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.
| 451. |
The resistivity of a semiconductor |
| A. | increases as the temperature increases |
| B. | decreases as the temperature increases |
| C. | remains constant even when temperature varies |
| D. | none of the above |
| Answer» C. remains constant even when temperature varies | |
| 452. |
The drain characteristics of JFET in operating region, are |
| A. | inclined upwards |
| B. | almost flat |
| C. | inclined downwards |
| D. | inclined upwards or downwards |
| Answer» C. inclined downwards | |
| 453. |
In a CE bipolar transistor operating in active region, collector current is independent of |
| A. | VCE |
| B. | IB |
| C. | both VCE and IB |
| D. | none of the above |
| Answer» B. IB | |
| 454. |
As temperature increases the forbidden gap in silicon increases. |
| A. | True |
| B. | False |
| C. | May be True or False |
| D. | Can't say |
| Answer» C. May be True or False | |
| 455. |
If a sample of Ge and a sample of Si have the same impurity density are kept at room temperature |
| A. | both will have equal value of resistivity |
| B. | both will have equal - ve of resistivity |
| C. | resistivity of germanium will be higher than that of silicon |
| D. | resistivity of silicon will be higher than of Ge |
| Answer» E. | |
| 456. |
The saturation current in a semi-conductor diode |
| A. | depends on forward voltage |
| B. | depends on reverse voltage |
| C. | is due to thermally generated minority carriers |
| D. | none of the above |
| Answer» D. none of the above | |
| 457. |
If too large current passes through the diode |
| A. | all electrons will leave |
| B. | all holes will freeze |
| C. | excessive heat may damage the diode |
| D. | diode will emit light |
| Answer» D. diode will emit light | |
| 458. |
In the saturation region of CE output characteristics of n-p-n transistor, VCE is about |
| A. | 0.5 V |
| B. | 15 V |
| C. | - 0.5 V |
| D. | - 15 V |
| Answer» B. 15 V | |
| 459. |
An enhancement mode MOSFET is off when the gate voltage is |
| A. | zero |
| B. | negative |
| C. | less than threshold value |
| D. | none of the above |
| Answer» D. none of the above | |
| 460. |
Junction temperature is always the same as room temperature. |
| A. | True |
| B. | False |
| C. | May be True or False |
| D. | Can't say |
| Answer» C. May be True or False | |
| 461. |
The depletion layer across a P⁺ n junction lies |
| A. | mostly in the P⁺ region |
| B. | mostly in n region |
| C. | equally in both the P⁺ and n-region |
| D. | entirely in the P⁺ region |
| Answer» B. mostly in n region | |
| 462. |
When the i-v curve of a photodiode passes through origin the illumination is |
| A. | maximum |
| B. | minimum |
| C. | zero |
| D. | equal to rated value |
| Answer» D. equal to rated value | |
| 463. |
When a semiconductor bar is heated at one end, a voltage across the bar is developed. If the heated is positive the semiconductor is |
| A. | P-type |
| B. | n-type |
| C. | intrinsic |
| D. | highly degenerate |
| Answer» E. | |
| 464. |
The main purpose of using transformer coupling in a class A amplifier is to make it more |
| A. | efficient |
| B. | less costly |
| C. | less bulky |
| D. | distortion free |
| Answer» E. | |
| 465. |
When an electron breaks a covalent bond and moves away, |
| A. | a hole is created |
| B. | a proton is also lost |
| C. | atom becomes an ion |
| D. | rest of the electron move at a faster rate |
| Answer» B. a proton is also lost | |
| 466. |
The dc output voltage from a power supply |
| A. | increases with higher values of filter capacitance and decreases with more load current |
| B. | decreases with higher values of filter capacitance and increases with more load current |
| C. | decreases with higher values of filter capacitance as well as with more load current |
| D. | increases with higher values of filter capacitance as well as with more load current |
| Answer» B. decreases with higher values of filter capacitance and increases with more load current | |
| 467. |
Assertion (A): Intrinsic semiconductor is an insulator at 0 K.Reason (R): Fermi level in intrinsic semiconductor is in the centre of forbidden energy band. |
