Using Ohm's Law (V=IR), calculate the current, resistance, and voltage for the following circuits:

Voltage $V = 9$ V  
Resistance $R = 3$ $\Omega$

$$
I = \frac{V}{R}
$$

$$
I = \frac{9 \text{ V}}{3 \text{ } \Omega}
$$
$$
I = 3 \text{ A}
$$
The current flowing through the circuit is $\boxed{\text{3 A}}$.

Current $I = 0.5$ A  
Voltage $V = 120$ V

$$
R = \frac{V}{I}
$$

$$
R = \frac{120 \text{ V}}{0.5 \text{ A}}
$$
$$
R = 240 \text{ } \Omega
$$
The resistance of the bulb is $\boxed{\text{240 } \Omega}$.

Resistance $R = 15$ $\Omega$  
Current $I = 2$ A

$$
V = IR
$$

$$
V = (2 \text{ A})(15 \text{ } \Omega)
$$
$$
V = 30 \text{ V}
$$
The voltage across the resistor is $\boxed{\text{30 V}}$.