ESE-2018 Achiever Study Plan Electrical Material Quiz 1

Consider the following statements:
1) Nano means 10^–9 so that nano materials have an order of dimension higher than the size of atom and come in the form of rods, tubes, spheres or even thin sheets/films
2) Nano materials have enchanced of changed structural property
3) Nano elements lend themselves to mechanical processing like rolling, twisting, positioning
4) Nano elements show important electrical, magnetic and optical characteristics that are useful in electrical inductry
Which of the above statements are correct?

The dielectric strength of rubber is 40000 V/ mm at frequency of 50 Hz. What is the thickness of insulation required on an electrical conductor at 33 kV to sustain the breakdown?

The Hall voltage, V_H, for a thin copper plate of 0.1 mm carrying a current of 100 A with the flux density in the z-direction, B_z = 1 Wb/m² and the Hall coefficient, R_H = 7.4 × 10^-11 m³/ C, is

The following date are obtained by measurement on gold:
Density = 19.32 gm/cc
Resistivity = 2.42 -cm
Atomic weight = 197.2
The mobility of electrons in gold is

Consider the following statements:
1) Fermi level in a p-type semiconductor lies close to the top the valence bond.
2) The forbidden energy in Germanium at 0⁰K is exactly 0.75 eV.
3) When a p-n junction is reverse biased, then electrons and holes move away from the juction.
Which of these statements are correct?