A seed is 15 mm in front of a convex lens, and the image of the ...

[crobinson2013]

A seed is 15 mm in front of a convex lens, and the image of the seed is 4.0 mm behind the lens. What is the focal length of the lens?
 
  A) 11 mm
  B) 5.5 mm
  C) 3.8 mm
  D) 3.2 mm

Question 2

A sample of ideal monatomic gas is cooled by 50.0C at constant volume by removing 831 J of energy from it. How many moles of gas are in the sample? (R = 8.31 J/mol  K)
 
  A) 2.50 mol
  B) 1.50 mol
  C) 1.33 mol
  D) 1.00 mol

[Chocorrol77]

Answer to Question 1

B

Answer to Question 2

C

[crobinson2013]

Thank you!

[Chocorrol77]

Always glad to help...