RRB Technician Grade I 13 March 2026 Paper

Concept:Magnetic flux measures the total magnetic field passing through a given surface, and it depends on three factors together: area, field strength, and orientation.Explanation:The magnetic flux is given by $\Phi = B A \cos \theta$.Here, $B$ is the magnitude of the magnetic field, $A$ is the area of the surface, and $\theta$ is the angle between the field direction and the normal to the surface.Hence, flux depends on the area $A$, the magnitude of $B$, and the orientation (angle $\theta$) together.Flux is maximum when the field is perpendicular to the surface, i.e., $\theta = 0^\circ$.Flux becomes zero when the field is parallel to the surface, i.e., $\theta = 90^\circ$.Therefore, option A correctly lists all the required factors.Answer:Option A: Area, magnitude of $B$, and its orientation.