A spectral line is read
to have a wavelength of 4700A. What is
this in meters?

Explanation:

Angstrom can be defined as a metric unit of length for used for the measurement of the wavelength of light (optics) such as visible light, x-rays, ultraviolet light, gamma rays etc. The symbol for Angstrom is "A" and it is named after the 19th century physicist from Sweden, named Anders Jonas Angstrom.

Given the following data;

Wavelength of spectral line = 4700A

To convert this value to meters;

One Angstrom is mathematically equal to

Cross multiplying, we have;

X =  

Therefore, 4700A is equal to 4.7e-7 or 0.00000047 meters.