NEET UG Semiconductor Electronics: Materials, Devices and Simple Circuits — practice questions
80 free MCQs with worked solutions. Tap any question for the answer + explanation, or practice them all in the app.
Practice NEET UG Semiconductor Electronics: Materials, Devices and Simple Circuits in the app →In which year was the transistor discovered, after which vacuum tubes gave way?In a vacuum tube, the electrons that carry the current are supplied by:Compared with vacuum tubes, semiconductor devices typically have:Galena, a crystal once used to detect radio waves, is chemically:Which pair of elements are elemental semiconductors?Gallium arsenide (GaAs) is an example of a:In metallic conductors, the conduction band and valence band:For a germanium atom, the outermost electrons lie in which orbit?At absolute zero, the valence band of pure silicon is:A solid behaves as an insulator when its energy band gap is roughly:In the diamond-like lattice of silicon, each atom has how many nearest neighbours?The shared electron pairs between neighbouring Si atoms form a:Under an applied electric field, holes in a semiconductor move towards the:At thermal equilibrium in a semiconductor, the rate of carrier generation is:C, Si and Ge share a lattice type, yet carbon is an insulator because its:Doping a pure semiconductor usually adds impurity at a level of a few:Which element is a pentavalent dopant for silicon?Which dopant turns germanium into a p-type semiconductor?The energy needed to free the fifth electron of a donor atom in silicon is about:The energy band gap of silicon at room temperature is about:Diamond, a crystalline form of carbon, has an energy gap of about:Tin is a group IV element, yet it is a metal because its energy gap is:A pentavalent impurity in silicon is called a donor because it:In n-type Si, the number of electrons supplied by donor atoms depends mainly on the:Donor doping lowers the hole count in Si because:In p-type Si, an ionised acceptor atom carries an effective charge that is:How many holes does each trivalent acceptor atom contribute?In the band structure of n-type silicon, the donor level lies:A crystal with 5 x 10^28 Si atoms per m^3 gets 1 ppm of arsenic. Its electron density is about:Why can't pressing p and n slabs together form a junction?The two key processes that occur while a p-n junction forms are:An electron diffusing from n-side to p-side leaves behind:The electric field in the depletion region of a p-n junction points:The motion of charge carriers caused by an electric field is called:At equilibrium, the net current through an unbiased p-n junction is:Forward biasing a p-n junction diode means connecting:A diode with built-in potential V0 is forward biased by V. Its effective barrier height is:Under forward bias, the depletion layer of a p-n junction:Under forward bias, carriers crossing to the opposite side is:Below breakdown, a diode's reverse current is limited by the:The reverse voltage at which a diode's reverse current rises sharply is the:If a diode's current is allowed to exceed its rated value, the diode is destroyed by:The cut-in voltage of a silicon junction diode is about:A reverse biased diode's tiny, steady current is called the:The dynamic resistance of a diode is defined as the ratio of:A diode's voltage rises from 0.7 V to 0.8 V as its current goes from 10 mA to 20 mA. Its rd is:A reverse biased diode passes 1 microampere at 10 V. Its reverse resistance is:In a half-wave rectifier, output appears across the load only while the diode is:A rectifier diode's reverse breakdown voltage must be:A two-diode full-wave rectifier needs a secondary that is:A full-wave rectifier that needs no centre-tap transformer uses how many diodes?To smooth a rectifier's output, a filter capacitor is connected:Capacitor input filters use large capacitors mainly to make the:With a capacitor input filter, the dc output voltage is close to the rectified:In GaAs, the semiconductor type can also be set by altering the:Television CRT monitors, based on vacuum tube principles, have been replaced by:The invention of the p-n junction in 1939 is usually credited to:Who set out the modern theory of p-n junctions in the classic 1950 book on electrons and holes?Solar cells and light-emitting diodes are, at heart, simply:A reverse biased p-n junction usually breaks down through which two processes?A varactor diode uses its reverse bias voltage to vary its:A device that converts alternating current into direct current is a:A device that converts direct current into alternating current is called:How many diodes does half-wave rectification of a single-phase supply need?Mathematically, ideal full-wave rectification of a signal corresponds to the:For equal output, a centre-tap rectifier's secondary needs, versus a bridge:The forward voltage drop of a Schottky diode is typically around:A silicon bridge rectifier gets a 12 V peak ac input. Its peak output is about:With 50 Hz mains, the main ripple in a full-wave rectifier's output is at:A half-wave rectifier runs from a 60 Hz supply. Its output ripple frequency is:Compared with a capacitor-input filter, a choke-input filter gives:The thermionic vacuum diode called the Fleming valve was invented in:The release of electrons from a heated filament, called the Edison effect, is:The earliest type of semiconductor diode, used in early radio sets, was the:Which Indian scientist co-invented the crystal detector around 1902?Germanium diodes have an edge over silicon in low-voltage circuits due to their:In gas heating systems, flame rectification is used to:Half-wave rectifiers, compared with full-wave rectifiers, produce:Polypyrrole and polyaniline are examples of:Why does pure Si conduct slightly at room temperature?