Final answer:
The drain current in an n-channel JFET is determined by the gate-source voltage.
Step-by-step explanation:
In an n-channel JFET, the drain current ID is determined by the gate-source voltage (VGS). The relationship between VGS and ID can be described by the drain current equation ID = IDSS(1 - VGS/VGS(off))^2, where IDSS is the drain current at VGS = 0 and VGS(off) is the gate-source voltage at which the drain current becomes zero.
Given that VGS(off) = V, and VGS = -4 V, we can substitute these values into the equation to find the drain current ID. The equation becomes ID = IDSS(1 + 4/V)^2.
Therefore, the answer is not explicitly provided in the given information and depends on the specific values of IDSS and V. Without these values, it is not possible to determine the exact drain current ID flowing in the circuit.