On December 26, 2004, a violent earthquake of magnitude 9.1 occurred off the
coast of Sumatra. This quake triggered a huge tsunami (similar to a tidal
wave) that killed more than 150,000 people. Scientists observing the wave on
the open ocean measured the time between crests to be 1.0 h and the speed of
the wave to be 800 km/h. Computer models of the evolution of this enormous
wave showed that it bent around the continents and spread to all the oceans of
the earth. When the wave reached the gaps between continents, it diffracted
between them as through a slit. (a) What was the wavelength of this tsunami?
(b) The distance between the southern tip of Africa and northern Antarctica is
about 4500 km, while the distance between the southern end of Australia and
Antarctica is about 3700 km. As an approximation, we can model this wave's
behavior by using Fraunhofer diffraction. Find the smallest angle away from
the central maximum for which the waves would cancel after going through each
of these continental gaps.