Final answer:
Without additional information such as resistance value or the time constant, it's not possible to provide the exact current at 13.5 ms in the inductor circuit.
Step-by-step explanation:
The question pertains to the current in an inductor circuit at a given time after being connected to a battery. The time constant (τ) for an inductor circuit can be calculated using the formula τ = L/R, where L is the inductance and R is the resistance. However, an additional detail necessary to accurately answer the question, such as the resistance value or a time constant, is not provided. Without this information, the exact current at 13.5 ms cannot be calculated.