MCQOPTIONS
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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.
| 601. |
When a ferromagnetic substance is magnetised, there are small changes in its dimensions. This phenomenon is called |
| A. | hysteresis |
| B. | magnetostriction |
| C. | diamagnetism |
| D. | bipolar relaxation |
| Answer» C. diamagnetism | |
| 602. |
Assertion (A): At room temperature the fermi level in p type semiconductor lies nearer to the valence band and in n type semiconductor it lies nearer to the conduction band.Reason (R): At room temperature, the p type semiconductor is rich in holes and n type semiconductor is rich in electrons. |
| 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 | |
| 603. |
Under low level injection assumption, the infected minority carrier current for an extrinsic semiconductor is essentially the |
| A. | diffusion current |
| B. | drift current |
| C. | recombination current |
| D. | induced current |
| Answer» B. drift current | |
| 604. |
For a photo conductor with equal electron and hole mobilities and perfect ohmic contacts at the ends, an increase in the intensities of optical illumination results in |
| A. | change in open circuit voltage |
| B. | change in short circuit current |
| C. | a reduction resistance |
| D. | an increase of resistance |
| Answer» D. an increase of resistance | |
| 605. |
Mobility of electrons and holes are equal. |
| A. | True |
| B. | False |
| C. | May be True or False |
| D. | Can't say |
| Answer» C. May be True or False | |
| 606. |
The forbidden energy gap between the valence band and conduction band will be wide in case of |
| A. | semiconductors |
| B. | all metals |
| C. | good conductors of electricity |
| D. | insulators |
| Answer» E. | |
| 607. |
Consider the following statement S1 and S2. S1: The β of a bipolar transistor reduces if the base width is increased. S2: the β of a bipolar transistor increases if the doping concentration in the base is increased. Which one of the following is correct? |
| A. | S1 is False, S2 is true |
| B. | S1 and S2 both are true |
| C. | S1 and S2 both are false |
| D. | S1 is true, S2 is false |
| Answer» E. | |
| 608. |
In a photo emissive device and emission efficiency is increased by |
| A. | coating the cathode ray by an active materials |
| B. | coating the cathode by an insulating material |
| C. | heating the cathode |
| D. | cooling the anode |
| Answer» B. coating the cathode by an insulating material | |
| 609. |
The primary reason for the widespread use of Si in semiconductor device technology is |
| A. | abundance of Si on the surface of earth |
| B. | larger band gap of Si in comparison to Ge |
| C. | favourable properties of Silicon-dioxide (SiO₂) |
| D. | lower melting point |
| Answer» D. lower melting point | |
| 610. |
An incremental model of a solid state device is one which represents the |
| A. | ac property of the device at desired operating point |
| B. | dc property of the device at all operating points |
| C. | complete ac and dc behaviour at all operating points |
| D. | ac property of the device at all operating points |
| Answer» B. dc property of the device at all operating points | |
| 611. |
Assertion (A): When a photoconductive device is exposed to light, its bulk resistance increases.Reason (R): When exposed to light, electron hole pairs are generated in the photoconductive 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» E. | |
| 612. |
The skin depth of copper is found to be 66 mm at 1 MHz at a certain temperature. At the same temperature and at 2 MHz, the skin depth would be approximately |
| A. | 47 μm |
| B. | 33 μm |
| C. | 92 μm |
| D. | 1.22 μm |
| Answer» B. 33 μm | |
| 613. |
Highest resistivity of the following is |
| A. | nichrome |
| B. | constantan |
| C. | metal |
| D. | manganin |
| Answer» B. constantan | |
| 614. |
Which of the following devices has a silicon dioxide layer? |
| A. | NPN transistor |
| B. | Tunnel diode |
| C. | JFET |
| D. | MOSFET |
| Answer» E. | |
| 615. |
Gold is often diffused into silicon P-N junction devices to |
| A. | increase recombination rate |
| B. | reduce recombination rate |
| C. | make silicon a direct gap semiconductor |
| D. | make silicon semimetal |
| Answer» C. make silicon a direct gap semiconductor | |
