A zone plate is found to give series of images of a point source on its axis. If the strongest and the second strongest images are at distances of 0.30m and 0.06 m respectively from the zone plate (both from the same side remote from the source), calculate the distance of the source from the zone plate, principal focal length and the radius of the second zone. Assume λ = 6 x 10-7m. 

To protect all four receptacles on a branch circuit that surrounds a swimming pool, you would install which of the following configurations? a. gfci feed-through receptacle at the end of the load's circuit b. gfci-terminated receptacle at the beginning of the load's circuit c. gfci feed-through receptacle at the beginning of the load's circuit and the other receptacles connected to the load side of that receptacle d. gfci-terminated receptacle at each end of the load's circuit

The a metal retainer that keeps the rolling elements evenly spaced. n a. seal n b. separator n c. bearing n d outer race

Determine the age of a fossil if it had only one eighth of its original carbon-14 content remaining?