Final answer:
The peak output voltage of the amplifier in the midrange remains the same as at the upper critical frequency, which is 10 V. Therefore, the correct answer is 'D. 10 V.'
Step-by-step explanation:
The question involves understanding the relationship between the peak output voltage of an amplifier at its upper critical frequency and its voltage in the midrange. When an amplifier is operating at its upper critical frequency, it will output a voltage lower than that at the midrange frequency due to a decrease in gain. The peak output voltage given for the upper critical frequency is 10 V. We must use the relationship between peak voltage (Vpeak) and root mean square voltage (Vrms) to find the answer. The formula is Vpeak = Vrms * √2. Since the midrange voltage is not affected by the gain reduction at the critical frequency, we can calculate its peak voltage. If the upper critical frequency peak voltage is 10 V, and we divide this by √2 (approximately 1.414) to get the Vrms, we will have the midrange Vrms voltage, which upon multiplying by √2 will give us the midrange peak voltage.
Thus, calculating the midrange peak voltage gives us: (10 V / 1.414) * 1.414 = 10 V. Therefore, in the midrange, the peak voltage remains the same at 10 V. According to the options provided, the correct answer is 'D. 10 V.'