Our physics expert picks his top-five equations, plus a scheme to supply US power needs with a bucket of baseballs. Thanks, ...

To calculate the force on a wire carrying a current at right angles to a magnetic field, use the equation: 2 A flows through a 50 cm wire. Calculate the force acting on the wire when it is placed ...

With forefinger (magnetic field) pointing left to right, and second finger (current) pointing down, your left thumb (force) will point towards you. This is the direction in which the force acts.