In a double slit experiment, the ratio of slit width to the slit separation is 2.2 (five bright fringes in the central peak). If the slit separation is increased by a factor of three, keeping the slit width the same, how many fringes will now fit in the central peak? A: 13
B: 10
C: 15
D: 3

A5 foot by 5 foot box culvert is buried 6 feet beneath the surface of the ground. a crosssection of this very long culvert (into and out of the page) is illustrated below. assume that the soil in which the culvert is buried has the following properties: jt = 120 pcf, w = 12%, ko = 0.50, ka = 0.33, and kp = 3.00. calculate the total horizontal force per unit length of culvert (fh) felt on one of the vertical faces of the culvert.