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.
| 151. |
The electron and hole concentration in a intrinsic semiconductor are ni and Pi respectively when doped with a P type material, these change to n and P, respectively. Then |
| A. | n + P = ni + Pi |
| B. | n + ni = P + Pi |
| C. | nPi = niP |
| D. | nP = ni Pi |
| Answer» E. | |
| 152. |
When a p-n junction is forward biased, the current remains zero till the applied voltage overcomes the barrier potential. |
| A. | True |
| B. | False |
| C. | May be True or False |
| D. | Can't say |
| Answer» B. False | |
| 153. |
In order to achieve good stabilization in potential divider method current I1 through R1 and R2 should be |
| A. | I1 > 20 IB |
| B. | I1 > 15 IB |
| C. | I1 < 5 IB |
| D. | I1 > 10 IB |
| Answer» E. | |
| 154. |
In an ideal junction transistor the impurity concentration in emitter (E ), base (B) and collector (C) is such that |
| A. | E > B > C |
| B. | B > C > E |
| C. | C > E > B |
| D. | C = E = B |
| Answer» B. B > C > E | |
| 155. |
Which of the following are voltage controlled devices? |
| A. | Vacum triode |
| B. | FET |
| C. | SCR |
| D. | Both (a) and (b) |
| Answer» E. | |
| 156. |
Secondary emission results |
| A. | when temperature of metals is raised to a level above the crystallization temperature |
| B. | when metals are subjected to strong magnetic fields |
| C. | when light rays fall on the metal surface |
| D. | when a high velocity beam of electrons strikes as metal surface |
| Answer» C. when light rays fall on the metal surface | |
| 157. |
A sample of N type semiconductor has electron density of 6.25 x 10⁸/cm² at 300 K. If the intrinsic concentration of carriers in this sample is 2.5 x 10¹³/cm³ at this temperature, the hole density works out to be |
| A. | 10⁶/cm³ |
| B. | 10⁸/cm³ |
| C. | 10¹ᴼ/cm³ |
| D. | 10¹²/cm³ |
| Answer» C. 10¹ᴼ/cm³ | |
| 158. |
Which of the following exhibits negative resistance in a portion of its characteristics? |
| A. | Tunnel diode |
| B. | Zener diode |
| C. | JFET |
| D. | MOSFET and tunnel diode |
| Answer» B. Zener diode | |
| 159. |
Hystresis loss least depends on |
| A. | frequency |
| B. | magnetic field intensity |
| C. | volume of the material |
| D. | grain orientation of material |
| Answer» E. | |
| 160. |
In a 741 OP-amp, there is 20 dB/decade fall-off starting at a relatively low frequency. This is due to |
| A. | applied load |
| B. | internal compensation |
| C. | impedance of the source |
| D. | power dissipation in the chip |
| Answer» E. | |
| 161. |
In p type semiconductor holes are majority carriers. |
| A. | True |
| B. | False |
| C. | May be True or False |
| D. | Can't say |
| Answer» B. False | |
| 162. |
A Schottky diode clamp is used along with switching BJT for |
| A. | reducing the power dissipation |
| B. | reducing the switching time |
| C. | increasing the value of β |
| D. | reducing the base current |
| Answer» C. increasing the value of β | |
| 163. |
The amount of photoelectric emission current depends on |
| A. | frequency of incident radiation |
| B. | intensity of incident radiation |
| C. | both frequency and intensity of incident radiation |
| D. | none of the above |
| Answer» C. both frequency and intensity of incident radiation | |
| 164. |
Which of the following is used in the sterilization of water? |
| A. | Hydrogen bromide |
| B. | Oxygen |
| C. | Ozone |
| D. | Caustic potash |
| Answer» D. Caustic potash | |
| 165. |
In a bipolar transistor the barrier potential |
| A. | 0 |
| B. | a total of 0.7 V |
| C. | 0.7 V across each depletion layer |
| D. | 0.35 V |
| Answer» D. 0.35 V | |
| 166. |
In the fabrication of n-p-n transistor in an IC, the buried layer on the P-type substrate is |
| A. | P⁺ -doped |
| B. | n⁺ -doped |
| C. | used to reduce the parasitic capacitance |
| D. | located in the emitter region |
| Answer» D. located in the emitter region | |
| 167. |
Calculate the resistivity of n-type semiconductor from the following data, Density of holes = 5 x 10¹² cm¯³. Density of electrons = 8 x 10¹³ cm¯³, mobility of conduction electron = 2.3 x 10⁴ cm²/ V-sec and mobility of holes = 100 cm²/V-sec. |
