Part A The de Broglie relation = h / p can be rewritten in terms of the wave num
ID: 1782982 • Letter: P
Question
Part A
The de Broglie relation =h/p can be rewritten in terms of the wave number k as p=k. Recall that wave number is defined by k=2/. Using the fact that =v/f, find the wave numbers k1 and k2 corresponding to frequencies f1 and f2.
Express your answer as two expressions separated by a comma. Use f1, f2, v, and .
2f1v,2f2v
Part B
Find an expression for the uncertainty k=k1k2 in the wave number. Use your results from Part A.
Express your answer in terms of quantities given in Part A.
k1, k2 =2f1v,2f2v
Explanation / Answer
We have,
k = 2 pi/lambda
lambda = v/f
k1 = 2 pi/lambda1 ; lambda1 = v/f1
k1 = 2 pi f1/v
similarly
k2 = 2 pi f2/v
Hence, k1,k2 = 2 pi f1/v, pi f2/v
B)deltaK = k1 - k2
delta k = 2 pi f1/v - 2 pi f2/v = 2 pi/v (f1 - f2)
Hence, delta k = 2 pi/v (f1 - f2) = 2 pi (f1 - f2)/v