The total energy E(n)E(n)E(n) released by a sequence of n n\,n laser pulses in a laboratory experiment is given by the sum E(n)=∑j=0n(2j)4E(n) = \sum_{j=0}^{n} (2j)^4E(n)=∑j=0n(2j)4 millijoules, where n n\,n is a positive integer. The specific energy produced by the nnn-th pulse is defined as P(n)=E(n)−E(n−1)P(n) = E(n) - E(n-1)P(n)=E(n)−E(n−1).
Determine the specific energy released by the 3rd pulse, P(3)P(3)P(3), and the 10th pulse, P(10)P(10)P(10).
Find the pulse number n n\,n such that the specific energy released is P(n)=8.1×109P(n) = 8.1 \times 10^9P(n)=8.1×109 millijoules.
Practise AQA A Level Maths 1.7 D: Sequences and series with exam-style questions for A Level Maths. 267 questions covering 1.7.1 Binomial expansion, 1.7.2 Types of sequence (A-level only), 1.7.3 Sigma notation (A-level only), 1.7.4 Arithmetic sequences and series (A-level only), 1.7.5 Geometric sequences and series (A-level only), and 1.7.6 Sequences and series in modelling (A-level only), matched to the AQA A Level Maths (7357) specification and written in Paper 1, Paper 2 and Paper 3 style. Every question includes a full worked solution and mark scheme, so you can see where marks are awarded rather than just whether you got the answer right.
