= 10. A current i(1) 0.02 sin(1000+ π/4) A flows through a two-terminal device with an impedance Z = 50- j40. Find the expression for the time variation of the ac voltage across the device. 11. The impedance of a branch is given by the expression Z = 50+ j40 N. Find the: (a) reactance, (b) admittance, (c) conductance, and (d) susceptance of the branch. - 12. The admittance of a branch is given by Y = 12 j5 m. Find the: (a) susceptance, (b) impedance, and (c) reactance of the element. 13. A voltage v(t) = 120√2 cos(377 +120°) V is applied across an RL branch with 10 and L=10 mH. Find an expression for the time variation of the current through the branch. R = 14. A current of i(t) = - 3 cos(t) 4 sin(1) A is made to flow through an RLC branch with R=20, L=2H, and C = 1 F. Find an expression for the time variation of the voltage across the branch. 15. A voltage v(t) = 100 sin(50r) mV is applied across an RC branch with R = 5 kn and C 10 μF. Find an expression for the time variation of the current through the branch. 16. Find the time dependence of the voltage source that must be applied to an RLC branch (R = 10, L= 1 H, and C 3/2 F) in order to achieve a current of i(t) cos(10) mA through the branch. = 17. A voltage v(r) = 120√√2 cos(2400r) V is applied across an LC branch with L = 1 mH and C = 1 μF. Find an expression for the time variation of the current through the branch. 18. When a voltage of v(r) = 20 cos(100r + 30°) V is applied across an RL branch, the resulting current through the branch is i(t) = 5 cos(100r - 45°) A. Find the values o- the resistance and inductance for this branch.