Final answer:
Alpha particles will penetrate to a greater depth than protons in a water target due to their higher mass and charge.
Step-by-step explanation:
The alpha particle will penetrate to a greater depth than the proton in a water target. This is because alpha particles are more massive than protons and have a higher charge, which leads to a shorter range and greater penetrating ability through most materials, including water.
Alpha particles, which are helium nuclei, have a charge of +2e and are highly charged. As a result, they interact more strongly with ions in the air and electrons within materials, causing them to lose energy more quickly and have a shorter range. On the other hand, protons have a charge of +e, which is lower than the charge of an alpha particle, making them less penetrating.
It's important to note that the question specifically mentions both particles having the same velocity. If the velocities were different, it could also affect the penetrating ability, as well as other factors like the mass of the target and the energy of the particles.
Learn more about Particle Penetration