In This OP-AMP circuit we know the Input Voltage (0.4V)
and we are asked to calculate the Output Voltage.
In addition we also need to calculate the load current iL.
The load we know it is very safe so the load current must be
much lower than the current that could be lethal
< 40mA.
10K
50k
wwwwww
1K9 = 1,000
+
0.4V
iL20KSL
Fig: 1
Fig: 2