MCQOPTIONS
Saved Bookmarks
MCQOPTIONS
This section includes 1017 Mcqs, each offering curated multiple-choice questions to sharpen your Electronics & Communication Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 401. |
In modern MOSFETS, the material used for the gate is |
| A. | heavily doped polycrystalline silicon |
| B. | epitaxial grown silicon |
| C. | 2, 1, 4, 3 |
| D. | 1, 2, 4, 3 |
| Answer» D. 1, 2, 4, 3 | |
| 402. |
In N-type semiconductor |
| A. | electrons are majority carriers while holes are minority carriers |
| B. | electrons are majority carriers while holes are majority carriers |
| C. | both electrons as well as holes are majority carriers |
| D. | both electrons as well as holes are minority carriers |
| Answer» B. electrons are majority carriers while holes are majority carriers | |
| 403. |
In monolithic ICs, all the components are fabricated by |
| A. | diffusion process |
| B. | oxidation |
| C. | evaporation |
| D. | none |
| Answer» B. oxidation | |
| 404. |
If the energy gap of a semiconductor is 1.1 eV, then it would be |
| A. | opaque to visible light |
| B. | transparent to visible light |
| C. | transparent to ultraviolet radiation |
| D. | transparent to infrared radiation |
| Answer» B. transparent to visible light | |
| 405. |
The rate of change of excess carrier density is proportional to carrier density. |
| A. | 1 |
| B. | |
| C. | radio receivers |
| D. | public address system |
| Answer» B. | |
| 406. |
When a reverse bias is applied to a p-n junction, the width of depletion layer. |
| A. | decreases |
| B. | increases |
| C. | remains the same |
| D. | may increase or decrease |
| Answer» C. remains the same | |
| 407. |
In a bipolar transistor, emitter efficiency is about |
| A. | 0.99 |
| B. | 0.9 |
| C. | 0.8 |
| D. | 0.7 |
| Answer» B. 0.9 | |
| 408. |
Assertion (A): When reverse voltage across a p-n junction is increased, the junction capacitance decreases. Reason (R): Capacitance of any layer is inversely proportional to thickness. |
| A. | Both A and R are true and R is correct explanation of A |
| B. | Both A and R are true but R is not a correct explanation of A |
| C. | A is true but R is false |
| D. | A is false but R is true |
| Answer» B. Both A and R are true but R is not a correct explanation of A | |
| 409. |
For an insulating material, dielectric strength and dielectric loss should be respectively |
| A. | high and high |
| B. | low and high |
| C. | high and low |
| D. | low and low |
| Answer» D. low and low | |
| 410. |
In photoelectric emission the maximum kinetic energy of emitted electron is proportional to |
| A. | f2 |
| B. | f3 |
| Answer» C. | |
| 411. |
X-rays cannot penetrate through a thick sheet of |
| A. | wood |
| B. | paper |
| C. | lead |
| D. | aluminium |
| Answer» D. aluminium | |
| 412. |
What happens when forward bias is applied to a junction diode? |
| A. | Majority carrier current is reduced to zero |
| B. | Minority carrier current is reduced to zero |
| C. | Potential barrier is increased |
| D. | Potential barrier is decreased |
| Answer» E. | |
| 413. |
The carrier mobility in a semiconductor is 0.4 m2/Vs. Its diffusion constant at 300k will be (in m2/s). |
| A. | 0.43 |
| B. | 0.16 |
| C. | 0.04 |
| D. | 0.01 |
| Answer» C. 0.04 | |
| 414. |
The residual resistivity of a binary alloy at 0°K is |
| A. | the product of the residual resistivities of the component metals |
| B. | depend on the concentration of the minor component in the alloy |
| C. | Micanite |
| D. | Asbestos |
| Answer» E. | |
| 415. |
n channel FETs are better as compared to p-channel FET because |
| A. | they have higher input impedance |
| B. | mobility of electrons is more than that of holes |
| C. | lightly doped p substrate and highly doped n source and drain |
| D. | highly doped p substrate and highly doped n source and drain |
| Answer» E. | |
| 416. |
The concentration of minority carriers in an extrinsic semiconductor under equilibrium is |
| A. | directly proportional to the doping concentration |
| B. | inversely proportional to doping concentration |
| C. | directly proportional to intrinsic concentration |
| D. | inversely proportional to the intrinsic concentration |
| Answer» C. directly proportional to intrinsic concentration | |
| 417. |
The resistivity of ferrites is |
| A. | very much lower than that of the ferromagnetic metals |
| B. | slightly lower than that of the ferromagnetic materials |
