How do you know the speed of an electromagnetic wave in a vacuum?

The image below shows numerous volcanic mountains in the pacific northwest. what is the most likely cause of the volcanic and earthquake activity in this region?

The coefficient of friction is a number that represents the resistance to sliding between two in contact with one another.

Question 1 (5 pts): what is the maximum distance for which you can you resolve the two individual headlights of an on-coming truck as two separate lights rather than one if the headlights are separated by 2.00 m and your eye has a diameter of 1.00 centimeter? assume a wavelength of 500 nm.