Match List-I with List-II.
| List-I | List-II |
| (A) Metals | (I) Elements/compounds |
| (B) Pure semiconductors | (II) Extrinsic semiconductor |
| (C) Doped semiconductor | (III) Low resistivity |
| (D) Semiconductors | (IV) Intrinsic semiconductors |
Choose the correct answer from the options given below
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → (A)-(III), (B)-(IV), (C)-(II), (D)-(I)
Solids are grouped as metals, semiconductors and insulators by their resistivity, and semiconductors are further divided by whether impurities have been added.
(A) Metals — this matches (III) Low resistivity. Metals have a very large number of free electrons, so their resistivity is very low, about \( 10^{-2} \) to \( 10^{-8}\,\Omega\,\mathrm{m} \).
(B) Pure semiconductors — this matches (IV) Intrinsic semiconductors. In a pure semiconductor all the carriers come from the material itself, and the numbers of electrons and holes are equal (\( n_e = n_h = n_i \)).
(C) Doped semiconductor — this matches (II) Extrinsic semiconductor. Adding a small amount of a suitable impurity (doping) raises the conductivity many times; such a semiconductor is called extrinsic (n-type or p-type).
(D) Semiconductors — this matches (I) Elements/compounds. Semiconductors may be elements such as Si and Ge, or compounds such as GaAs and CdS.
NCERT (2026-27):
Summary – “… 3. Metals have low resistivity (10–2 to 10–8 Ω m), insulators have very high resistivity (>108 Ω m–1), while semiconductors have intermediate values of resistivity. 4. Semiconductors are elemental (Si, Ge) as well as compound (GaAs, CdS, etc.). 5. Pure semiconductors are called ‘intrinsic semiconductors’.”
Summary – “… 6. The number of charge carriers can be changed by ‘doping’ of a suitable impurity in pure semiconductors. Such semiconductors are known as extrinsic semiconductors.”