| A. | 0.43 Ω-m |
| B. | 0.34 Ω-m |
| C. | 0.42 Ω-m |
| D. | 0.24 Ω-m |
| Answer» C. 0.42 Ω-m | |
| 168. |
An intrinsic silicon sample has 2 million free electrons. The number of holes in the sample is |
| A. | 2 million |
| B. | almost zero |
| C. | more than 2 million |
| D. | less than 2 million |
| Answer» B. almost zero | |
| 169. |
The mean life time of the minority carriers is in the range of a few |
| A. | seconds |
| B. | milli seconds |
| C. | micro seconds |
| D. | nano seconds |
| Answer» E. | |
| 170. |
Which of the following characteristics of a silicon p-n junction diode make it suitable for use as ideal diode? 1. It has low saturation current.2. It has high value of cut in voltage.3. It can withstand large reverse voltage.4. When compared with germanium diode, silicon diode shows a lower degree of temperature dependence under reverse conditions. Select the answer using the given below |
| A. | 1 and 2 |
| B. | 1, 2, 3, 4 |
| C. | 2, 3, 4 |
| D. | 1, 3 |
| Answer» C. 2, 3, 4 | |
| 171. |
The number of valence electrons in a donor atom is |
| A. | 2 |
| B. | 3 |
| C. | 4 |
| D. | 5 |
| Answer» E. | |
| 172. |
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 | |
| 173. |
Eg is the band gap, A is pre-factor, k is Boltzmann constant? Which one of the following is the remaining grade of paper used in paper capacitor, besides the other two grade of paper-low and extra low loss? |
| A. | Strong dielectric |
| B. | Regular |
| C. | Rough |
| D. | High loss |
| Answer» C. Rough | |
| 174. |
Electrons within a metal have energy levels from zero to Fermi level EF. |
| A. | True |
| B. | False |
| C. | May be True or False |
| D. | Can't say |
| Answer» B. False | |
| 175. |
At room temperature kT = 0.03 eV. |
| A. | True |
| B. | False |
| C. | May be True or False |
| D. | Can't say |
| Answer» B. False | |
| 176. |
Introducing a resistor in the emitter of a common amplifier stabilizes the d.c. operating point against variations in |
| A. | only the temperature |
| B. | only β of the transistor |
| C. | both temperature and β |
| D. | none of these |
| Answer» D. none of these | |
| 177. |
From an n channel JFET for VDS constant and if VGS is made more negative, pinch off would occur at |
| A. | higher value of drain current |
| B. | saturation value of drain current |
| C. | zero drain current |
| D. | gate current equal to drain current |
| Answer» D. gate current equal to drain current | |
| 178. |
When a p-n-p transistor is operating in active region, the current in the n region is due to |
| A. | only holes |
| B. | only electrons |
| C. | mainly holes |
| D. | mainly electrons |
| Answer» D. mainly electrons | |
| 179. |
When a p-n junction is reverse biased |
| A. | holes and electrons move away from the junction |
| B. | holes and electrons move towards the junction |
| C. | holes move towards junction and electrons move away from junction |
| D. | holes move away from junction and electrons move towards junction |
| Answer» B. holes and electrons move towards the junction | |
| 180. |
Assertion (A): In p type semiconductor conduction is mainly due to holes.Reason (R): In p type material the 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» B. Both A and R are true but R is not a correct explanation of A | |
| 181. |
Ohmic range of metal film resistors is |
| A. | 1 to 100 ohms |
| B. | 10 to 1 K ohms |
| C. | 100 to 1 M ohms |
| D. | 100 to 100 M ohms |
| Answer» D. 100 to 100 M ohms | |
| 182. |
The depletion layer around p-n junction in JFET consists of |
| A. | hole |
| B. | electron |
| C. | immobile charges |
| D. | none of the above |
| Answer» D. none of the above | |
| 183. |
The kinetic energy of free electrons in a metal is (where k is the de-Broglie wave number of the electron) |
| A. | inversely proportional to k |
| B. | inversely proportional to square of k |
| C. | proportional to k |
| D. | proportional to the square of k |
| Answer» C. proportional to k | |
| 184. |
In a bipolar transistor which current is smallest |
| A. | collector current |
| B. | base current |
| C. | emitter current |
| D. | any of the three currents |
| Answer» C. emitter current | |
