MCQOPTIONS
Saved Bookmarks
MCQOPTIONS
This section includes 869 Mcqs, each offering curated multiple-choice questions to sharpen your BITSAT knowledge and support exam preparation. Choose a topic below to get started.
| 551. |
The ripple factor from a capacitor filter __________ as the load resistance __________ . |
| A. | decreases, decreases |
| B. | decreases, increases |
| C. | increases, decreases |
| D. | increases, increases |
| Answer» C. increases, decreases | |
| 552. |
In intrinsic semiconductor at 300 K, the magnitude of free electron concentration in silicon is about |
| A. | 15 x 10⁴ per cm³ |
| B. | 5 x 10¹² per cm³ |
| C. | 1.45 x 10¹ᴼ per cm³ |
| D. | 1.45 x 10⁶ per cm³ |
| Answer» D. 1.45 x 10⁶ per cm³ | |
| 553. |
Indium, aluminium, arsenic are all p type impurities. |
| A. | True |
| B. | False |
| C. | May be True or False |
| D. | Can't say |
| Answer» C. May be True or False | |
| 554. |
In a reverse biased P-N junction, the current through the junction increases abruptly at |
| A. | zero voltage |
| B. | 1.2 V |
| C. | 0.72 V |
| D. | breakdown voltage |
| Answer» E. | |
| 555. |
The ripple factor for a bridge rectifier is |
| A. | 0.406 |
| B. | 1.21 |
| C. | 1.11 |
| D. | 2.22 |
| Answer» C. 1.11 | |
| 556. |
Piezoelectric quartz crystal resonators find application where |
| A. | signal amplification is required |
| B. | rectification of the signal is required |
| C. | signal frequency control is required |
| D. | modulation of signal is required |
| Answer» C. signal frequency control is required | |
| 557. |
An n type semiconductor is illuminated by a steady flux of photons with energy greater than the band gap energy. The change in conductivity Δσ obeys which relation? [ Here, e is the electron charge, μn electron mobility, μp hole mobility, Δn (Δp) is the excess electron (hole) density ]. |
| A. | Δσ = 0 |
| B. | Δσ = e(σn + σp) Δn |
| C. | Δσ = e(μnΔn - μpΔp) |
| D. | Δσ = e μnΔn |
| Answer» C. Δσ = e(μnΔn - μpΔp) | |
| 558. |
Dynamic resistance of diode is dv/di |
| A. | True |
| B. | False |
| C. | May be True or False |
| D. | Can't say |
| Answer» B. False | |
| 559. |
Electromagnetic waves transport |
| A. | energy only |
| B. | momentum only |
| C. | energy as well as momentum |
| D. | neither energy nor momentum |
| Answer» D. neither energy nor momentum | |
| 560. |
In which condition does BJT behave like a closed switch? |
| A. | Cut off |
| B. | Saturation |
| C. | Forward active |
| D. | Reverse active |
| Answer» C. Forward active | |
| 561. |
The atomic weight of an atom is determined by |
| A. | the number of protons |
| B. | the number of neutrons |
| C. | the number of protons and neutrons |
| D. | the number of electrons and protons |
| Answer» D. the number of electrons and protons | |
| 562. |
The relation between thermionic emission current and temperature is known as |
| A. | Richardson Dushman equation |
| B. | Langmuir child law |
| C. | Ohm's law |
| D. | Boltzmann's law |
| Answer» B. Langmuir child law | |
| 563. |
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 | |
| 564. |
Assertion (A): When a high reverse voltage is applied to a p-n junction the diode breaks down.Reason (R): High reverse voltage causes Avalanche effect. |
| 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 | |
| 565. |
In monostable multivibrator |
| A. | has no stable state |
| B. | has one stable state |
| C. | has two stable states |
| D. | switches automatically from one state to other state |
| Answer» C. has two stable states | |
| 566. |
In a vacuum triode μ = rpgm. |
| A. | True |
| B. | False |
| C. | May be True or False |
| D. | Can't say |
| Answer» B. False | |
| 567. |
If the gate of JFET is reverse biased, the width of depletion region |
| A. | becomes zero |
