Physics M.C.Q (1 Marks)

Which of the following logic gate is an universal gate(a) OR(b) NOT(c) AND(d) NOR

The output of OR gate is 1(a) If both inputs are zero(b) If either or both inputs are 1(c) Only if both input are 1(d) If either input is zero

Which logic gate is represented by the following combination of logic gates

A gate in which all the inputs must be low to get a high output is called(a) A NAND gate(b) An inverter(c) A NOR gate(d) An AND gate

The output of a NAND gate is 0(a) If both inputs are 0(b) If one input is 0 and the other input is 1(c) If both inputs are 1(d) Either if both inputs are 1 or if one of the inputs is 1 and the other 0

If A and B are two inputs in AND gate, then AND gate has an output of 1 when the values of A and B are(a) A = 0, B = 0(b) A = 1, B = 1(c) A = 1, B = 0(d) A = 0, B = 1

The given truth table is of

How many NAND gates are used to form an AND gate(a) 1 (b) 2(c) 3  (d) 4

A gate has the following truth table The gate is (a) NOR  (b) OR(c) NAND  (d) AND

A logic gate is an electronic circuit which(a) Makes logic decisions(b) Allows electrons flow only in one direction(c) Works binary algebra(d) Alternates between 0 and 1 values

The logic behind ‘NOR’ gate is that it gives(a) High output when both the inputs are low(b) Low output when both the inputs are low(c) High output when both the inputs are high(d) None of these

Boolean algebra is essentially based on(a) Truth(b) Logic (c) Symbol(d) Numbers

A truth table is given below. Which of the following has this type of truth table (a) XOR gate(b) NOR gate(c) AND gate(d) OR gate

In a transistor in CE configuration, the ratio of power gain to voltage gain is(a) a        (b) b / a(c) ba(d) b

NPN transistor are preferred to PNP transistor because they have(a) Low cost(b) Low dissipation energy(c) Capability of handing large power(d) Electrons having high mobility than holes

Consider an NPN transistor amplifier in common-emitter configuration. The current gain of the transistor is 100. If the collector current changes by 1 mA, what will be the change in emitter current(a) 1.1 mA(b) 1.01 mA (c) 0.01 mA(d) 10 mA

Which of the following is used to produce radio waves of constant amplitude(a) Oscillator (b) FET (c) Rectifier(d) Amplifier

In NPN transistor the collector current is 10 mA. If 90% of electrons emitted reach the collector, then(a) Emitter current will be 9 mA (b) Emitter current will be 11.1 mA(c) Base current will be 0.1 mA(d) Base current will be 0.01 mA

When NPN transistor is used as an amplifier(a) Electrons move from base to emitter (b) Electrons move from emitter to base (c) Electrons moves from base to emitter (d) Holes moves from base to emitter

Correct relation for triode is

In case of NPN-transistors the collector current is always less than the emitter current because(a) Collector side is reverse biased and emitter side is forward biased(b) After electrons are lost in the base and only remaining ones reach the collector(c) Collector side is forward biased and emitter side is reverse biased(d) Collector being reverse biased attracts less electrons

In a common base amplifier circuit, calculate the change in base current if that in the emitter current is 2 mA and a = 0.98(a) 0.04 mA(b) 1.96 mA(c) 0.98 mA(d) 2 mA

For a transistor, the current amplification factor is 0.8. The transistor is connected in common emitter configuration. The change in the collector current when the base current changes by 6 mA is (a) 6 mA(b) 4.8 mA(c) 24 mA(d) 8 mA

The part of a transistor which is heavily doped to produce a large number of majority carriers, is(a) Base(b) Emitter(c) Collector(d) None of these

The most commonly used material for making transistor is(a) Copper(b) Silicon(c) Ebonite(d) Silver

In a PNP transistor the base is the N-region. Its width relative to the P-region is (a) Smaller(b) Larger(c) Same (d) Not related

A transistor is used in common emitter mode as an amplifier. Then(a) The base-emitter junction is forward biased(b) The base-emitter junction is reverse biased(c) The input signal is connected in series with the voltage applied to the base-emitter junction(d) a, c

For a transistor the parameter b = 99. The value of the parameter a is(a) 0.9(b) 0.99(c) 1  (d) 9

The transistors provide good power amplification when they are used in(a) Common collector configuration(b) Common emitter configuration(c) Common base configuration     (d) None of these

Least doped region in a transistor(a) Either emitter or collector(b) Base(c) Emitter(d) Collector

Symbolic representation of photodiode is

In P-N junction, the barrier potential offers resistance to(a) Free electrons in N region and holes in P region(b) Free electrons in P region and holes in N region(c) Only free electrons in N region(d) Only holes in P region

The width of forbidden gap in silicon crystal is 1.1 eV. When the crystal is converted in to a N-type semiconductor the distance of Fermi level from conduction band is(a) Greater than 0.55 eV (b) Equal to 0.55 eV(c) Lesser than 0.55 eV (d) Equal to 1.1 eV

Zener diode is used as(a) Half wave rectifier(b) Full wave rectifier(c) ac voltage stabilizer(d) dc voltage stabilizer

The transfer ratio of a transistor is 50. The input resistance of the transistor when used in the common-emitter configuration is 1 KW. The peak value for an A.C input voltage of 0.01 V peak is(a) 100 mA(b) 0.01 mA(c) 0.25 mA(d) 500 mA

Which of the following is true (a) Common base transistor is commonly used because current gain is maximum(b) Common emitter is commonly used because current gain is maximum(c) Common collector is commonly used because current gain is maximum (d) Common emitter is the least used transistor

In the case of constants a and b of  a transistor(a) a = b(b) b < 1   a > 1(c) ab = 1(d) b > 1  a < 1

A NPN transistor conducts when(a) Both collector and emitter are positive with respect to the base (b) Collector is positive and emitter is negative with respect to the base(c) Collector is positive and emitter is at same potential as the base(d) Both collector and emitter are negative with respect to the base

The emitter-base junction of a transistor is …… biased while the collector-base junction is ……. biased(a) Reverse, forward(b) Reverse, reverse(c) Forward, forward (d) Forward, reverse

An oscillator is nothing but an amplifier with(a) Positive feed back(b) Large gain(c) No feedback(d) Negative feedback