Question

1. the electrons in the diagram have slowed to a stop and have just started their return to the left - plate. what is the best estimate of the energy these electrons had when they were emitted? voltage 1.0 vot choose a metal calcium 0 0.5 ev 0 0.9 ev 0 1.1 ev 0 2.0 ev

Explanation:

Step1: Recall the work - energy theorem for electrons

The maximum kinetic energy of the emitted electrons (the energy they had when emitted) is equal to the stopping potential energy. When the electrons have just stopped and are about to turn back, the initial kinetic energy $K_{max}$ is equal to the work done by the electric field $W = eV_0$, where $e$ is the electron - charge and $V_0$ is the stopping potential.

Step2: Identify the stopping potential

From the diagram, the voltage (stopping potential $V_0$) is set to $1.1$ V.

Step3: Calculate the energy of the emitted electrons

The energy of the emitted electrons in electron - volts is equal to the stopping potential in volts because $E= eV_0$ and when $V_0 = 1.1$ V, $E = 1.1$ eV.

Answer:

C. 1.1 eV