Hi,

Both M.Sc mathematics and MSc physics are good courses.

In academics field for the post like lecturer,teacher ,researcher or in coaching institutions both the courses have equal chances of hiring. If you are experts in your subject chances of you getting hired increases.

if you are searching for a career other then academics then these two subjects have different scope.

An Msc physics aspirant can work in atomic and space organisation,meteorology  Department, as a radiologist etc

An Msc mathematics person can work as quantitative developer, quantitative risk analyst, managing editor, etc