| B. | is uniform |
| C. | is more near the source |
| D. | is more near the drain |
| Answer» E. | |
| 568. |
The potential of suppressor grid (with respect to cathode) is usually |
| A. | zero |
| B. | negative |
| C. | positive |
| D. | zero or positive |
| Answer» B. negative | |
| 569. |
Before doping the semiconductor material is |
| A. | dehydrated |
| B. | heated |
| C. | hardened |
| D. | purified |
| Answer» E. | |
| 570. |
Resistivity of electrical conductors is most affected by |
| A. | Pressure |
| B. | temperature |
| C. | composition |
| D. | ageing |
| Answer» C. composition | |
| 571. |
The maximum forward current in case of signal diode is in the range of |
| A. | 1 A to 10 A |
| B. | 0.1 A to 1 A |
| C. | few milli amperes |
| D. | few nano amperes |
| Answer» D. few nano amperes | |
| 572. |
The phenomenon known as "Early effect" in a BJT refers to a reduction of the effective base width caused by |
| A. | electron-hole recombination at the base |
| B. | reverse biasing of the base collector junction |
| C. | forward biasing of emitter base junction |
| D. | the early removal of stored base charge during saturation to cut off switching |
| Answer» C. forward biasing of emitter base junction | |
| 573. |
Which of the following semi-conductor has forbidden energy gap less 1 eV? |
| A. | Sulphur |
| B. | Phosphorous |
| C. | Germanium |
| D. | Carbon |
| Answer» D. Carbon | |
| 574. |
The value of α in a transistor |
| A. | is always equal to 1 |
| B. | is less than 1 but more than 0.9 |
| C. | is about 0.4 |
| D. | is about 0.1 |
| Answer» C. is about 0.4 | |
| 575. |
The intrinsic resistivity of silicon at 300 K is about |
| A. | 1 Ω-cm |
| B. | 400 Ω-cm |
| C. | 10000 Ω-cm |
| D. | 230000 Ω-cm |
| Answer» E. | |
| 576. |
For a photoengraving the mask used is |
| A. | master mask |
| B. | slave mask |
| C. | working mask |
| D. | photo mask |
| Answer» D. photo mask | |
| 577. |
If the drift velocity of holes under a field gradient of 100 V/m in 5 m/s, their mobility (in SI units) is |
| A. | 0.05 |
| B. | 0.5 |
| C. | 50 |
| D. | 500 |
| Answer» B. 0.5 | |
| 578. |
X-rays cannot penetrate through a thick sheet of |
| A. | wood |
| B. | paper |
| C. | lead |
| D. | aluminium |
| Answer» D. aluminium | |
| 579. |
For a NPN bipolar transistor, what is the main stream of current in the base region? |
| A. | Drift of holes |
| B. | Diffusion of holes |
| C. | Drift of electrons |
| D. | Diffusion of electrons |
| Answer» C. Drift of electrons | |
| 580. |
Which one of the following is not a characteristic of a ferroelectric material? |
| A. | High dielectric constant |
| B. | No hysteresis |
| C. | Ferroelectric characteristic only above the curie point |
| D. | Electric dipole moment |
| Answer» D. Electric dipole moment | |
| 581. |
Assertion (A): A VMOS can handle much larger current than other field effect transistors.Reason (R): In a VMOS the conducting channel is very narrow. |
| 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» D. A is false but R is true | |
| 582. |
The most commonly used semiconductor material is |
| A. | silicon |
| B. | germanium |
| C. | mixture of silicon and germanium |
| D. | none of the above |
| Answer» B. germanium | |
| 583. |
A transistor has a current gain of 0.99 in the CB mode. Its current gain in the CC mode is |
| A. | 100 |
| B. | 99 |
| C. | 1.01 |
| D. | 0.99 |
| Answer» B. 99 | |
| 584. |
In which of these is reverse recovery time nearly zero? |
| A. | Zener diode |
| B. | Tunnel diode |
| C. | Schottky diode |
| D. | PIN diode |
| Answer» D. PIN diode | |
| 585. |
Work function is the maximum energy required by the fastest electron at 0 K to escape from the metal surface. |
| A. | True |
| B. | False |
| C. | May be True or False |
| D. | Can't say |
