MCQOPTIONS
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MCQOPTIONS
This section includes 142 Mcqs, each offering curated multiple-choice questions to sharpen your Engineering Physics knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
What type of material is obtained when an intrinsic semiconductor is doped with trivalent impurity? |
| A. | Extrinsic semiconductor |
| B. | Insulator |
| C. | N-type semiconductor |
| D. | P-type semiconductor |
| Answer» E. | |
| 2. |
What type of material is obtained when an intrinsic semiconductor is doped with pentavalent impurity? |
| A. | N-type semiconductor |
| B. | Extrinsic semiconductor |
| C. | P-type semiconductor |
| D. | Insulator |
| Answer» B. Extrinsic semiconductor | |
| 3. |
How are charge carriers produced in intrinsic semiconductors? |
| A. | By pure atoms |
| B. | By electrons |
| C. | By impure atoms |
| D. | By holes |
| Answer» D. By holes | |
| 4. |
How does a semiconductor behave at absolute zero? |
| A. | Conductor |
| B. | Insulator |
| C. | Semiconductor |
| D. | Protection device |
| Answer» C. Semiconductor | |
| 5. |
Dielectric breakdown occurs when _____ |
| A. | Dielectric physically breaks down |
| B. | It attains high resistivity |
| C. | It starts conducting |
| D. | It comes in contact with another potential dielectric |
| Answer» D. It comes in contact with another potential dielectric | |
| 6. |
In a vacuum tetrode, secondary emission is because of emission of _____. |
| A. | electrons from the filament due to heat energy |
| B. | high velocity electrons from the cathode |
| C. | electrons from the plate due to the bombardment of the fast-moving electrons emitted from the cathode |
| D. | electrons belonging to the second orbit of the atoms of cathode |
| Answer» D. electrons belonging to the second orbit of the atoms of cathode | |
| 7. |
In the case of the p - n junction diode, at a high value of reverse bias, the current rises sharply. The value of reverse voltage is known as |
| A. | Cut in voltage |
| B. | Break-down voltage |
| C. | Cut off voltage |
| D. | Inverse voltage |
| Answer» C. Cut off voltage | |
| 8. |
In an AC circuit, SCR works like a _____ |
| A. | transistor |
| B. | alternator |
| C. | full wave rectifier |
| D. | half wave rectifier |
| Answer» E. | |
| 9. |
In a transistor the ___________ is very thin and lightly doped. |
| A. | emitter |
| B. | base |
| C. | junction |
| D. | collector |
| Answer» C. junction | |
| 10. |
Light of frequency 2 × 1014 Hz is same as light of wavelength _________. |
| A. | 1.5 μm |
| B. | 150 μm |
| C. | 5 × 10-13m |
| D. | 1.5 × 10-13m |
| Answer» B. 150 μm | |
| 11. |
Germanium is a commonly used ______. |
| A. | Moderator |
| B. | Semiconductor |
| C. | Conductor |
| D. | Insulator |
| Answer» C. Conductor | |
| 12. |
Probability of energy state EF (Fermi Level) occupied by an electron at absolute temperature can be approximated as ________ |
| A. | 0.5 |
| B. | 0 |
| C. | 0.25 |
| D. | 1 |
| Answer» E. | |
| 13. |
A good insulating material should have _________ dielectric strength and _________ dielectric loss? |
| A. | Low, Low |
| B. | High, High |
| C. | Low, High |
| D. | High, Low |
| Answer» E. | |
| 14. |
HEMT used in microwave circuit is a |
| A. | source |
| B. | high power amplifier |
| C. | low noise amplifier |
| D. | detector |
| Answer» D. detector | |
| 15. |
In the given circuit, the current through Zener diode is close to |
| A. | 6.0 mA |
| B. | 6.7 mA |
| C. | 0 mA |
| D. | 4.0 mA |
| Answer» D. 4.0 mA | |
| 16. |
Doping intrinsic Silicon with Arsenic as an impurity |
| A. | Only increases the conductivity of Silicon by increasing the number of free electrons available |
| B. | Produces a semi-conductor in which the charge carriers are predominantly electrons but holes are also present |
| C. | Produces a semi-conductor in which the charge carriers are predominantly holes but free electrons also present |
| D. | Produces a semi-conductor in which the charge carriers contain nearly equal number of electrons and holes |
| Answer» B. Produces a semi-conductor in which the charge carriers are predominantly electrons but holes are also present | |
| 17. |
Ge and Si diodes start conducting at 0.3 V and 0.7 V respectively. In the following figure if Ge diode connection are reversed, the value of Vo changes by:(Assume that the Ge diode has large breakdown voltage) |