| 616. |
The scaling factor of an MOS device using constant voltage scaling model, the gate area of the device will be scaled as |
| A. | 1/α |
| B. | 1/α² |
| C. | 1/α³ |
| D. | 1/α⁴ |
| Answer» E. | |
| 617. |
In monolithic ICs, all the components are fabricated by |
| A. | diffusion process |
| B. | oxidation |
| C. | evaporation |
| D. | none |
| Answer» B. oxidation | |
| 618. |
Wienbridge oscillator uses |
| A. | -ve feedback |
| B. | +ve feedback |
| C. | both +ve, -ve feedback |
| D. | feedback is not required |
| Answer» D. feedback is not required | |
| 619. |
When a p-n Junction is forward biased |
| A. | the current flow is due to electrons only |
| B. | the majority carriers in both p and n materials are driven toward the junction. |
| C. | the majority carriers in both p and n materials are away from the junction. |
| D. | both (a) and (c). |
| Answer» C. the majority carriers in both p and n materials are away from the junction. | |
| 620. |
Given that the band gap of cadmium sulphide is 2.5 eV, the maximum photon wavelength, for e¯-hole pair generation will be |
| A. | 5400 mm |
| B. | 540 mm |
| C. | 5400 Å |
| D. | 540 Å |
| Answer» D. 540 Å | |
| 621. |
The sum of two or more arbitrary sinusoidal is |
| A. | always periodic |
| B. | periodic under certain conditions |
| C. | never periodic |
| D. | periodic only if all the sinusoidals are identical in frequency and phase |
| Answer» E. | |
| 622. |
The dynamic resistance of a forward biased p-n diode |
| A. | varies inversely with current |
| B. | varies directly with current |
| C. | is constant |
| D. | is either constant or varies directly with current |
| Answer» B. varies directly with current | |
| 623. |
In case of photo conductor for germanium when forbidden energy gap is 0.72 eV, the critical wavelength for intrinsic excitation will be |
| A. | 1.43 m |
| B. | 1.43 mm |
| C. | 1.73 mm |
| D. | 1.73 x 10¹² m |
| Answer» D. 1.73 x 10¹² m | |
| 624. |
Holes and electrons move in opposite directions. |
| A. | True |
| B. | False |
| C. | May be True or False |
| D. | Can't say |
| Answer» B. False | |
| 625. |
The depletion layer width of Junction |
| A. | decreases with light doping |
| B. | is independent of applied voltage |
| C. | is increased under reverse bias |
| D. | increases with heavy doping |
| Answer» D. increases with heavy doping | |
| 626. |
Forbidden energy gap in germanium at 0 K is about |
| A. | 10 eV |
| B. | 5 eV |
| C. | 2 eV |
| D. | 0.78 eV |
| Answer» E. | |
| 627. |
The inductance of a single layer solenoid of 10 turns is 5 μH. Which one of the following is the correct value of inductance when the number of turns is 20 and the length is doubled. |
| A. | 10 μH |
| B. | 20 μH |
| C. | 40 μH |
| D. | 5 μH |
| Answer» B. 20 μH | |
| 628. |
Power diodes are generally |
| A. | silicon diodes |
| B. | germanium diodes |
| C. | either of the above |
| D. | none of the above |
| Answer» B. germanium diodes | |
| 629. |
To produce p type semiconductor we add |
| A. | acceptor atoms |
| B. | donor atoms |
| C. | pentavalent impurity |
| D. | trivalent impurity |
| Answer» E. | |
| 630. |
Voltage series feedback (Also called series-shunt feedback) results in |
| A. | increase in both I/P and O/P impedances |
| B. | decrease in both I/P and O/P impedances |
| C. | increase in I/P impedance and decrease in O/P impedance |
| D. | decrease in I/P impedance and increase in O/P impedance |
| Answer» D. decrease in I/P impedance and increase in O/P impedance | |
| 631. |
Which of the following has highest resistivity? |
| A. | Mica |
| B. | Paraffin wax |
| C. | Air |
| D. | Mineral oil |
| Answer» D. Mineral oil | |
| 632. |
Assertion (A): In p-n-p transistor collector current is termed negative.Reason (R): In p-n-p transistor holes are majority carriers. |
| 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» C. A is true but R is false | |
| 633. |
The addition of p type impurity to intrinsic material creates allowable energy levels. |
| A. | slightly below conduction band |
| B. | slightly above conduction band |
| C. | slightly below valence band |
| D. | slightly above valence band |
| Answer» E. | |
| 634. |
An ideal Op-amp is an ideal |
| A. | voltage controlled current source |
| B. | voltage controlled voltage source |