| Answer» C. May be True or False | |
| 586. |
At room temperature the current in an intrinsic semiconductor is due to |
| A. | holes |
| B. | electrons |
| C. | ions |
| D. | holes and electrons |
| Answer» E. | |
| 587. |
A p-n junction diode has |
| A. | low forward and high reverse resistance |
| B. | a non-linear v-i characteristics |
| C. | zero forward current till the forward voltage reaches cut in value |
| D. | all of the above |
| Answer» E. | |
| 588. |
The minority carrier life time and diffusion constant in a semiconductor material are respectively 100 microsecond and 100 cm²/sec. The diffusion length is |
| A. | 0.1 cm |
| B. | 0.01 cm |
| C. | 0.0141 cm |
| D. | 1 cm |
| Answer» B. 0.01 cm | |
| 589. |
The power dissipation in a transistor is the product of |
| A. | emitter current and emitter to base voltage |
| B. | emitter current and collector to emitter voltage |
| C. | collector current and collector to emitter voltage |
| D. | none of the above |
| Answer» D. none of the above | |
| 590. |
Which of the following is true as regards photo emission? |
| A. | Velocity of emitted electrons is dependent on light intensity |
| B. | Rate of photo emission is inversely proportional to light intensity |
| C. | Maximum velocity of electron increases with decreasing wave length |
| D. | Both holes and electrons are produced |
| Answer» D. Both holes and electrons are produced | |
| 591. |
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 | |
| 592. |
Holes act like |
| A. | positive charges |
| B. | neutral atoms |
| C. | negative charges |
| D. | crystals |
| Answer» B. neutral atoms | |
| 593. |
A zener diode is used in |
| A. | voltage regulator circuit |
| B. | amplifier circuits |
| C. | both voltage regulator and amplifier circuit |
| D. | none of the above |
| Answer» B. amplifier circuits | |
| 594. |
The modulation of effective base width by collector voltage is known as Early effect, hence reverse collector voltage |
| A. | increases both α and β |
| B. | decrease both α and β |
| C. | increase α but decrease β |
| D. | decrease α but increase β |
| Answer» D. decrease α but increase β | |
| 595. |
A P-N junction offers |
| A. | high resistance in forward as well as reverse direction |
| B. | low resistance in forward as well as reverse direction |
| C. | conducts in forward direction only |
| D. | conducts in reverse direction only |
| Answer» D. conducts in reverse direction only | |
| 596. |
The current gain of a bipolar transistor drops at high frequencies because of |
| A. | transistor capacitance |
| B. | high current effects in the base |
| C. | parasitic inductive elements |
| D. | the early effect |
| Answer» B. high current effects in the base | |
| 597. |
In a p-n-p transistor operating in forward active mode |
| A. | base is positive with respect to emitter and collector |
| B. | base is negative with respect to emitter and collector |
| C. | emitter is positive with respect to base and base is positive with respect to collector |
| D. | emitter is negative with respect to base and base is positive with respect to collector |
| Answer» D. emitter is negative with respect to base and base is positive with respect to collector | |
| 598. |
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 | |
| 599. |
Assertion (A): The forward resistance of a p-n diode is not constant.Reason (R): The v-i characteristics of p-n diode is non-linear. |
| 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 | |
| 600. |
Transconductance indicates the |
| A. | control of output voltage by input voltage |
| B. | control of output current by input voltage |
| C. | control of input voltage by output current |
| D. | control of input current by input voltage |
| Answer» C. control of input voltage by output current | |