| 185. |
Assertion (A): When forward biased a p-n junction has low resistance.Reason (R): The ratio dv/di is called dynamic resistance. |
| 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 | |
| 186. |
Greatest mobility can be expected in case of |
| A. | holes |
| B. | protons |
| C. | electrons |
| D. | negative ions |
| Answer» D. negative ions | |
| 187. |
If E is electric field intensity, the current density due to field emission is proportional to |
| A. | E |
| B. | E^2 |
| C. | E^2.5 |
| D. | E^3/2 |
| Answer» C. E^2.5 | |
| 188. |
When a large number of atoms are brought together to form a crystal |
| A. | the energy levels of inner shell electrons are affected appreciably by the presence of other neighbouring atoms. |
| B. | The energy levels of outer shell electrons are affected appreciably by the presence of other neighbouring atoms. |
| C. | the energy levels of both inner and outer shell electrons are affected appreciably by the presence of other neighbouring atoms. |
| D. | none of the above. |
| Answer» C. the energy levels of both inner and outer shell electrons are affected appreciably by the presence of other neighbouring atoms. | |
| 189. |
The ratio of diffusion constant for hole DP to the mobility for holes is proportional to |
| A. | T² |
| B. | T |
| C. | 1/T |
| D. | T³ |
| Answer» C. 1/T | |
| 190. |
Varactor diode is forward biased when it is used. |
| A. | True |
| B. | False |
| C. | May be True or False |
| D. | Can't say |
| Answer» C. May be True or False | |
| 191. |
The capacitor filter provides poor voltage regulation because |
| A. | the increase in ripple with load current causes a decrease in average voltage |
| B. | the increase in ripple with load current causes a increase in average voltage |
| C. | filter promotes ripple at peak voltage |
| D. | none of the above |
| Answer» B. the increase in ripple with load current causes a increase in average voltage | |
| 192. |
When the gate terminal of MOSFET is positive, it is said to operate in |
| A. | depletion mode |
| B. | conduction mode |
| C. | enhancement mode |
| D. | none of the above |
| Answer» D. none of the above | |
| 193. |
A doped semi-conductor is called |
| A. | impure semi-conductor |
| B. | dipole semi-conductor |
| C. | bipolar semi-conductor |
| D. | extrinsic semi-conductor |
| Answer» E. | |
| 194. |
Assertion (A): Tunnel diode is used in many pulse and digital circuits. Reason (R): The v-i curve of a tunnel diode resembles letter '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 | |
| 195. |
In a transistor operating in forward active mode |
| A. | depletion layer between emitter and base is thin and that between base and collector is also thin |
| B. | both depletion regions are thick |
| C. | depletion layer between emitter and base is thin and that between base and collector is thick |
| D. | depletion layer between emitter and base is thick and that between base and collector is thin |
| Answer» D. depletion layer between emitter and base is thick and that between base and collector is thin | |
| 196. |
A periodic voltage has following value for equal time intervals changing suddenly from one value to next... 0, 5, 10, 20, 50, 60, 50, 20, 10, 5, 0, -5, -10 etc. Then rms value of the waveform is |
| A. | 31 V |
| B. | 32 V |
| C. | insufficient data |
| D. | none of these |
| Answer» B. 32 V | |
| 197. |
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 | |
| 198. |
What is the correct sequence of the following step in the fabrication of a monolithic, Bipolar junction transistor? Emitter diffusionBase diffusionBuried layer formationE pi-layer formation Select the correct answer using the codes given below: |
| A. | 3, 4, 1, 2 |
| B. | 4, 3, 1, 2 |
| C. | 3, 4, 2, 1 |
| D. | 4, 3, 2, 1 |
| Answer» E. | |
| 199. |
Secondary emission is always decremental. |
| A. | True |
| B. | False |
| C. | May be True or False |
| D. | Can't say |
| Answer» C. May be True or False | |
| 200. |
An increase of reverse voltage decreases the junction capacitance. |
| A. | True |
| B. | False |
| C. | May be True or False |
| D. | Can't say |
| Answer» B. False | |