**1. An electron moves at 30,000 ms ^{-1}. What is its de Broglie wavelength?**

**2. What is its frequency?**

**3. What is its kinetic energy, in eV?**

From the top half of the fraction in the previous question:

**4. Given that it is travelling out of an electron gun, what was the potential difference between the anode and the cathode?**

2.56 mV – that's why we use eV!

**5. An electron is accelerated by a potential difference of 150 V. What is its frequency?**