| A. | 0.8 V |
| B. | 0.6 V |
| C. | 0.2 V |
| D. | 0.4 V |
| Answer» E. | |
| 18. |
Maximum energy of electron liberated photoelectrically is : |
| A. | proportional to light intensity and independent of frequency of light |
| B. | Independent of light intensity and varies linearly with frequency of the light |
| C. | Proportional to both, light intensity and frequency of light |
| D. | Independent of light intensity and inversely proportional to frequency of the light |
| Answer» C. Proportional to both, light intensity and frequency of light | |
| 19. |
For a transistor in common emitter configuration _______________ is the ratio of change in collector-emitter voltage (ΔVCE) to the change in collector current (ΔIC) at a constant base current 'IB'. |
| A. | Output resistance |
| B. | Input resistance |
| C. | Current amplification factor |
| D. | Voltage gain |
| Answer» B. Input resistance | |
| 20. |
In case of semi-conductors, the ratio of conduction current to displacement current is: |
| A. | more than 200 and less than 1000 |
| B. | less than 100 but greater than 1/100 |
| C. | less than 1/100 |
| D. | more than 1000 |
| Answer» C. less than 1/100 | |
| 21. |
LED is a p-n junction diode which is |
| A. | Forward biased |
| B. | Either forward biased or reverse biased |
| C. | Reverse biased |
| D. | Neither forward biased nor reverse biased |
| Answer» B. Either forward biased or reverse biased | |
| 22. |
in Ge, when atoms are held together by the sharing of valence electrons __________. |
| A. | Each shared atom leaves a hole |
| B. | valence electrons are free to move away from the nucleus |
| C. | valence electrons form irreversible covalent bands |
| D. | valence electrons form reversible covalent bands |
| Answer» E. | |
| 23. |
N – type silicon is obtained by doping silicon with |
| A. | Germanium |
| B. | Aluminium |
| C. | Boron |
| D. | Phosphorus |
| Answer» E. | |
| 24. |
For given circuit, the forward resistance of p-n junction is 50 Ω and reverse resistance is infinite. Then current flowing through 100 Ω resistance is |
| A. | 0.01 A |
| B. | 0.02 A |
| C. | 0.024 A |
| D. | 0.04 A |
| Answer» C. 0.024 A | |
| 25. |
A good silicon APD has a capacitance of 5pF, with negligible dark current and is operating with a post-detection bandwidth of 50 MHz. The photocurrent before gain is given by 10−7 Amp. The operating temperature is 188C. The value of Load resistor to be connected with APD is given by: |
| A. | 536.5 ohm |
| B. | 635.5 ohm |
| C. | 835.5 ohm |
| D. | 83.5 ohm |
| Answer» C. 835.5 ohm | |
| 26. |
For a three-layer stranded wire, the number of strands in first, second and third layer respectively are: |
| A. | 1, 4 and 8 |
| B. | 1, 6 and 12 |
| C. | 1, 5 and 10 |
| D. | 1, 7 and 14 |
| Answer» C. 1, 5 and 10 | |
| 27. |
An example for semiconductor |
| A. | Copper |
| B. | Aluminium |
| C. | Mica |
| D. | Germanium |
| Answer» E. | |
| 28. |
Assertion A: Si can be operated at high temperatureReason R: Energy gap of Ge is more than Si |
| A. | A is correct but R is not correct |
| B. | A is correct but R is not a suitable reason for it |
| C. | A is correct and R is the suitable reason for it |
| D. | R is correct but A is not correct |
| Answer» B. A is correct but R is not a suitable reason for it | |
| 29. |
Metals are ________. |
| A. | Transparent |
| B. | Opaque |
| C. | Translucent |
| D. | None |
| Answer» C. Translucent | |
| 30. |
Number of electrons in the outer orbit of Ge |
| A. | 4 |
| B. | 8 |
| C. | 7 |
| D. | 1 |
| Answer» B. 8 | |
| 31. |
One kg of water, at 20°C, is heated in an electric kettle whose heating element has a mean (temperature averaged) resistance of 20Ω. The rms voltage in the mains is 200 V. Ignoring heat loss from the kettle, time taken for water to evaporate fully, is close to:[Specific heat of water = 4200 J/(kg° C) and Latent heat of water = 2260 kJ/kg] |
| A. | 16 minutes |
| B. | 22 minutes |
| C. | 3 minutes |
| D. | 10 minutes |
| Answer» C. 3 minutes | |
| 32. |
An element whose atoms have three valance electrons, the example of such element is |
| A. | Silicon |
| B. | Copper |
| C. | Germanium |
| D. | Aluminum |
| Answer» E. | |
| 33. |
Imperfections in the crystal structure result in __________. |
| A. | increased conductivity |
