The figure shows how the largest kinetic energy of the photoelectrons depends on the frequency of the light for two metals, P and Q. The two straight lines are parallel; they meet the frequency axis at $5.0 \times 10^{14}\ \text{Hz}$ for P and $7.5 \times 10^{14}\ \text{Hz}$ for Q. Light of frequency $12.5 \times 10^{14}\ \text{Hz}$ falls on both metals. What is the ratio of the largest speed of the electrons from P to that of the electrons from Q?

Fig. 1: A graph of the largest kinetic energy of photoelectrons, in electronvolts, against the frequency of the light, in units of 10 to the power 14 hertz. Two parallel straight lines rise from the frequency axis. Line P starts at 5.0 and line Q starts at 7.5 on the frequency axis; below these frequencies the kinetic energy is zero.