So, since we do not know A we need to find that first. Given that the density of copper = 8.92 × 103 kg/m3, Resistivity of copper = 1.73 × 10 –8 ohm-m, atomic weight of copper = 63.5 and Avogadro’s number = 6.02 × 10 26 per k-mol. It is the most commonly used material after silicon; however, it is more expensive and more difficult to manufacture. m. First we find the resistance of the silicone rod, and we do this using the equation R = ρL/A, where R is resistance, ρ is resistivity, L is length of the conductor and A is the cross sectional area. It can be seen that the resistivity of copper and the resistivity of brass both low and in view of their cost, relative to silver and gold, they become cost effective materials to use for many wires. Mobility of conduction electrons of copper, μ = ? Arsenic and Phosphorus provide electron mobilities, Boron provides hole mobility. In terms of energy bands, semiconductors can be defined as those materials which have almost an empty conduction band and almost filled valence band with a very narrow energy gap separating the two bands  R = ((2.30x10^3)(24.5e-2))/(4.6e-4). Explanation:- Intrinsic Silicon Properties • Read textbook, section 3.2.1, 3.2.2, 3.2.3 • Intrinsic Semiconductors – undoped (i.e., not n+ or p+) silicon has intrinsiccharge carriers – electron-hole pairs are created by thermal energy – intrinsic carrier concentration≡n i = 1.45x1010 cm-3, at room temp. Show Explanation The important property of electrons is determined by the rule that is called the Pauli exclusion principle. Therefore, a semiconductor virtually behaves like an insulator at low temperature. 2003), (Set-4–Nov. A semiconductor has ____________ temperature coefficient of resistance. The RH of a specimen is 3.66 × 10-4 m3/c. 2. In a pure semiconductor the four valence electrons of the crystal atom form covalent bonding and at low temperatures, free electrons are not available for conduction of electricity. Given that the atomic weight of silicon is 28.09, density = 2.33 × 103 kg/m3 electron and hole mobilities are 0.14 m2/V-s and 0.05 m2/V-s, respectively. Calculate the mobility of the electrons in copper obeying classical laws. The energy gap of the conductor is 0 eV. When a pure semiconductor is heated, it’s resistance_______. Einsteins equivalence principle and radiation from accelerating electric charges. Pure germanium at 300 K has a density of charge carries 2.5 × 1019/m3. 7. 7 em and for silicon 1.1 em The band structure of a semiconductor is shown in Figure. Thus, the valence band has holes while the conduction band has electrons. For ease of understanding, only the outermost orbits of atoms have been shown. Explanation: The Conductors with a uniform cross-section and uniform flow of electric current is called as resistivity. The valence band may be partially or completely filled up depending upon the nature of the crystal.