Question

A cyclotron is used to accelerate

• A. Only negatively charged particles
• B. Only positively charged particles
• C. Both negatively and positively charged particles
• D. Neutrons

Answer 1

The correct option is B

Only positively charged particles

Explanation for the correct option

B: Only positively charged particles

1. A cyclotron is designed to accelerate tiny positively charged particles of appropriate mass such as deuterons, alpha particles, etc.
2. The electric field generated by a cyclotron accelerates the positively charged particles.
3. The magnetic field generated by a cyclotron keeps the positively charged particle in circular orbits with a constant frequency.
4. The interaction of the magnetic field and the electric field with the positively charged particle leads to the acceleration of the positively charged particle.

Explanation for the incorrect options

A: Only negatively charged particles

1. The mass of an electron is very small as compared to a proton.
2. Due to the small mass of the electron, it gains a very high velocity because velocity is inversely proportional to the mass.
3. Due to the high velocity of the electron, it quickly goes out of the step with the oscillating electric field of the cyclotron and consequently cannot be accelerated.

C: Both negatively and positively charged particles

1. A cyclotron can only accelerate positively charged particles of appropriate mass.

D: Neutrons

1. Neutrons being charge-less are not influenced by the electric field of the cyclotron and consequently cannot be accelerated by the cyclotron.

Hence, option (B) is correct.