If the magnetic field strength is made half, how will a charged particle perpendicularly projected into the field change its radius?

The radius will become double.

The correct answer is Option (B) → The radius will become double.

Radius of the path $(R) = \frac{mv}{qB}$

$⇒R∝\frac{1}{B}$  [Inversely proportional]

∴ if magnetic field is made half, Radius will become twice.