The gamma radiation emitted from a source of colbalt-60

Which of the following changes to a pipe would increase the conductance by a factor of 12? 1.quadrupling the length and tripling the radius.2.reducing the length by a factor of and doubling the radius.3.tripling the length and reducing the radius by a factor of .4.reducing the length but a factor of and doubling the radius.

What is hidden during a lunar eclipse? isn't the moon hidden?

Achild has maximum walking speed of 1.6 m/s. what is the length of the child's legs? 0.26 m