| 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 | |
| 468. |
For radiating ultraviolet rays, LEDs use |
| A. | zinc sulphide |
| B. | gallium arsenide |
| C. | gallium phosphide |
| D. | none of the above |
| Answer» B. gallium arsenide | |
| 469. |
A Varactor diode has |
| A. | a fixed capacitance |
| B. | a fixed inductance |
| C. | a voltage variable capacitance |
| D. | a current variable inductance |
| Answer» D. a current variable inductance | |
| 470. |
The carriers of n channel JFET are |
| A. | free electrons and holes |
| B. | holes |
| C. | free electrons or holes |
| D. | free electrons |
| Answer» E. | |
| 471. |
Assertion (A): The reverse saturation current in a semiconductor diode is 4nA at 20°C and 32 nA at 50°C.Reason (R): The reverse saturation current in a semiconductor diode doubles for every 10°C rise in temperature. |
| 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 | |
| 472. |
The drift velocity of electrons and holes is proportional to electric field strength. |
| A. | True |
| B. | False |
| C. | May be True or False |
| D. | Can't say |
| Answer» B. False | |
| 473. |
As temperature increases |
| A. | the forbidden energy gap in silicon and germanium increase |
| B. | the forbidden energy gap in silicon and germanium decrease |
| C. | the forbidden energy gap in silicon decreases while that in germanium decreases |
| D. | the forbidden energy gap in silicon increases while that in germanium decreases |
| Answer» C. the forbidden energy gap in silicon decreases while that in germanium decreases | |
| 474. |
The turn off time of a bipolar transistor is about |
| A. | 0.5 ns |
| B. | 10 ns |
| C. | 70 ns |
| D. | 150 ns |
| Answer» D. 150 ns | |
| 475. |
Which of the following is the ferric electric material? |
| A. | Rochelle salt |
| B. | Barium titanate |
| C. | Potassium dihydrogen phosphate |
| D. | All of the above |
| Answer» E. | |
| 476. |
Assertion (A): Alkali metals are used as emitters in phototubes.Reason (R): Alkali metals have low work functions. |
| 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 | |
| 477. |
A full wave bridge rectifier is supplied voltage at 50 Hz. The lowest ripple frequency will be |
| A. | 400 Hz |
| B. | 200 Hz |
| C. | 100 Hz |
| D. | 50 Hz |
| Answer» D. 50 Hz | |
| 478. |
Assertion (A): When p-n junction is forward biased, steady current flows.Reason (R): When a p-n junction is forward biased, free electrons cross the junction from n to p and holes from p to n. |
| 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 | |
| 479. |
The static characteristic of an adequately forward biased P-n junction is a straight line, if the plot is of __________ Vs → versus |
| A. | log I Vs log V |
| B. | log I Vs V |
| C. | I Vs log V |
| D. | I Vs V |
| Answer» C. I Vs log V | |
| 480. |
If 10 V is the peak voltage across the secondary of the transformer in a half wave rectifier (without any filter circuit), then the maximum voltage on the reverse biased diode will be |
| A. | 20 V |
| B. | 14.14 V |
| C. | 10 V |
| D. | 7.8 V |
| Answer» D. 7.8 V | |
| 481. |
The diffusion current is proportional to |
| A. | applied electric field |
| B. | concentration gradient of charge carrier |
| C. | square of the electric field |
| D. | cube of the applied electric field |
| Answer» C. square of the electric field | |
| 482. |
In which region of a CE bipolar transistor is collector current almost constant? |
| A. | Saturation region |
| B. | Active region |
| C. | Breakdown region |
| D. | Both saturation and active region |
| Answer» C. Breakdown region | |
| 483. |
If ib is plate current, eb is plate voltage and ec is grid voltage the v-i curve of a vacuum triode is ib = 0.003 (eb + kec)ⁿ. Typical values of k and n are |
| A. | 0.5 and 1 |
| B. | - 2 and 1 |
| C. | 30 and 1 |
| D. | 30 and 1.5 |
| Answer» E. | |
| 484. |
The conductivity of an intrinsic semiconductor is |
| A. | generally less than that of a doped semiconductor |
| B. | given by σ1 = eni (μn - μp) |
| C. | given by σ1 = eni (μp + μn) |
| D. | given by σ1 = ni (μn + μp) |
| Answer» D. given by σ1 = ni (μn + μp) | |
| 485. |
