A(n) ______________ is an elementary particle with no charge.
a. electron
b. neutron
c. proton
d. atom
Question 2
A camera has a converging lens with a focal length of 56 mm. If the f-number is 2.8, what is the diameter of the lens (in mm)?
a. 10
b. 31
c. 0.50
d. 20
e. 50