| B. | decreased conductivity |
| C. | increased mobility |
| D. | decreased mobility |
| Answer» E. | |
| 34. |
Figure shows a DC voltage regulator circuit, with a Zener diode of breakdown voltage = 6 V. If the unregulated input voltage varies between 10 V to 16 V, then what is the maximum Zener current? |
| A. | 2.5 mA |
| B. | 1.5 mA |
| C. | 7.5 mA |
| D. | 3.5 mA |
| Answer» E. | |
| 35. |
In a reflex klystron, the velocity modulation |
| A. | Occurs near the reflector |
| B. | Occurs in the resonator gap |
| C. | Occurs near the accelerating grid |
| D. | does not occur at all |
| Answer» D. does not occur at all | |
| 36. |
A large program is broken down into modules in which of the following phase? |
| A. | Requirement Analysis |
| B. | Design |
| C. | Development |
| D. | Deployment |
| Answer» C. Development | |
| 37. |
In the following lists, there are materials and their bandgap energies.Match the following Lists:List-I List-IIMaterial Bandgap Energies (eV)(a) GaAs(i) 0.73-1.35 eV(b) GaAlAs(ii) 0.96-1.24 eV(c) InGaAs(iii) 1.4-1.55 eV(d) InGaAsP(iv) 1.4 eV Correct codes are:Code: |
| A. | a-i, b-ii, c-iv, d-iii |
| B. | a-ii, b-i, c-iii, d-iv |
| C. | a-iv, b-iii, c-ii, d-i |
| D. | a-i, b-iii, c-iv, d-ii |
| Answer» D. a-i, b-iii, c-iv, d-ii | |
| 38. |
Intrinsic semiconductors at room temperature have: |
| A. | An equal number of holes and free electrons |
| B. | Number of holes does not depend upon the number of free electrons |
| C. | Number of holes < number of free electrons |
| D. | Number of holes > number of free electrons |
| Answer» B. Number of holes does not depend upon the number of free electrons | |
| 39. |
For material emitting 4 × 1014 Hz the band gap is ______ eV. |
| A. | 14.87 |
| B. | 1.33 |
| C. | 4.9 |
| D. | 1.653 |
| Answer» E. | |
| 40. |
For a given bipolar junction transistor the value of β is 99. What is the corresponding value of α? (symbols have their usual meanings) |
| A. | 0.01 |
| B. | 1.01 |
| C. | 1.99 |
| D. | 0.99 |
| Answer» E. | |
| 41. |
Pentavalent impurity atoms that are added to intrinsic semiconductor are called: |
| A. | Donor or N type impurities |
| B. | Acceptor |
| C. | Acceptor or P type impurities |
| D. | Donor or P type impurities |
| Answer» B. Acceptor | |
| 42. |
A circuit that operates in such a way that its output is high when all its inputs are high |
| A. | AND |
| B. | OR |
| C. | NOT |
| D. | NAND |
| Answer» B. OR | |
| 43. |
A p-type semiconductor is obtained if we dope ________. |
| A. | Silicon with a pentavalent element |
| B. | Silicon with a trivalent element |
| C. | a pentavalent element with Silicon |
| D. | a trivalent element with Silicon |
| Answer» C. a pentavalent element with Silicon | |
| 44. |
For a transistor in common emitter configuration ______________ is the ratio of change in base-emitter voltage (ΔVBE) to the resulting change in basecurrent (ΔIB) at constant collector-emitter voltage (VCE). |
| A. | Output resistance |
| B. | Current amplification factor |
| C. | Voltage gain |
| D. | Input resistance |
| Answer» E. | |
| 45. |
lf the wire which is vertical to this page has electron flow downwards the conductor will have |
| A. | no magnetic field |
| B. | a counter-clockwise field in the plane of the paper |
| C. | a clockwise field in the plane of the paper |
| D. | a counter-clockwise field in the plane perpendicular to the paper |
| Answer» C. a clockwise field in the plane of the paper | |
| 46. |
Pure semiconductors are poor conductor because |
| A. | They have no valence electrons |
| B. | All valence electrons are in electron - pairs |
| C. | They have a number of holes |
| D. | There are fewer electrons than protons |
| Answer» C. They have a number of holes | |
| 47. |
Generally, mobility of electrons in semiconductor is _________ times the mobility of holes: |
| A. | Two |
| B. | Three |
| C. | Four |
| D. | Five |
| Answer» C. Four | |
| 48. |
A semiconductor has ______ electrons in its valency ring. |
| A. | 3 |
| B. | 6 |
| C. | 0 |
| D. | 4 |
| Answer» E. | |
| 49. |
Atomic number of silicon is |
| A. | 12 |
| B. | 13 |
| C. | 14 |
| D. | 15 |
| Answer» D. 15 | |
| 50. |
In a transistor, the ______________ is moderately doped and largest in size. |
| A. | emitter |
| B. | base |
| C. | junction |
| D. | collector |
| Answer» E. | |