Question EXE.2.HL.TZ0.19
| Date | Example questions Example questions | Marks available | [Maximum mark: 8] | Reference code | EXE.2.HL.TZ0.19 |
| Level | HL | Paper | 2 | Time zone | TZ0 |
| Command term | Calculate, Predict, State | Question number | 19 | Adapted from | N/A |
State the de Broglie hypothesis.
[2]
a moving particle has wave properties ✓
de Broglie wavelength = Planck constant÷momentum (must define p if quoted as equation) ✓
A beam of electrons is accelerated from rest through a potential difference of 500 V maintained between two plates in a vacuum. The electrons then travel through a circular hole in the +500 V plate.
Calculate the maximum speed of the electrons in the beam.
[2]
use of ½ mv2 = eV ✓
1.33 × 107 m s−1 ✓
After passing through the circular hole the electrons strike a fluorescent screen.
Predict whether an apparatus such as this can demonstrate that moving electrons have wave properties.
[4]
idea that de Broglie wavelength and hole size must be similar ✓
Use of ✓
Leading to around 5 x 10−11 m (which is unrealistic for a practical situation) ✓
It would not be possible to construct this hole
OR
hole must be smaller than an atom so impossible ✓
