CBSE Questions for Class 12 Medical Physics Semiconductor Electronics: Materials, Devices And Simple Circuits Quiz 10 - MCQExams.com

Silicon is a semiconductor. If a small amount of As is added to it then its electrical conductivity
  • Decreases
  • Increases
  • Remains unchanged
  • Becomes zero
A transistor-oscillator using a resonant circuit with an inductor L ( of negligible resistance ) and a capacitor C in series produce oscillations of frequency f. If L is doubled and  C is changed to 4C, the frequency will be 
  • f/4
  • $$F_2=\dfrac{F_1}{2\sqrt{2}}$$
  • $$f/2\sqrt2$$
  • f/2
In negative logic, the logic state $$1$$ corresponds to.
  • Negative voltage
  • Zero voltage
  • More negative voltage
  • Lower voltage level
  • None of the above
Which of the following are the building blocks of all the circuits in a computer?
  • Circuit switch
  • Logic gates
  • Logical Operators
  • Instructions
  • None of the above
What is the name of the logic circuit which can add two binary digits?
  • Full adder
  • Half adder
  • Buffer
  • Register
  • None of the above
When an input electrical signal A$$=10100$$ is applied to a NOT gate, its output signal is _________________.
  • $$01011$$
  • $$10001$$
  • $$10101$$
  • $$00101$$
  • None of the above
Which logic gate is represented by the following logic gates?
851514_e617187a5da34b79b282a8c968e27e60.PNG
  • NOR
  • NAND
  • AND
  • OR
A pure semiconductor is __________.
  • an extrinsic semiconductor
  • an intrinsic semiconductor
  • p-type semiconductor
  • n-type semiconductor
When the maximum clock rate is quoted for a logic family, it applies to a
  • Shift register
  • Flip-flop
  • Counter
  • Single logic gate
If the load resistance decreases in a zener regulator, the zener current
  • Decreases
  • Stays the same
  • Increases
  • Equals the source voltage divided by the series resistance
The logic circuit shown in the figure represents characteristic of which logic gate?
961206_e00849401ad44862886174957b45bf03.png
  • OR gate
  • NOR gate
  • AND gate
  • NAND gate
Which of the following is/ are application (s) of flip-flop?
  • Bounce elimination switch
  • Latch
  • Counters
  • All of the above
Which of the following table helps in representing the previous and next of the sequential circuit prior to and after the clock pulse respectively?
  • Truth table
  • Characteristic table
  • Excitation table
  • None of the above
A digital gate can respond to an input signal in
  • About a second
  • About a hundredth of a second
  • A few billionth of a sec
  • A few millisecond
Which of the following circuit type is based upon time or clock pulse?
  • Combinational circuit
  • Sequential circuit
  • Full adder
  • None of these
Which one of the following can convert the alternating current into direct current?
  • Transformer
  • Motor
  • Dynamo
  • Rectifier
In J-K flip-flop the function K$$=$$J is used to realize.
  • D-flip-flop
  • S-R flip-flop
  • T-filip flop
  • Master-slave flip-flop
Master slave flip-flop is also referred to as the-
  • Level triggered flip-flop
  • Pulse  triggered flip-flop
  • Edge  triggered flip-flop
  • None of these
The propagation delay for ECL IC family is approximately ?
  • 2 ns
  • 10 ns
  • 25 ns
  • 50 ns
Which of following gates produces output of $$1$$?
Race condition occur in which flip-flop ______________.
  • RS flip flop
  • JK flip flop
  • D flip flop
  • T type flip flop
A photodiode is symbolised by the graphic.
Enhancement mode is used in
  • MOSFET
  • JFET
  • FET
  • None of the above
Which of the following have highest fan out?
  • TTL
  • DTL
  • ECL
  • CMOS
Which of the following input combinations is not allowed in an SR flip-flop?
  • S=0, R=0
  • S=0, R=1
  • S=1, R=0
  • S=1, R=1
A hole is drilled in a copper sheet. The diameter of the hole is 4.24 cm at 27.0$$^{\circ}$$C. What is the change in the diameter of the hole when the sheet is heated to 227$$^{\circ}$$C? Coefficient of linear expansion of copper is 1.70 x 10$$^{-5}$$ 
  • $$1.44 \times 10^{-2}$$ cm
  • $$2.44 \times 10^{-3}$$ cm
  • $$1.44\times 10^{-2}$$mm
  • $$2.44 \times 10^{-3}$$ mm
When the source voltage increases in a zener regulator, which of these currents remains approximately constant?
  • Series current
  • Zener current
  • Load current
  • Total current
With increase in temperature the conductivity of?
  • Metals increases and of semiconductor decreases
  • Semiconductors increases and of metals decreases
  • In both metals and semiconductors increases
  • In both metal and semiconductor decreases
An n stage ripple counter can count upto ___________.
