[amp_mcq option1=”2 k Ohm” option2=”10 k Ohm” option3=”20 k Ohm” option4=”1 k Ohm E. None of the above” correct=”option1″]
The correct answer is $\boxed{\text{C. 20 k Ohm}}$.
A current source is a device that maintains a constant current regardless of the voltage across it. The internal resistance of a current source is the resistance that appears in series with the current source when it is connected to a load. The larger the internal resistance, the less current will flow through the load.
For a current source to appear stiff, the load resistance must be much larger than the internal resistance. This is because the current source will only be able to maintain a constant current if the voltage across the load is small compared to the voltage across the internal resistance. If the load resistance is too small, the voltage across the load will be large enough to cause the current source to vary its output current.
In this case, the internal resistance of the current source is 100 kW. The largest load resistance that will allow the current source to appear stiff is 20 k Ohm. This is because the voltage across a 20 k Ohm resistor is 100 mV when a current of 1 mA flows through it. This is much smaller than the voltage across the internal resistance, which is 100 V. Therefore, the current source will be able to maintain a constant current of 1 mA when it is connected to a 20 k Ohm load.
Option A is incorrect because a 2 k Ohm load would cause the voltage across the load to be 200 mV, which is too large for the current source to maintain a constant current. Option B is incorrect because a 10 k Ohm load would cause the voltage across the load to be 100 mV, which is still too large for the current source to maintain a constant current. Option D is incorrect because a 1 k Ohm load would cause the voltage across the load to be 10 mV, which is too small for the current source to maintain a constant current. Option E is incorrect because there is a correct answer.