Corresponding to the transitive closure of a relation, since MR is a 4 x 4 matri
ID: 1887784 • Letter: C
Question
Corresponding to the transitive closure of a relation, since MR is a 4 x 4 matrix for this problem we have MR* = MR V MR^2 V MR^3 V MR^4 which also frequently written asMR* = MR + MR^2 + MR^3 + MR^4
Explain what MR* = MR + MR^2 + MR^3 + MR^4 means for the problem below.
Assume the Boolean matrix below is MR and that MR represents the relation R where R represents the connecting flights that an airline has between 4 cities: a, b, c, and d. so there is a 1 in row x column y iff there is a connecting flight between (from) city x and (to)city y That is, the rows of the matrix represent the cities of the origins of the flight and the columns represent the destination cities.
a b c d
a [ 1 1 0 0 ]
b [ 0 1 1 0 ]
c [ 0 0 1 1 ]
d [ 1 1 0 0 ]
Explanation / Answer
k, so calculate the energy of light at that wavelength E=hf h is planck's constant f is frequency now, subtract the kinetic energy of the ejected electron. that's how much energy is wasted trying to get the electron to leave cesium. It's called the work function, i believe, and it's the the absolute minimum energy you can put in to get an electron to leave. so, to calculate the frequency of light that will be just enough to eject an electron, set the work function equal to hf, and calculate f.