CBSE
Multiple Choice QuestionsWhich logic gate is represented by the following combination of logic gates ?
OR
NOR
AND
NAND
Which type of gate the following truth table represents ?
NOT
AND
OR
NAND
The depletion layer of a p-n junction
is of constant width irrespective of the bias
acts like an insulating zone under reverse bias
has a width that increases with an increase in forward bias
is depleted of ions
In a common emitter configuration, a transistor has β = 50 and input resistance 1 kΩ. If the peak value of AC input is 0.01 V, then the peak value of collector current is
0.01 µA
0.25 µA
100 µA
500 µA
In a n-type semiconductor, which of the following statement is true ?
Electrons are majority carriers and trivalent atoms are dopants
Electrons are minority carriers and pentavalent atoms are dopants
Holes are minority carriers and pentavalent atoms are dopants
Holes are majority carriers and trivalent atoms are dopants
A junction diode has a resistance of 25 Ω when forward biased and 2500 Ω when reverse biased. The current in the diode, for the arrangement shown will be
The output (X) of the logic circuit shown in figure will be
X = A .B
A Si and a Ge diode has identical physical dimensions. The band gap in Si is larger than that in Ge. An identical reverse bias is applied across the diodes
The reverse current in Ge is larger than that in Si
The reverse current in Si is larger than that in Ge
The reverse current is identical in the two diodes
The relative magnitude of the reverse currents cannot be determined from the given data only
In a common emitter (CE) amplifier having a voltage gain G, the transistor used has transconductance 0.03 mho and current gain 25. If the above transistor is replaced with another one with transconductance 0.02 mho and current gain 20, the voltage gain will
1.5 G
Half-life of a radioactive substance is 20 min. The time between 20% and 80% decay will be
20 min
30 min
40 min
25 min
