A scuba diver is submerged in a pool of liquid having an index of refraction n. He looks up at the sun and measures its angle theta 1 from the vertical. He then rises to the surface and again measures its angle. What value does he get for the following values: n Theta 1 1.75E 00 2.00E 01 Make sure to express your answer in scientific notation with 2 decimal points.

Four point charges each having charge q are located at the corners of a square having sides of length a. find symbolic expressions for the following. (a) the total electric potential at the center of the square due to the four charges (use any variable or symbol stated above along with the following as necessary: ke.) vtotal= (b) the work required to bring a fifth charge p from infinity to the center of the square (use any variable or symbol stated above along with the following as necessary: w=