Question

Which type of radiation is identical to an electron and is deflected toward the positive electrode as it passes between electrically charged plates?

Short answer

The radiation identical to an electron, deflected toward the positive electrode, is a beta particle.

Step-by-step solution

Identify Radiation Types

There are three main types of radiation: alpha particles, beta particles, and gamma rays. Alpha particles are positively charged, beta particles have negative charge, and gamma rays are neutral.

Determine Charge of an Electron

An electron has a negative charge. When identifying a type of radiation as an electron, it should carry the same charge.

Analyze Deflection in Electric Field

In an electric field, opposite charges attract, while like charges repel. Therefore, negatively charged particles will be attracted toward the positive electrode, while positively charged particles will be repelled.

Match Radiation to Description

Beta particles, which are identical to electrons, are negatively charged. This results in their deflection towards the positive electrode when passing through charged plates.

Identify the Radiation

Given that beta particles are identical to electrons and behave as described, the radiation deflected toward the positive electrode is a beta particle.

Key concepts

Alpha Particles

Alpha particles are a type of radiation that consists of two protons and two neutrons bound together. This cluster of fundamental particles is the same as a helium nucleus. Due to carrying a positive charge, alpha particles are uniquely heavy and massive among radioactive emissions.
Their positive charge means that they are repelled by positively charged electric fields and attracted to negative ones. Since they are relatively large, alpha particles have low penetration ability. They can be stopped by something as thin as a sheet of paper or even the outer layer of human skin, making external exposure less concerning. However, if alpha-emitting materials are ingested or inhaled, they can cause significant biological damage due to their high energy.
The interaction of alpha particles with matter is primarily through ionization, where they strip electrons away from atoms or molecules. This property is used in smoke detectors, where the alpha particles ionize the air along their path, contributing to the circuit that keeps the detector's alarm off unless disrupted by smoke.

Beta Particles

Beta particles are high-energy, high-speed electrons or positrons emitted from the nucleus of an atom during radioactive decay. As they have a negative charge (in the case of electrons), they are key to understanding the behavior of charged particles in electric fields.
In an electric field, beta particles will be deflected toward the positive electrode due to their negative charge. This defines their fundamental characteristic, distinguishing them from other forms of radiation. When detected in experiments, beta particles are seen moving rapidly, and their penetration power is greater than that of alpha particles. They can be halted by materials such as plastic or glass a few millimeters thick.
Their high-speed movement also means they can penetrate biological tissue more easily than alpha particles, posing a greater risk if not properly shielded in radioactive environments. Despite this, in medical treatments such as cancer radiotherapy, beta particles' property of penetrating soft tissue is exploited to target and destroy cancer cells with precision.

Gamma Rays

Gamma rays are a form of electromagnetic radiation, similar to X-rays, but with higher energy. They possess no mass and no charge, distinguishing them from alpha and beta particles. They are often emitted alongside alpha or beta particles when a radioactive atom decays, helping the atom shed excess energy.
Due to their neutral charge, gamma rays are not deflected by electric fields, differing markedly in behavior from charged radiation types like alpha and beta particles. However, their lack of charge also means they have significant penetration capabilities, able to travel through most materials. Shielding gamma rays often requires dense materials such as lead or several centimeters of steel.
In the medical field, gamma rays are harnessed for imaging and treatment, such as in PET scans or gamma knife surgery. Their ability to deliver concentrated energy doses makes them useful in cancer treatments, while their penetrative power serves as a critical tool for imaging internal bodily structures without invasive procedures.