Ans is c because in reverse blocking mode .. junction j2 of scr is reversed biased so leakage current flow from cathode to anode..when it in reverse blocking mode

Reverse Blocking Mode in SCR

In the reverse blocking mode, an SCR (Silicon Controlled Rectifier) is connected in such a way that the anode is negative with respect to the cathode, and the gate terminal is left floating or disconnected. In this mode, the SCR is designed to block the reverse voltage and prevent the flow of current in the reverse direction.

Explanation of the Correct Answer (Option C)

The correct answer, option C, states that the leakage current flows from the cathode to the anode in the reverse blocking mode of an SCR. Let's discuss why this is the case:

1. Reverse Bias Condition:
In the reverse blocking mode, the anode of the SCR is made negative with respect to the cathode. This creates a reverse bias condition across the PN junctions of the SCR.

2. PN Junction Behavior:
In a reverse bias condition, the PN junction behaves like a reverse-biased diode. Under this condition, a small amount of leakage current can flow due to the minority carriers present in the PN junction depletion region. These minority carriers (electrons in the P-region and holes in the N-region) are generated thermally and contribute to the leakage current.

3. Leakage Current Flow:
Since the cathode of the SCR is connected to the N-type material, which contains the minority carriers (holes), the leakage current flows from the cathode to the anode. This is because the minority carriers are attracted towards the positive terminal (anode) of the reverse-biased PN junction.

4. Magnitude of Leakage Current:
The magnitude of the leakage current is typically very small in reverse blocking mode. It is on the order of microamps (μA) or nanoamps (nA), depending on the characteristics and quality of the SCR.

5. Importance of Leakage Current:
The leakage current is important because it indicates the reverse blocking capability of the SCR. A high-quality SCR should have a very low leakage current to effectively block the reverse voltage and prevent any significant current flow in the reverse direction.

Summary:
In summary, in the reverse blocking mode of an SCR, a small amount of leakage current flows from the cathode to the anode due to the presence of minority carriers in the reverse-biased PN junctions. This leakage current is crucial in determining the reverse blocking capability of the SCR and is typically very small in magnitude.