A conducting wire of length $0.5 \mathrm{~m}$ and mass $10 \mathrm{gm}$ is suspended in a uniform magnetic field of $0.5 \mathrm{~T}$ by two identical conducting springs with spring constant $k$ (see below).
A current of $1 \mathrm{amp}$ is sent through the springs and wire, and the wire is observed to move downward $1 \mathrm{~cm}$, stretching the springs.
a) In which direction is the current flowing?
b) Derive an expression for the spring constant in terms of known quantities and fundamental constants.
c) What is the numerical value of $k$ ?