Electronics MCQs | Physics MCQs

Higher temperatures provide thermal energy to break covalent bonds, creating more free electrons and holes, which increases the density of charge carriers and thus conductivity.

An ideal op-amp has infinite input impedance (so it draws no current from the source) and zero output impedance (so it can deliver maximum voltage to the load).

A high input impedance is a key characteristic of an op-amp, allowing it to draw very little current from the input source.

The inverting configuration of an op-amp produces an output that is a magnified and inverted version of the input.

An oscillator is a self-sustaining circuit that generates a repetitive output signal.

This is a discrete, whole number, which is a digital quantity.

The binary system uses only two digits, 0 and 1, hence its base is 2.

The NAND gate is a universal gate because any other logic function can be created using only NAND gates.

This is the defining characteristic of the AND gate.

This represents the OR operation in Boolean algebra.

The NOT gate inverts the input signal, so it is also called an inverter.

This is the approximate ripple factor for a full-wave rectifier, which is much lower than that of a half-wave rectifier.

Alpha is the ratio of collector current to emitter current, and since some current is lost in the base, the collector current is always slightly less than the emitter current.

This is the correct formula for the voltage gain of a non-inverting op-amp, which is always greater than or equal to 1.

A flip-flop is a bistable multivibrator, meaning it has two stable states and can store one bit of information.

A full-wave rectifier is twice as efficient as a half-wave rectifier.

This is the only condition under which the output of a NOR gate is HIGH.

The calculation is (1 x 2^3) + (0 x 2^2) + (1 x 2^1) + (1 x 2^0) = 8 + 0 + 2 + 1 = 11.

The output is taken from the collector terminal.

When forward biased, electrons and holes recombine at the junction, releasing energy in the form of photons (light).

Depending on its biasing, a transistor can function as either a switch or an amplifier.

The XOR (Exclusive OR) gate gives a HIGH output only when the inputs are different.

This is the typical value for the potential barrier of a silicon p-n junction.

A filter, typically a capacitor, is used to remove the AC components (ripples) from the rectifier's output.

This is the term for the intrinsic gain of the amplifier itself, without any feedback circuit.

A bridge rectifier uses four diodes arranged in a bridge configuration to achieve full-wave rectification without a center-tapped transformer.

Zener breakdown happens in heavily doped diodes with a narrow depletion region, where the intense electric field is strong enough to directly break covalent bonds and create carriers.

The function of an AND gate is Y = A.B. Inverting this output with a NOT gate gives Y = (A.B)', which is the definition of a NAND gate.

Starting from the right: 1+0=1. 0+1=1. 1+1=0 with a carry of 1. 1+0+1(carry)=0 with a carry of 1. The final result is 10011.

The diode (D1) performs rectification (AC to pulsating DC). The capacitor (C) acts as a filter, smoothing the pulsating DC by storing and releasing charge, thereby reducing the ripple.

This is the correct simplification using the rules of Boolean algebra: A + A'B = (A + A')(A + B) = 1(A + B) = A + B.

The collector is moderately doped to reduce its resistance and is the largest region to dissipate heat.

In its open-loop configuration, an op-amp's output saturates to one of its supply voltages depending on which input has a higher potential.

This is the correct statement of De Morgan's first theorem, which relates the NAND and OR operations.

The wide depletion region in a reverse-biased junction offers a very high resistance to current flow.

The overlapping of these bands allows electrons to move freely, resulting in high conductivity.

This type of rectifier uses two diodes, one for each half of the AC cycle.

A transistor is an active component because it can amplify a signal, which requires an external power source.

The common-emitter configuration inverts the input signal, resulting in a 180-degree phase shift.

An LED (Light Emitting Diode) is specifically designed for this energy conversion.