Quantum Physics · Paper 1 — Free Physics HL Practice Questions

An electron has a kinetic energy of $100 \text{ eV}$. What is its de Broglie wavelength? $(m_e = 9.11 \times 10^{-31} \text{ kg},\ h = 6.63 \times 10^{-34} \text{ J s},\ 1 \text{ eV} = 1.60 \times 10^{-19} \text{ J})$

An electron is trapped in a one-dimensional infinite potential well of length $L = 0.20$ nm. The ground state energy is $E_1 = 9.4$ eV. What is the energy of the $n = 4$ state?

A quantum dot confines an electron in a one-dimensional box of length $L$. The ground state energy is given by $E_1 = \dfrac{h^2}{8mL^2}$. When $L$ is doubled, the ground state energy changes by a factor of

A zinc plate, initially negatively charged, is connected to a gold-leaf electroscope. The plate is illuminated with ultraviolet radiation whose frequency exceeds the threshold frequency for zinc. Which observation is correct?