ELECTRONICS-QUIZ 19

ELECTRONICS-QUIZ 19

Dear Readers,

As per analysis for previous years, it has been observed that students preparing for NEET find Physics out of all the sections to be complex to handle and the majority of them are not able to comprehend the reason behind it. This problem arises especially because these aspirants appearing for the examination are more inclined to have a keen interest in Biology due to their medical background. Furthermore, sections such as Physics are dominantly based on theories, laws, numerical in comparison to a section of Biology which is more of fact-based, life sciences, and includes substantial explanations. By using the table given below, you easily and directly access to the topics and respective links of MCQs. Moreover, to make learning smooth and efficient, all the questions come with their supportive solutions to make utilization of time even more productive. Students will be covered for all their studies as the topics are available from basics to even the most advanced. .

Q1. Identify the system of crystal structure, if a=b≠c α=β=90° and γ=120°.

•  Monoclinic
•  Triclinic
•  Hexagonal
•  Rhombohedral

Solution
(c) For hexagonal crystal structure, a=b≠c and α=β=90° but γ=120°.

Q2.If the lattice constant of this semiconductor is decreased, then which of the following is correct?

•  All E_c,E_g,E,_v increase
•  E_c and E_v increase, but E_g decreases
•  E_c and E_v decrease, but E_g increases
•  All E_c,E_g,E_v decreases

Solution
(c) If lattice constant of semiconductor is decreased, then E_c and E_v decrease, but E_g increases.

Q3. Energy gap between valence band and conduction band of a semiconductor is

•  Zero
•  Infinite
•  1 eV
•  10 eV

Solution
(c)1 eV

Q4. In a P-type semiconductor, the acceptor impurity produces an energy level

•  Just below the valence band
•  Just above the conduction band
•  Just below the conduction band
•  Just above the valence band

Solution
(d) Also know that in an N-type semiconductor the donor energy level lies just below the conduction band

Q5.The combination of the following gates produces

•  AND gate
•  NAND gate
•  NOR gate
•  OR gate

Solution
(a) AND gate  

Q6. The current through an ideal PN-junction shown in the following circuit diagram will

•  Zero
•  1 mA
• 10 mA
•  30 mA

Solution
(a) The diode is in reverse biasing so current through it is zero

Q7.In the forward bias arrangement of a PN-junction diode

•  The N-end is connected to the positive terminal of the battery
•  The P-end is connected to the positive terminal of the battery
•  The direction of current is from N-end to P-end in the diode
•  The P-end is connected to the negative terminal of battery

Solution
(b)The P-end is connected to the positive terminal of the battery

Q8.If the output of a logic gate is 0 when all its inputs are at logic 1, then the gate is either

•  NAND or Ex-NOR
•  NOR or OR
•  Ex-OR or NOR
•  AND or NOR

Solution
(a) If A=1,B=1 and Y=0, the gate can be NOR gate, NAND gate or exclusive NOR gate (ie, XOR gate).

Q9.The density for simple cubic lattice is (where A is atomic weight, N is Avogadro’s number and a is a lattice parameter)

•  4A/(Na³ )
•  2A/(Na³ )
•  A/(Na³ )
•  A/(Na²)

Solution
(c) In simple cubic lattice, volume, V=a³ density=(mass of unit cell)/(volume of unit cell)=(A/N)/V=A/(Na³ )

Q10. In LED visible light is produced by

•  Gallium phosphide
•  Gallium arsenide
•  Germanium phosphide
•  Silicon phosphide

Solution
(b) In materials like gallium arsenide the number of photons of light energy is sufficient to produce quite intense visible light.