MCQ Set 1- Electronics

The popular IC 741 is an operational amplifier. Operational amplifiers are widely used in electronic circuits for amplifying and processing signals. The IC 741 is a general-purpose operational amplifier that can be used in various applications such as amplification, filtering, and signal conditioning. It has a high gain, high input impedance, and low output impedance, making it suitable for a wide range of analog circuit designs.

PCM- Pulse Code Modulation

The modulation system employed in audio broadcast of TV is FM (Frequency Modulation). FM modulation is commonly used in broadcasting because it provides better sound quality compared to AM (Amplitude Modulation). FM modulates the frequency of the carrier signal with the audio signal, resulting in a varying frequency that corresponds to the audio waveform. This allows for a wider frequency range and less susceptibility to noise and interference, making it suitable for transmitting high-quality audio signals.

The superposition theorem is a method used to analyze linear circuits. It states that the response in any branch of a linear circuit can be determined by summing the responses caused by each individual source acting alone, while all other sources are turned off. Nonlinear elements, such as diodes or transistors, do not obey the principle of superposition, as their behavior is not linear. Therefore, the superposition theorem cannot be applied to networks containing nonlinear elements.

The common base configuration in a transistor amplifier has low input resistance because the input signal is applied to the emitter terminal, which is heavily doped and has a low resistance. On the other hand, it has high output resistance because the output signal is taken from the collector terminal, which is lightly doped and has a high resistance. This configuration allows for voltage amplification and impedance matching between the low impedance source and high impedance load.

AM- (Specifically Vestigial side band AM)

In a JFET (Junction Field-Effect Transistor), the gates are always reverse biased. This means that the voltage applied to the gate terminal is lower than the voltage at the source terminal. This reverse bias creates a depletion region in the channel, reducing the flow of current. By reverse biasing the gate, the JFET can control the current flow between the source and drain terminals. Therefore, the correct answer is reverse biased.

A Schering bridge is a type of bridge circuit that is specifically designed to measure capacitance. It is used to determine the unknown capacitance value by comparing it with a known standard capacitor. The bridge circuit is balanced when the ratio of the unknown capacitance to the known capacitance is equal to the ratio of the resistances in the bridge. This allows for accurate measurement of capacitance values. Therefore, the correct answer is capacitance.

When the values of all the resistors in a network are doubled, the total resistance in the network also doubles. According to Ohm's law (V = IR), if the resistance doubles and the voltage remains the same, the current flowing through the resistors will be halved. Since the voltage across each resistor is directly proportional to the current flowing through it, and the current is halved, the voltage across each resistor will also remain the same. Therefore, the correct answer is "Remains the same."

The correct answer is "Current series feedback." In an RC coupled amplifier with no emitter bypass capacitor, the output voltage is fed back to the input through a resistor in series with the input signal. This configuration is known as current series feedback, where the feedback signal is connected in series with the input signal. This type of feedback helps in stabilizing the gain and improving the linearity of the amplifier.

The human eye is most sensitive to the color green. This is because the human eye contains a higher number of green-sensitive cones compared to red or blue-sensitive cones. These cones are responsible for detecting color in the retina. Therefore, green light stimulates the cones more effectively, resulting in a higher sensitivity to green light.

Remains constant. Bandwidth increases by the same amount as reduction in
gain (1+AB); So GBW product remains the same.