Multiple choice: a small amplitude transverse wave is travelling on a string. the frequency of the wave is suddenly doubled. which one of the following is a true statement?
a) the period of the wave doubles
b) the wavelength doubles
c) the speed of the wave doubles
d) the wavelength is cut in half
e) the speed of the wave is cut in half

Global warming will produce rising sea levels partly due to melting ice caps but also due to the expansion of water as average ocean temperatures rise. to get some idea of the size of this effect, calculate the change in length of a column of water 1.00 km high for a temperature increase of 1.00ºc. note that this calculation is only approximate because ocean warming is not uniform with depth. (answer in ×10^{-3} −3 m)

The electric potential v is constant everywhere within a certain region of space. which statement below is true? the choices are: the electric field is also constant (but not zero) within the region. a charged particle placed within the region will experience an electric force. the electric field is zero everywhere within the region. the electric field varies from place to place within the region.

What is the single most important equation in all of physics?