| C. | slightly higher than that of the ferromagnetic metals |
| D. | very much higher than that of the ferromagnetic metals |
| Answer» E. | |
| 418. |
Indium, aluminium, arsenic are all p type impurities. |
| A. | additional holes are created in the conduction band |
| B. | protons get excited |
| C. | protons acquire charge |
| D. | energy of the atom is increased |
| Answer» C. protons acquire charge | |
| 419. |
The passage of current in an electrolyte is due to the movement of |
| A. | electrons |
| B. | molecules |
| C. | atoms |
| D. | ions |
| Answer» E. | |
| 420. |
Hall effect can be used to find the type of semiconductor. |
| A. | 1 |
| B. | |
| C. | 1 |
| D. | |
| Answer» B. | |
| 421. |
In a junction transistor, the collector cut-off current 'ICB0' reduces considerably by doping the |
| A. | emitter with high level of impurity |
| B. | emitter with low level of impurity |
| C. | collector with high level of impurity |
| D. | collector with low level of impurity |
| Answer» B. emitter with low level of impurity | |
| 422. |
Ferrites are |
| A. | hard materials |
| B. | brittle materials |
| C. | not easily machinable |
| D. | materials with all above properties |
| Answer» E. | |
| 423. |
In ferromagnetic materials |
| A. | the atomic magnetic moments are antiparallel and unequal |
| B. | the atomic magnetic moments are parallel |
| C. | the constituent is iron only |
| D. | one of the constituents is iron |
| Answer» C. the constituent is iron only | |
| 424. |
The channel of JFET consists of |
| A. | p type material only |
| B. | n type material only |
| C. | conducting material |
| D. | either p or n type material |
| Answer» E. | |
| 425. |
The reverse saturation current of a diode does not depend on temperature. |
| A. | 1 |
| B. | |
| C. | plastic deformation of the crystal |
| D. | magnetic Dipoles in the crystal |
| Answer» C. plastic deformation of the crystal | |
| 426. |
The on voltage and forward breakover voltage of an SCR depend on |
| A. | gate current alone |
| B. | band gap of semiconductor alone |
| C. | gate current and semiconductor band gap respectively |
| D. | semiconductor band gap and gate current respectively |
| Answer» E. | |
| 427. |
Which of the following can be operated with positive as well as negative gate voltage? |
| A. | JFET |
| B. | Both JFET and MOSFET |
| C. | MOSFET |
| D. | Neither JFET nor MOSFET |
| Answer» D. Neither JFET nor MOSFET | |
| 428. |
The forbidden energy gap for silicon is |
| A. | 0.12 eV |
| B. | 1.12 eV |
| C. | 0.72 eV |
| D. | 7.2 eV |
| Answer» C. 0.72 eV | |
| 429. |
Of the various capacitances associated with a junction transistor the gain bandwidth product is affected to maximum extend by |
| A. | base collector parasitic capacitor |
| B. | base collector space charge layer capacitance |
| C. | base emitter space charge layer capacitance |
| D. | base emitter diffusion capacitance |
| Answer» E. | |
| 430. |
Ohmic range of carbon composition resistors is |
| A. | 10 to 100 ohms |
| B. | 10 to 10 K ohms |
| C. | 10 to 200 ohms |
| D. | 10 to 25 M ohms |
| Answer» E. | |
| 431. |
Assertion (A): The hybrid p model of a transistor can be reduced to h parameter model and vice versa. Reason (R): Hybrid p and h parameter models are interrelated as both of them describe the same device. |
| A. | Both A and R are true and R is correct explanation of A |
| B. | Both A and R are true but R is not a correct explanation of A |
| C. | A is true but R is false |
| D. | A is false but R is true |
| Answer» B. Both A and R are true but R is not a correct explanation of A | |
| 432. |
For a P-N diode, the number of minority carriers crossing the junction depends on |
| A. | forward bias voltage |
| B. | potential barrier |
| C. | rate of thermal generation of electron hole pairs |
| D. | none of the above |
| Answer» D. none of the above | |
| 433. |
Ferrities are particularly suited for high frequency applications because of their |
| A. | low distortion |
| B. | low eddy current loss |
| C. | high conductivity |
| D. | high mobility |
| Answer» C. high conductivity | |
| 434. |
To avoid thermal runaway in the design of an analog circuit, the operating point of the BJT should be such that it satisfies the condition. |
| A. | VCE = VCC |
| B. | VCE ≤ VCC |
| C. | VCE ‚â• VCC |
| D. | VCE ≤ 0.78 VCC |
| Answer» C. VCE ‚â• VCC | |
| 435. |
An extrinsic semiconductor sample has 6 billion silicon atoms and 3 million pentavalent impurity atoms. The number of electrons and holes is |
