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WorksheetsSEMICONDUCTORS & SUPERCONDUCTORS
Total questions: 25
Worksheet time: 19mins
A semiconductor is a substance whose electrical conductivity lies between:
Metals and Non-metals
Insulators and Conductors
Solids and Liquids
None of these
A semiconductor is a substance whose forbidden energy is less than
(a)
Which of the following is an intrinsic semiconductor?
Silicon
Copper
Silver
Aluminium
The conductivity of a semiconductor increases with:
Increase in temperature
Decrease in temperature
Pressure
None of these
An extrinsic semiconductor is formed by:
Pure material only
Metals
Doping an impurity into intrinsic semiconductor
Alloys
Stoichiometric semiconductors are those in which:
Structure is amorphous
Impurities are intentionally added
Excess atoms are always present
Exact ratio of constituent elements is maintained
Non-stoichiometric semiconductors are characterized by:
Complete insulators
High electrical conductivity like metals
Deficiency or excess of constituent atoms
Perfect crystal structure
Zinc oxide (ZnO) with oxygen deficiency acts as:
p-type semiconductor
n-type semiconductor
Insulator
Metal
In forward bias of a PN junction diode, the barrier potential:
Decreases
Increases
Remains constant
Becomes zero
The depletion region in a PN junction is formed due to:
Heating effect
Applied external voltage
Diffusion of charge carriers across the junction
Free movement of electrons only
Doping with trivalent impurities (like B, Al, Ga) in silicon produces:
n-type semiconductor
p-type semiconductor
Insulator
Metal
Which of the following impurities is used to produce an n-type semiconductor?
Boron
Gallium
Indium
Arsenic
A superconductor is a material which, below a certain temperature,
Shows strong ferromagnetism
Shows infinite resistance
Shows zero electrical resistance
Shows high thermal conductivity
Shows strong ferromagnetism
The temperature below which a material becomes superconducting is called:
Transition temperature
Curie temperature
Critical temperature (Tc)
Debye temperature
Who discovered superconductivity in mercury in 1911?
Albert Einstein
Heike Kamerlingh Onnes
James Maxwell
Michael Faraday
The phenomenon in which a superconductor expels magnetic field lines when cooled below Tc is called:
Hall effect
Magnetoresistance
Meissner effect
Josephson effect
The Meissner effect demonstrates that superconductors are:
Perfect conductors only
Perfect diamagnets
Perfect paramagnets
Ferromagnetic
Type-I superconductors are also called:
Soft superconductors
Hard superconductors
High-temperature superconductors
Magnetic superconductors
Which of the following is a Type-II superconductor?
Lead (Pb)
Tin (Sn)
Niobium-Titanium (NbTi)
Mercury (Hg)
Magnetic levitation using superconductors is due to:
High resistivity
Ferromagnetism
Hall effect
Meissner effect
MRI machines use superconducting magnets because they:
Are cheap to build
Produce strong stable magnetic fields
Work at room temperature
Increase image contrast automatically
Which oxide ceramic is a famous high-Tc superconductor?
Al₂O₃
NaCl
YBa2Cu3O7 (YBCO)
SiO₂
Which one is an application of superconductors?
Magnetic Resonance Imaging (MRI)
Photovoltaic cells
LED bulbs
Transformers
The reason superconductors are useful in power transmission is:
They increase resistance
They can generate electricity
They eliminate power losses
They store energy like a capacitor
A half-wave rectifier converts:
AC to DC during one half cycle only
AC to DC during both half cycles
DC to AC
Constant voltage to variable voltage