  • 2n
  • 2n-1
  • n
  • 2n+1
Which of the following logic family is well suited for high speed operation ?
  • TTL
  • ECL
  • MOS
  • CMOS
If both J and K input is same, then it works like
  • D type flip-flop
  • T type flip-flop
  • Toggle switch
  • RS flip-flop
Which of the following is functionally complete set?
  • AND, OR
  • AND, XOR
  • NOT, OR
  • AND, OR, NOT
Minimum hardware required to construct a $$3 \times 8$$ decoder is using _______.
  • Two $$2 \times 4$$ decoders
  • Two $$2 \times 4$$ decoder and one $$ 1 \times 2$$ decoder
  • One $$2 \times 4$$ decoder
  • Depends upon the style of manufacturing
The correct output for the given circuit is:
992736_9e6d2986c51f489fa9d7f0b5d1f87f3f.png
LASER is an acronym for light amplification by.
  • Stimulated energetic radiation
  • Spontaneous emission of radiation
  • Stimulated emission of radiation
  • Spontaneous emission of radio waves
In a solid, an unfilled vacancy in an electronic energy level is called.
  • Hole
  • Majority carrier
  • Minority carrier
  • Electron
The graph given represents the I-V characteristics of a Zener diode. Which part of the characteristic curve is most relevant for its operation as a voltage regulator?
993200_deb94cc9480b4751a2f1423e9911ff07.png
  • $$ab$$
  • $$bc$$
  • $$cd$$
  • $$de$$
Zener diodes with breakdown voltage ranging over 2V- 200 V are commercially available. Breakdown voltage of a zener diode
  • Increases with increasing doping concentration
  • Decreases with increasing doping concentration
  • Does not depend on doping concentration
  • May increases or decreases with increasing doping concentration
The electrical conductivity of a semiconductor increases when emf radiation of wavelength shorter the $$2480$$ nm is incident in it. The band gap (in eV) for the semiconductor is?
  • $$0.9$$
  • $$0.7$$
  • $$0.5$$
  • $$1.1$$
Which of the following is a correct statement about current carrying conductor?
  • On increasing temperature drifts speed of free electron decreases
  • On increasing temperature drift speed of free electron increases
  • On increasing temperature, drift speed of free electron remains same.
  • On increasing P.D. average kinetic energy of electron decreases ( Neglected heating effect of electric current)
In the circuit shown in figure, the diode is ideal. The potential difference between A and B is?
993201_037ef3a077204b969fede4bdfa20ec81.png
  • $$V/4$$
  • V
  • Zero
  • $$V/2$$
Read the following diagram and tell which of the following statements are true:
992745_b153f7a1a8d64eb694710871c4504b64.PNG
  • In circuit 1 lamp does not glow but in circuit 2 lamp glows
  • In circuit 1 as well as 2 lamp does not glow
  • In circuit 1 lamp glows but in 2 lamp does not glow
  • In both circuit lamp glows
A full-wave rectifier circuit along with the output is shown. The contribution(s) from the diode $$1$$ is (are).
1012503_75e7a81f73194d4884dc2bb78e90df58.png
  • C
  • A, C
  • B, D
  • A, B, C, D
A capacitor is to be provide smoothing for a half wave rectifier. In which of the following diagrams is capacitor correctly connected? 
The dominant mechanisms for motion of charge carriers in forward and reversed biased silicon p-n junctions are :
  • Diffusion in forward bias, drift in reverse bias
  • Diffusion in both forward and reverse bias
  • Drift in both forward and reverse bias
  • None of these
For the plate voltage, the plate current in a triode valve is maximum when the potential of :
  • The gird is positive and plate is negative
  • The grid is zero and plate is positive
  • The grid is negative and plate is positive
  • The grid is positive and plate is positive
Select the correct statement from the following.
  • A diode can be used as a rectifier
  • A triode cannot be used as a rectifier
  • The current in a diode is always proportional to the applied voltage
  • The linear portion of the I-V characteristic graph of a triode is used for amplification without distortion
A non-conducting device is connected in a series circuit with a battery and a resistance. A current is found to pass through the circuit. If the polarity of the battery is reversed, the current drops to almost zero. The device may be
  • a p-n junction diode
  • an intrinsic semiconductor
  • a p-type semiconductor
  • a n-type semiconductor
In an experiment, the saturation in the plate current in a diode is observed at $$240\ V$$. But a student still wants to increase the plate current. It can done, if
  • The plate voltage is increased further
  • The plate voltage is decreased
  • The filament current is decreased
  • The filament current is increased
A diode can be used as
  • a demodulator
  • a modulator
  • an oscillator
  • a rectifier
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