A thin beam of light of wavelength 625 nm goes through a thin ...

[nelaaney]

A thin beam of light of wavelength 625 nm goes through a thin slit and falls on a screen 3.00 m past the slit.
 
  You observe that the first completely dark fringes occur on the screen at distances of 8.24 mm from the central bright fringe, and that the central bright fringe has an intensity of 2.00 W/m2 at its center.
  (a) How wide is the slit?
  (b) What is the intensity of light at a point on the screen that is one-quarter of the way from the central bright fringe to the first dark fringe?

Question 2

A 50.0-g sample of a material at 80.0C is dropped into a calorimeter containing 100.0 g of water at 20.0C. When the mixture reaches thermal equilibrium, it is at a temperature 24.0C.
 
  If heat transfer to the walls of the calorimeter is negligible, what is the specific heat of the material?
  A)
 
  0.143 cal/(gC)
  B)
 
  0.322 cal/(gC)
  C)
 
  0.221 cal/(gC)
  D)
 
  0.437 cal/(gC)
  E)
 
  0.0714 cal/(gC)

[choc0chan]

Answer to Question 1

(a) 0.228 mm (b) 1.62 W/m2

Answer to Question 2

A