A certain radioactive source emits radiation that was found to be deflected by both magnetic and electric fields. The radiation is?

Analysis of the Question

The question asks us to identify a type of radiation based on its behavior in magnetic and electric fields. We need to recall the properties of the three main types of radioactive emissions: alpha particles, beta particles, and gamma rays.

Explanation of the Concept

In physics, the deflection of radiation in fields depends on whether the particles carry an electric charge:

• Alpha particles ($\alpha$): These are positively charged helium nuclei. They are deflected by both magnetic and electric fields.
• Beta particles ($\beta$): These are high-speed electrons (negatively charged). Because they carry a charge, they are also deflected by both magnetic and electric fields.
• Gamma rays ($\gamma$): These are electromagnetic waves (photons). They carry no electric charge and have no mass. Therefore, they are not deflected by magnetic or electric fields.
• X-rays and Ultra-violet rays: These are also forms of electromagnetic radiation and are not deflected by these fields.

Step-by-Step Solution

1. Evaluate the options: • Gamma rays, X-rays, and Ultra-violet rays are all electromagnetic waves. They are neutral (uncharged), so they pass through electric and magnetic fields without being deflected. • Beta rays consist of electrons. Electrons are charged particles.
2. Apply the principle: According to the Lorentz force law, a charged particle moving through a magnetic or electric field experiences a force that causes it to deflect. Since beta rays are charged, they will be deflected.
3. Conclusion: Among the given options, only beta rays possess the necessary charge to be deflected by both magnetic and electric fields.

Identify the Answer

The correct option is A.

Exam Tip

Remember the "Charge Rule":

• Charged (Alpha and Beta) = Deflected by fields.
• Uncharged (Gamma, X-rays, Light) = Not deflected by fields. This simple rule will help you answer any question regarding the nature of radiation in fields!