question_answer

                A charged particle moves through a magnetic field in a direction perpendicular to it. Then the:  

A)                                                                                                                                                                            acceleration remains unchanged                             

B)                 velocity remains unchanged

C)                 speed of the particle remains unchanged            

D)                 direction of the particle remains unchanged

Correct Answer: C

Solution :

                When a charged particle moves through a perpendicular magnetic field, then a magnetic force acts on it which changes the direction of particle but does not alter the magnitude of its velocity (i.e. speed).                                 Note:    If a charged particle moves at \[{{45}^{o}}\] to magnetic field then path of the particle will be a helix whose circular part has radius according to relation \[r=\frac{mv\,\sin \theta }{qB}\].