Figure XXXXXXXXXXshows a circuit representation of a telegraph line. The resistance R is the line resistance and L is the inductance of the solenoid that activates the receiver’s clicker. The switch...

Figure 6.2.15 shows a circuit representation of a telegraph line. The resistance R is the line resistance and L is the inductance of the solenoid that activates the receiver’s clicker. The switch represents the operator’s key. Assume that when sending a “dot,” the key is closed for 0.1 s. Using the values R = 20 and L = 4 H, obtain the expression for the current i(t) passing through the solenoid.