Question

need help with number 4 and 5 please!

Two, cm diameter circular metal plates have 0.10 mm thick mica disk (dielectric constant 54) between them. What oss the capacitance of the structure. Also, how many a 10 a resistor for 1.5 min. How many electrons enter the resistor electrons leave the resistor? Copper has mass density of 86 glam a copper wire, is one electron available per n there Q) copper atom to carry electrical current. What is the concentration of electrons in copper wire? Q) A 1.6 mm diameter aluminum aument of 2.9 A. What is the speed with which conducting electrons travel through the wire? The consternation of conducting is 1.81x102 cm 3 Q) concentration of electrons in Aluminum wire is 1.8ux102 Assuming that there is 1 conducting electran per aluminum determine the mass density of alumini Q How much work is required to bring 2 charges, q iuc and Q -1 from being 2 m apart 1uc to being 1 cm apart? Q) How much energy is required to move the 2.5 no from a location in space where electrostatic potential is 10 V to a place in space where the potential is -90 V? Q) A pure gold wire with circular profile of 2 mm in diameter carries a flow of electrons having current density of 1.0 long does take for 1Avogadron number warth of electrons to cruss what is the equivalent capacitance of taree capacitors, 2 nF 3 nF and 4 BF respectively, connected what is the equivalent resistance of three resistors, 20 30 and 40 respectively. onnected in parallel?

Answer 1

Diameter d = 2r = 1.6mm I = 2.9A $ n = 1.81 times 10^22/cm^3 drift speed v_d = ? by relation I = n e A v_d we get v_d = i/n e A = 2.9/1.81 times 10^22 times 10^6 times pi(d/2)^2 times 1.6 times 10^-19 therefore v_d = 49.8 times 10^-5 m/s n = 1.81 times 10^22 cm^-3 = 1.81 times 10^28 m^3 therefore no of atoms in 1m^3 = 1.81 times 10^28 mass of 1m^3 aluminium = 1 81 times 10^28 times 27/6 times 10^23 g therefore Density p = 814.5 kg/m^3