Electron | MCQs

Explanation

The materials are called conductors if the electrons can move easily.

Conductors, like copper and aluminum.

It have low resistance and allow electrical current to flow freely through them.

Explanation

 A DIAC is a full-wave or bi-directional semiconductor switch that can be turned on in both forward and reverse polarities.

Explanation

The brightness of the waveform on the screen of a Cathode Ray Oscilloscope (CRO) is primarily controlled by the potential of the cathode.

Here's why:

• Cathode Ray Tube (CRT)
• Electron Beam Intensity
• Potential of the Cathode

Explanation

• When the frequency of the modulated wave is less than the frequency of the carrier wave, it indicates that the input signal is negative.
• This is a characteristic of amplitude modulation (AM) where the input signal is negative, resulting in a decrease in the amplitude of the carrier wave.

Explanation

• At the end of a communication system, such as a radio receiver or a phone, the signal is converted from radio waves (electromagnetic waves) to sound waves, which are perceived as sound by the human ear.
• This conversion is done through a speaker or earphone, which converts the electrical signal into sound waves.

Explanation

• Electrons exhibit diffraction effects because their de Broglie wavelength is similar to the spacing between atomic layers in a crystal.
• The de Broglie wavelength of an electron is given by λ = h/p, where h is Planck's constant and p is the electron's momentum.
• For electrons in a crystal, this wavelength is typically in the range of 0.1-1 nanometers, which is similar to the spacing between atomic layers in the crystal.
• As a result, electrons interact with the crystal lattice and exhibit diffraction effects, such as bending around corners or passing through the crystal in specific directions.

Explanation

In the dark, a Light Dependent Resistor (LDR) has a high resistance.

Explanation

A component that obeys Ohm's law is called an "Ohmic component."

Explanation

• In semiconductors, as the temperature increases, the conductivity increases.
• This is because heat energy excites more electrons into the conduction band, allowing them to flow more freely and increasing the conductivity.
• This is in contrast to metals, where conductivity typically decreases with increasing temperature.

Explanation

• The resistance of a filament lamp increases at higher voltages.
• The increase in voltage leads to an increase in current, which heats up the filament and increases the resistance.
• The increased temperature causes the atoms in the filament to vibrate more, making it more difficult for electrons to pass through and increasing the resistance.