(Solved): please show all work  a) A physics lab instructor is working on a new demonstration. She attach ...

a) A physics lab instructor is working on a new demonstration. She attaches two identical metal spheres with mass \( m=0.220 \mathrm{~g} \) to cords of length \( L \) as shown in the figure. (1) Both spheres have the same charge of \( 7.60 \mathrm{nC} \), and are in static equilibrium when \( \theta=4.70^{\circ} \), What is \( L \) (in \( m \) )? Assume the cords are massless. \( m \) b) What If? The charge on both spheres is increased until each cord makes an angle of \( \theta=9.40^{\circ} \) with the vertical. If both spheres have the same electric charge, what is the charge (in nC) on each sphere in this case? \( \mathrm{nC} \)