When light of frequency 5.4 × 1014 Hz is shone on a metal surface the maximum energy of the electrons emitted is 1.2 × 10-19 J. If the same surface is illuminated with light of frequency 6.6 × 1014 Hz the maximum energy of the electrons emitted is 2.0 × 10-19 J. Use this information to calculate a value for h Plank’s constant?

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=