Fig. 3.1 shows the speed/time graph for a journey travelled by a tractor Q
R
6
spood
m/s
4
2.
P
O
S
200
0
50
100
170
time/s
Fig. 3.1
(a) Use the graph to describe the motion of the tractor during each of the marked sections,
OP
РО
QR
RS
[4)

An electron is trapped at a defect in a crystal. the defect may be modeled as a one-dimensional, rigid-walled box of width 1.00 nm. (a) sketch the wavefunctions and probability densities for the n 1 and n 2 states. (b) for the n 1 state, nd the probability of nding the electron between x1 0.15 nm and x2 0.35 nm, where x 0 is the left side of the box. (c) repeat (b) for the n 2 state. (d) calculate the energies in electron volts of the n 1 and n 2 states