To see from submarine and the ship at the surface of water, we use:
Telescope
Microscope
Periscope
Prism
When we heat the metal at high temperature they emit:
Holes
Protons
Neutrons
Electrons
The speed of light in water is:
2.0x103 ms-1
2.5x103 ms-1
2.3x108 ms-1
2.3x10-8 ms-1
