A 5.30 μC charge is moving at a constant speed of 7.80 × 10⁵ m/s in the x direction relative to a reference frame. What is the magnitude of the charge's velocity?
(a) 5.30 μC
(b) 7.80 × 10⁵ m/s
(c) 5.30 μC × 7.80 × 10⁵ m/s
(d) √((5.30 μC)² + (7.80 × 10⁵ m/s)²)
