A double-convex thin lens has radii of curvature of magnitude 46 ...

[michelleunicorn]

A double-convex thin lens has radii of curvature of magnitude 46 cm, and it is made of glass of index of refraction 1.60. What is the focal length of this lens?
 
  A) infinite B) -30 cm C) 18 cm D) 38 cm E) -19 cm

Question 2

A light beam from a 2.1-mW He-Ne laser has a wavelength of 633 nm. How many photons does the laser emit in one second?
 
  (h = 6.626  10-34 J  s, c = 3.00  108 m/s)
  A) 1.3  1016 B) 6.7  1015 C) 8.8  1015 D) 1.1  1016

[sultana.d]

Answer to Question 1

D

Answer to Question 2

B

[michelleunicorn]

Great answer, keep it coming

[upturnedfurball]

Thanks for the timely response, appreciate it