When the efficiency of RLC circuit is 50% then the circuit will be in:

Explanation

The correct answer is Not possible. In an RLC circuit, efficiency is typically maximized at resonance due to minimized impedance, allowing maximum power transfer. However, a 50% efficiency implies significant power losses, which can occur in non-ideal conditions with substantial resistance or other non-ideal factors. Therefore, the statement that the circuit is in resonance with 50% efficiency is not feasible under normal circumstances, as resonance would imply higher efficiency. The option 'Not in resonance' could potentially be correct if the question was about what conditions might lead to 50% efficiency, but given the options, 'Not possible' is the most accurate choice. The option 'None of the above' is incorrect because the question does provide a possible scenario even if not ideal.