Assertion (A): In reverse biased p-n junction, the reverse saturation current is nearly constant if the reverse voltage is less than critical value.Reason (R): The total reverse current is sum of reverse saturation current and surface leakage current. |
| 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 | |
| 486. |
Lowest noise can be expected in case of |
| A. | carbon composition resistors |
| B. | carbon film resistors |
| C. | tin oxide resistors |
| D. | metal film resistors |
| Answer» E. | |
| 487. |
Which of the following constitutes an active component? |
| A. | Semiconductor device |
| B. | Resistors |
| C. | Capacitors |
| D. | Inductors |
| Answer» B. Resistors | |
| 488. |
Assertion (A): Germanium is more commonly used than silicon.Reason (R): Forbidden gap in germanium is less than that in silicon. |
| 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. | |
| 489. |
The most important set of specifications of transformer oil includes |
| A. | dielectric strength and viscosity |
| B. | dielectric strength and flash point |
| C. | flash point and viscosity |
| D. | dielectric strength, flash point and viscosity |
| Answer» E. | |
| 490. |
At absolute temperature |
| A. | the forbidden energy gap in germanium is higher than that in silicon |
| B. | the forbidden energy gap in germanium and silicon are equal |
| C. | the forbidden energy gap in silicon is higher than that in germanium |
| D. | none of the above |
| Answer» D. none of the above | |
| 491. |
A good ohmic contact on a P-type semiconductor chip is formed by introducing |
| A. | gold as an impurity below the contact |
| B. | high concentration of donors below the contact |
| C. | high concentration of acceptors below the contact |
| D. | thin insulator layer between the metal and semiconductor |
| Answer» C. high concentration of acceptors below the contact | |
| 492. |
The conductivity of materials found in nature ranges from 10⁹ ohm¯¹m¯¹ to nearly 10¹⁸ ohm¯¹ m¯¹ from this it can be concluded that the conductivity of silicon in ohm¯¹ cm¯¹ will be nearly |
| A. | 0.5 x 10¯¹⁵ |
| B. | 0.5 x 10¯²¹ |
| C. | 0.5 x 10¯¹² |
| D. | 0.5 x 10¯³ |
| Answer» E. | |
| 493. |
In what condition does BJT act like an open switch |
| A. | cut off |
| B. | saturation |
| C. | active |
| D. | both (b) and (c) |
| Answer» B. saturation | |
| 494. |
Which of these has degenerate p and n materials? |
| A. | Zener diode |
| B. | PIN diode |
| C. | Tunnel diode |
| D. | Photo diode |
| Answer» D. Photo diode | |
| 495. |
In forward active region, the operation of a BJT |
| A. | both junctions are forward biased |
| B. | both junctions are reverse biased |
| C. | emitter base junction is forward biased and base collector junction is reverse biased |
| D. | emitter base junction is reverse biased and base collector junction is reverse biased |
| Answer» D. emitter base junction is reverse biased and base collector junction is reverse biased | |
| 496. |
The relation between plate current and plate voltage of a vacuum diode is called |
| A. | Richardson Dushman equation |
| B. | Langmuir Child law |
| C. | Ohm's law |
| D. | Boltzmann's law |
| Answer» C. Ohm's law | |
| 497. |
Piezoelectric materials serves as a source of |
| A. | microwaves |
| B. | ultrasonic waves |
| C. | musical waves |
| D. | resonant waves |
| Answer» C. musical waves | |
| 498. |
The equivalent circuit of an ideal diode is |
| A. | a charging condenser |
| B. | a discharging condenser |
| C. | a switch |
| D. | a resistor |
| Answer» D. a resistor | |
| 499. |
EG for silicon is 1.12 eV and that for germanium is 0.72 eV. Therefore, it can be concluded that |
| A. | the conductivity of silicon will be less than that of germanium at room temperature |
| B. | the conductivity of silicon will be more than that of germanium at room temperature |
| C. | the conductivity of two will be same at 60°C |
| D. | the conductivity of two will be same at 100°C |
| Answer» B. the conductivity of silicon will be more than that of germanium at room temperature | |
| 500. |
The breakdown voltage in a zener diode |
| A. | is almost constant |
| B. | is very small |
| C. | may destroy the diode |
| D. | decreases with increase in current |
| Answer» B. is very small | |