Which of the following are not electromagnetic waves?
Choose the correct answer.
Sound waves are mechanical waves, not electromagnetic waves.
Which of the following are electromagnetic waves?
Choose the correct answer.
Light is an electromagnetic wave.
Electromagnetic waves consist of:
Choose the correct answer.
The electric and magnetic fields of an electromagnetic wave are mutually perpendicular.
Electromagnetic waves always propagate in free space with the speed of:
Choose the correct answer.
Electromagnetic waves travel through vacuum at the speed of light.
The charge carriers in P-type substance are:
Choose the correct answer.
Holes are the majority charge carriers in P-type semiconductors.
The outermost orbit of each atom in silicon contains:
Choose the correct answer.
Silicon is tetravalent and has four valence electrons.
Germanium and silicon are the materials which are used as:
Choose the correct answer.
Germanium and silicon are common semiconductor materials.
Which of the following is a donor impurity?
Choose the correct answer.
Pentavalent impurities such as arsenic donate an extra electron.
Near absolute zero temperature, extrinsic semiconductors behave like:
Choose the correct answer.
At very low temperature, charge carriers in a semiconductor are not thermally excited.
P-type materials are obtained by adding germanium with:
Choose the correct answer.
Trivalent impurities create holes and produce P-type material.
A hole is equivalent to:
Choose the correct answer.
A hole behaves as a positive charge carrier in a semiconductor.
The charge carriers in N-type material are:
Choose the correct answer.
Electrons are the majority charge carriers in N-type semiconductors.
N-type materials are obtained by doping intrinsic germanium with:
Choose the correct answer.
Pentavalent impurities provide extra electrons.
A semiconductor diode when forward biased offers:
Choose the correct answer.
Forward bias reduces the depletion region and allows current to flow readily.
Rectification is the process of converting:
Choose the correct answer.
Rectification converts alternating current into direct current.
The device used for conversion of A.C. into D.C. is called:
Choose the correct answer.
A rectifier uses diodes to convert AC into pulsating DC.
A solar cell (or photovoltaic cell) is a device which converts:
Choose the correct answer.
A photovoltaic cell converts incident light energy directly into electrical energy.
The specially designed semiconductor diodes used as indicator lamps in electronic circuits are:
Choose the correct answer.
LEDs emit visible light when forward biased.
A PN junction conducts current only when it is:
Choose the correct answer.
In the idealized basic diode model, appreciable conduction occurs under forward bias.
The specially designed semiconductor diodes used as fast counters in electronic circuits are:
Choose the correct answer.
Photodiodes are designed for rapid response to changes in light.
