MCQ
C and Si both have the same lattice structure, having 4 bonding electrons in each. However, C is an insulator whereas Si is an intrinsic semiconductor. This is because
A. In case of C the valence band is not completely filled at absolute zero temperature.
B. In case of C the conduction band is partly filled even at absolute zero temperature.
C. The four bonding electrons in the case of C lie in the second orbit, whereas in the case of Si they lie in the third.
D. The four bonding electrons in the case of C lie in the third orbit, whereas for Si they lie in the fourth orbit.
  • A
    Option B
  • B
    Option A
  • C
    Option D
  • D
    Option C

Answer

(d) Option C
Explanation: ${ }^6 C : 1 s^2 2 s^2 2 p^2$
${ }^{14} Si : 1 s^2 2 s^2 2 p^6 3 s^2 3 p^2$
The energy required to take out an electron from the 3rd orbit of Si is much smaller than to take out an electron from the 2nd orbit of C. So, Si has a significant number of free electrons while C has a negligibly small number of free electrons.

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Similar questions

A point charge q is rotated along a circle in the electric field generated by another point charge $Q$. The work done by the electric field on the roatating charge in one complete revolution is:
During a nuclear fission reaction:
Seven resistances are connected as shown in the figure. The equivalent resistance between A and B is
For moving ball of cricket, the correct statement about de-Broglie wavelength is
A $100\, ohm$ galvanometer gives full scale deflection at $10\, mA$. How much shunt is required to read $100\, mA$ .............. $ohm$
Two uniformly charged spherical conductors $A$ and $B$ of radii $5 mm$ and $10 mm$ are separated by a distance of $2 cm$. If the spheres are connected by a conducting wire, then in equilibrium condition, the ratio of the magnitudes of the electric fields at the surface of the sphere $A$ and $B$ will be .
The energy density in the electric field created by a point charge falls off with the distance from the point charge as:
Electric field at a point varies as $r^0$ for
In an astronomical telescope, the focal length of the objective lens is $100 \,cm$ and of eye-piece is $2 \,cm.$ The magnifying power of the telescope for the normal eye is
Given below are two statements :

Statement $I :$ Stopping potential in photoelectric effect does not depend on the power of the light source.

Statement $II :$ For a given metal, the maximum kinetic energy of the photoelectron depends on the wavelength of the incident light.

In the light of above statements, choose the most appropriate answer from the options given below.

Options :