To solve for the time constant in the context of an electrical circuit, we typically need to know the relationship between current, voltage, resistance, and capacitance or inductance. The time constant, denoted by $\tau$, is the time it takes for the current or voltage in a charging or discharging circuit to reach approximately 63.2% of its final value.

However, just knowing the values of 1.5 amps and 1.5 seconds alone isn’t enough information to directly solve for the time constant without additional details about the circuit, like resistance, voltage, or the type of circuit (RC, RL, or other).

Here are a couple of typical scenarios where the time constant is used:

1. RC Circuit (Resistor-Capacitor): $\tau = R \cdot C$ where $R$ is resistance in ohms and $C$ is capacitance in farads.

2. RL Circuit (Resistor-Inductor): $\tau = \frac{L}{R}$ where $L$ is inductance in henries and $R$ is resistance in ohms.

If you’re dealing with a charging or discharging capacitor, the current in an RC circuit follows an exponential relationship:

$I(t) = I_0 \cdot e^{-\frac{t}{\tau}}$

Where:

• $I(t)$ is the current at time $t$,
• $I_0$ is the initial current,
• $\tau$ is the time constant,
• $t$ is the time.

If we rearrange this equation, we can solve for $\tau$ (if we have the current at a specific time $t$).

Would you be able to clarify the full context? For example, are you working with an RC or RL circuit, and do you have information about the initial current or voltage?

Let me know if you'd like to dive deeper into any part of this!