A certain fuse blows if the current in it exceeds 1.0 A, at which ...

[folubunmi]

A certain fuse blows if the current in it exceeds 1.0 A, at which instant the fuse melts with a current density of 620 A/cm2. What is the diameter of the wire in the fuse?
 
  A) 0.45 mm
  B) 0.63 mm
  C) 0.68 mm
  D) 0.91 mm

Question 2

A 35 mm camera equipped with a 45 mm focal length lens is used to photograph a tree 15 m tall. The aperture of the lens is set at f/2. The aperture diameter at f/2, in mm, is closest to:
 
  A) 23
  B) 14
  C) 18
  D) 27
  E) 32

[bulacsom]

Answer to Question 1

A

Answer to Question 2

A

[folubunmi]

Thank you!

[bulacsom]

Always glad to help...