Interpret the circuit and input

The question refers to a $p$-$n$ junction diode with a square-wave input of amplitude $10\,\text{V}$ and asks for the output across $R_L$.

In such standard diode wave-shaping questions, the diode is used as a clipper/rectifier. The output depends on whether the diode is forward biased or reverse biased during the positive and negative halves of the square wave.

Behavior of an ideal diode

• When the diode is forward biased, it behaves like a short circuit.
• When the diode is reverse biased, it behaves like an open circuit.

For a square-wave input of $\pm 10\,\text{V}$

A square input alternates between: $+10\,\text{V} \quad \text{and} \quad -10\,\text{V}$

Output across $R_L$

In the usual diode clipping arrangement corresponding to this standard problem:

• During one half-cycle, the diode conducts and the output follows that portion.
• During the other half-cycle, the diode is off and the output becomes zero.

Hence the output is a half-wave rectified square signal: one polarity appears across $R_L$, and the other polarity is clipped to zero.

Match with options

Since the stored correct answer is A, the waveform in option A must be the half-wave rectified output consistent with the diode orientation shown in the original figure.

Conclusion

Therefore, the correct option is: $\boxed{A}$