
| 1. | zero | 2. | \(-\dfrac{I_{0} R}{L}\) | 
| 3. | \(\dfrac{I_{0} R}{L}\) | 4. | \(\dfrac{I_{0} R}{2L}\) | 
A Blackbox (BB) which may contain a combination of electrical circuit elements (resistor, capacitor or inductor) is connected with other external circuit elements as shown below in figure (a). After the switch is closed at time \(t=0,\), the current \((I)\) as a function of time \((t)\) is shown in figure (b).
         
From this, we can infer that the Blackbox contains:
| 1. | a resistor and a capacitor in series. | 
| 2. | a resistor and a capacitor in parallel. | 
| 3. | a resistor and an inductor in series. | 
| 4. | a resistor and an inductor in parallel. | 
