6 The probability that a particular type of light bulb is defective is 0.01 . A large number of these bulbs are tested, one by one. Assuming independence, find the probability that the tenth bulb tested is the first to be found defective. The first defective bulb is the \(N\) th to be tested. Write down the value of \(\mathrm { E } ( N )\). Find the least value of \(n\) such that \(\mathrm { P } ( N \leqslant n )\) is greater than 0.9 .