt at this point?

when there is heat of fusion Hfus we can't use q=mcΔt because there Is a change of state from solid to liquid with out a corresponding change in temperature (hidden heat).

Therefore whenever there is a change from one state to another there is no change in temperature

So instead of using q=mcΔt

We use q=m*Hfus

What is specific Latent heat of fusion?

Specific Latent heat of fusion of a substance is the quantity of heat required to change a kilogram of a substance from the solid state to The liquid state at melting point.

The S. I unit is in joules per kilogram (j/kg)

The massive mid-ocean ridge system is a continuous range of underwater volcanoes that wraps around the globe like seams on a baseball, stretching nearly 65,000 kilometers (40,390 miles).

The majority of the system is underwater, with an average water depth to the top of the ridge of 2,500 meters (8,200 feet).

Mid-ocean ridges occur along divergent plate boundaries, where new ocean floor is created as the Earth’s tectonic plates spread apart.

As the plates separate, molten rock rises to the seafloor, producing enormous volcanic eruptions of basalt.

The speed of spreading affects the shape of a ridge – slower spreading rates result in steep, irregular topography while faster spreading rates produce much wider profiles and more gentle slopes.

tell me if this is wrong please