A straight wire of length 20 cm floats in a horizontal perpendicular to a magnetic field of 1.5 T when a current of 1.3 A passes through the wire in a perpendicular direction to the magnetic field. Find the mass per unit length of the wire. (The wire is connected to a battery by ultra light flexible leads.)

An electron moves with a constant horizontal velocity of 3.0 × 106 m/s and no initial vertical velocity as it enters a deflector inside a tv tube. the electron strikes the screen after traveling 26 cm horizontally and 19 cm vertically upward with no horizontal acceleration. what is the constant vertical acceleration provided by the deflector? (the effects of gravity can be ignored.)