Question

Assertion: A cyclotron cannot accelerate neutrons
Reason: neurons are neutral.
(A) Both Assertion and Reason are correct and Reason is the correct explanation for Assertion.
(B) Both Assertion and Reason are correct and Reason is not the correct explanation for Assertion.
(C) Assertion is correct but Reason is incorrect.
(D) Assertion is incorrect but Reason is correct.

Answer 1

Hint: Cyclotron uses magnetic force to accelerate particles through it. Magnetic forces are only experienced by moving charged particles.
Formula used: In this solution we will be using the following formulae;
\[F = qv \times B\] where \[F\] is the magnetic force on a particle, \[q\] is the charge of the particle, \[v\] is the velocity (in vector) of the particle, and \[B\] is the magnetic field at the location of the charge. The symbol \[ \times \] in this case signifies the cross product.

Complete answer:
A cyclotron is a type of particle accelerator used in accelerating particles with charge using a constant magnetic field. Generally, it is a class of devices which uses this principle to operate.
The cyclotron generates a magnetic field which is constant and directed in such a way that a particle entering into the field will circulate about a centre.
Recall that the force of a magnetic field is given by
\[F = qv \times B\] where \[F\] is the magnetic force on a particle, \[q\] is the charge of the particle, \[v\] is the velocity (in vector) of the particle, and \[B\] is the magnetic field at the location of the charge. The symbol \[ \times \] in this case signifies the cross.
Hence, when \[q\] is zero, the force is zero and the magnetic field cannot accelerate such particles.
Hence, since the neutron is neutral the cyclotron cannot accelerate it, thus, both assertion and reason are true and the reason is the explanation for the assertion.

Hence, the correct answer is A

Note: We should note that the direction of motion (i.e. force) of the particle is always perpendicular to the magnetic field. This is how the particles can go in a circle. The circle will be about an axis which is parallel to the field.