Which of the following CANNOT be deflected by both electric and magnetic fields?

Analyze the question: We need the radiation that is not deflected by electric or magnetic fields. Deflection happens only if the radiation carries an electric charge.

Concept:

• Electric fields exert a force on charged particles (F = qE).
• Magnetic fields exert a force on moving charges (F = qvB).
• If q = 0, there is no force and so no deflection.

Checking each option:

• A. Gamma rays are high-energy electromagnetic waves (photons) with no charge. They are not deflected by either field.
• B. Alpha particles are helium nuclei with a charge of +2e. They are deflected by both fields.
• C. "Wave particles" is not a standard type of radiation, so it is not a meaningful choice here.
• D. Beta particles are fast electrons (or positrons) with a charge of -e (or +e). They are deflected by both fields, and more strongly than alpha particles because they are much lighter.

Answer: Gamma rays, which is option A.

Tip: Remember that charge decides deflection. Alpha (+) bends one way, beta (-) bends the other way, and gamma (0) goes straight. The mnemonic "Gamma is Neutral, so it goesGanga-straight" can help you recall that gamma rays pass straight through. Also, in a field, beta bends more than alpha because of its tiny mass.