A silicon NMOS has Id = 3 mA, Vgs = 2 V, Vds = 4 V, and Vt = 0.5 V. If the thickness of oxide is 500 A°, the aspect ratio of the device at room temperature is___ [take: the mobility of charge carriers as 0.13 m2/V-s and the relative permittivity as 12]
1
10.75
2
9.70
3
12.5
4
22.75