29.6 Exercise 1

The least massive particle known to exist is the electron neutrino. Though scientists once believed that it had no mass, like the photon, they have now determined that this particle has an extremely low mass, equivalent to a few electron volts. Assuming a mass of 2.2 eV/c² (or 3.9 × 10^–36 kg) and a speed of 4.4 × 10⁶ m/s, which of the following values equals the neutrino’s de Broglie wavelength?

1. 3.8 × 10^–5 m
2. 4.7 × 10^–7 m
3. 1.7 × 10^–10 m
4. 8.9 × 10^–14 m