| C. | current controlled current source |
| D. | current controlled voltage source |
| Answer» C. current controlled current source | |
| 635. |
Maximum rectification efficiency for a half wave rectifier is |
| A. | 100% |
| B. | 88% |
| C. | 50% |
| D. | 40.6% |
| Answer» E. | |
| 636. |
Free electrons exist in |
| A. | first band |
| B. | second band |
| C. | third band |
| D. | conduction band |
| Answer» E. | |
| 637. |
Resistivity of copper is nearly |
| A. | 1.56 μ ohm-cm |
| B. | 3.95 μ ohm-cm |
| C. | 14.55 μ ohm-cm |
| D. | 22.05 μ ohm-cm |
| Answer» B. 3.95 μ ohm-cm | |
| 638. |
An intrinsic silicon sample has 1 million free electrons at room temperature. As the temperature is increased |
| A. | the number of free electrons increases |
| B. | the number of free electrons increases but the number of holes decreases |
| C. | the number of free electrons and holes increase by the same amount |
| D. | the number of free electrons and holes increase but not by the same amount |
| Answer» D. the number of free electrons and holes increase but not by the same amount | |
| 639. |
What is the necessary a.c. input power from the transformer secondary used in a half wave rectifier to deliver 500 W of d.c. power to the load? |
| A. | 1232 W |
| B. | 848 W |
| C. | 616 W |
| D. | 308 W |
| Answer» B. 848 W | |
| 640. |
In a half wave rectifier, the load current flows |
| A. | only for the positive half cycle of the input signal |
| B. | only for the negative half cycle of the input signal |
| C. | for full cycle |
| D. | for less than fourth cycle |
| Answer» B. only for the negative half cycle of the input signal | |
| 641. |
The term efficacy, is defined by |
| A. | same as efficiency |
| B. | measure of the ability of a device to produce a desired effect |
| C. | input/output |
| D. | (efficiency)² |
| Answer» C. input/output | |
| 642. |
A Schottky diode clamp is used along with a switching BJT for |
| A. | reducing the power |
| B. | reducing the switching time dissipation |
| C. | increasing the value of β |
| D. | reducing the base current |
| Answer» C. increasing the value of β | |
| 643. |
The first dominant pole encountered in the frequency response of a compensated op-amp is approximately at |
| A. | 5 Hz |
| B. | 10 kHz |
| C. | 1 MHz |
| D. | 100 MHz |
| Answer» B. 10 kHz | |
| 644. |
As compared to bipolar junction transistor, a FET |
| A. | is less noisy |
| B. | has better thermal stability |
| C. | has higher input resistance |
| D. | all of the above |
| Answer» E. | |
| 645. |
For a semiconductor, the conductivity is a function of the products of the number of charge carriers and their mobilites. As result, if the temperature of a slab of intrinsic silicon increases, how does its conductivity vary? |
| A. | Decreases |
| B. | Increases |
| C. | Remains unaffected |
| D. | Increases or decreases depending upon the rise in temperature |
| Answer» C. Remains unaffected | |
| 646. |
Silicon is not suitable for fabrication of light emitting diodes because it is |
| A. | an indirect band gap semiconductor |
| B. | direct band gap semiconductor |
| C. | wideband gap semiconductor |
| D. | narrowband gap semiconductor |
| Answer» B. direct band gap semiconductor | |
| 647. |
MOSFET can be used as a |
| A. | current controlled capacitor |
| B. | voltage controlled capacitor |
| C. | current controlled inductor |
| D. | voltage controlled inductor |
| Answer» C. current controlled inductor | |
| 648. |
Hall effect is observed in a specimen when it is carrying current and is placed in a magnetic field. The resultant electric field inside the specimen is |
| A. | normal to both current and magnetic field |
| B. | in the direction of current |
| C. | antiparallel to magnetic field |
| D. | in arbitrary direction |
| Answer» B. in the direction of current | |
| 649. |
The effect of current shunt feedback in an amplifier is to |
| A. | increase the I/P resistance and decrease the O/P resistance |
| B. | increase both I/P and O/P resistance |
| C. | decrease both I/P and O/P resistance |
| D. | decrease the I/P resistance and increase O/P resistance |
| Answer» E. | |
| 650. |
In the sale of diamonds the unit of weight is carat. One carat is equal to |
| A. | 100 mg |
| B. | 150 mg |
| C. | 200 mg |
| D. | 500 mg |
| Answer» D. 500 mg | |