A thin strip 10 cm long is on a U shaped wire of negligible resistance and it is connected to a spring of spring constant 0.5 Nm^-1 (see figure). The…

A thin strip $\displaystyle 10$ cm long is on a U shaped wire of negligible resistance and it is connected to a spring of spring constant $\displaystyle 0.5 \mathrm{Nm}^{-1}$ (see figure). The assembly is kept in a uniform magnetic field of $\displaystyle 0.1$ T. If the strip is pulled from its equilibrium position and released, the number of oscillations it performs before its amplitude decreases by a factor of e is N. If the mass of the strip is $\displaystyle 50$ grams, its resistance $\displaystyle 10 \Omega$ and air drag negligible, N will be close to :