First one, for instance they become conductors or insulators depending on the temperature!
Answer:
The speed of light is faster in water. The Refractive index of water is 1.3 and the refractive index of glass is 1.5. From the equation n = c/v, we know that the refractive index of a medium is inversely proportional to the velocity of light in that medium. Hence, light travels faster in water.
Answer:
m v^2 / R = m g where gravitational force provides centripetal force
R = v^2 / g = 14.3^2 m/s / 9.8 m/s^2 = 20.9 m