Explain the theory of electro-magnetism

What is the largest decimal number that can be represented by a binary number with 4 place values? (remember, each place in a binary number has a value of a power of 2, starting in the ones place with 20.)

Develop a function to create a document in the mongodb database “city” in the collection “inspections.” be sure it can handle error conditions gracefully. a. input -> argument to function will be set of key/value pairs in the data type acceptable to the mongodb driver insert api call b. return -> true if successful insert else false (require a screenshot)

Me with this program in c++ ! computers represent color by combining sub-colors red, green, and blue (rgb). each sub-color's value can range from 0 to 255. thus (255, 0, 0) is bright red. (130, 0, 130) is a medium purple. (0, 0, 0) is black, (255, 255, 255) is white, and (40, 40, 40) is a dark gray. (130, 50, 130) is a faded purple, due to the (50, 50, 50) gray part. (in other word, equal amounts of red, green, blue yield gray).given values for red, green, and blue, remove the gray part. ex: if the input is 130 50 130, the output is: 80 0 80. thus, find the smallest value, and then subtract it from all three values, thus removing the gray.