| A. | 3 million each |
| B. | 6 billion each |
| C. | 3 million free electrons and very small number of holes |
| D. | 3 million holes and very small number of free electrons |
| Answer» D. 3 million holes and very small number of free electrons | |
| 436. |
In a centre tap full wave rectifier, 50 V is the peak voltage between the centre tap and one of the ends of the secondary. The maximum voltage across the reverse biased diode will be |
| A. | 100 V |
| B. | 72 V |
| C. | 50 V |
| D. | 38 V |
| Answer» B. 72 V | |
| 437. |
The SCR would be turned OFF by voltage reversal of applied anode-cathode ac supply of frequency of |
| A. | 30 kHz |
| B. | 15 kHz |
| C. | 5 kHz |
| D. | 20 kHz |
| Answer» D. 20 kHz | |
| 438. |
In commercial electron tubes the current produced by the cathode at 1000 K is about |
| A. | 0.01 A per cm2 of cathode surface |
| B. | 0.1 A per cm2 of cathode surface |
| C. | 1 A per cm2 of cathode surface |
| D. | 5 A per cm2 of cathode surface |
| Answer» C. 1 A per cm2 of cathode surface | |
| 439. |
As temperature increases the number of free electrons and holes in an intrinsic semiconductor |
| A. | increases |
| B. | decreases |
| C. | remains the same |
| D. | may increase or decrease |
| Answer» B. decreases | |
| 440. |
If for a silicon n-p-n transistor, the base to emitter voltage (VBE) is 0.7 V and the collector to base voltage VCB is 0.2 Volt, then the transistor is operating in the |
| A. | normal active mode |
| B. | saturation mode |
| C. | inverse active mode |
| D. | cut off mode |
| Answer» B. saturation mode | |
| 441. |
If the conductivity of pure germanium is 1.54 siemens/metre, its resistivity in ohm-metre will be nearly |
| A. | 65 |
| B. | 6.5 |
| C. | 0.65 |
| D. | 0.065 |
| Answer» C. 0.65 | |
| 442. |
Assertion (A): In a BJT, adc is about 0.98. Reason (R): In a BJT, recombination in base region is high. |
| A. | Both A and R are true and R is correct explanation of A |
| B. | Both A and R are true but R is not a correct explanation of A |
| C. | A is true but R is false |
| D. | A is false but R is true |
| Answer» B. Both A and R are true but R is not a correct explanation of A | |
| 443. |
At room temperature the barrier potential in a silicon diode is |
| A. | 0.1 V |
| B. | 0.3 V |
| C. | 0.7 V |
| D. | 1 V |
| Answer» D. 1 V | |
| 444. |
The output, V-I characteristics of an Enhancement type MOSFET has |
| A. | only an ohmic region |
| B. | only a saturation region |
| C. | an ohmic region at low voltage value followed by a saturation region at higher voltages |
| D. | an ohmic region at large voltage values preceded by a saturation region at lower voltages |
| Answer» D. an ohmic region at large voltage values preceded by a saturation region at lower voltages | |
| 445. |
Which of the following is anti-ferromagnetic material? |
| A. | CrSb |
| B. | NIO |
| C. | MnO |
| D. | All of the above |
| Answer» E. | |
| 446. |
n-type semiconductors |
| A. | are negatively charged |
| B. | are produced when indium is added as impurity to germanium |
| C. | are produced when phosphorus is added as impurity to silicon |
| D. | none of the above |
| Answer» D. none of the above | |
| 447. |
The emission of light is LED due to |
| A. | emission of holes |
| B. | emission of electrons |
| C. | generation of electromagnetic radiations |
| D. | conversion of heat energy into illumination |
| Answer» D. conversion of heat energy into illumination | |
| 448. |
The modulation of effective base width by collector voltage is known as Early effect, hence reverse collector voltage |
| A. | increases both a and β |
| B. | decrease both a and β |
| C. | increase a but decrease β |
| D. | decrease a but increase β |
| Answer» D. decrease a but increase Œ≤ | |
| 449. |
Assertion (A): A p-n junction is used as rectifier. Reason (R): A p-n junction has low resistance in forward direction and high resistance in reverse direction. |
| A. | Both A and R are true and R is correct explanation of A |
| B. | Both A and R are true but R is not a correct explanation of A |
| C. | A is true but R is false |
| D. | A is false but R is true |
| Answer» B. Both A and R are true but R is not a correct explanation of A | |
| 450. |
The thermionic emission current is given by |
| A. | Richardson Dushman equation |
| B. | Langmuir Child law |
| C. | both junctions are forward biased |
| D. | both junctions are reverse biased |
| Answer» D. both junctions are reverse biased | |