Materials And Components MCQ Questions & Answers | ECE

Which of the following is not a permanent magnetic material?

A rolled-paper capacitor of value 0.02 µF is to be constructed using two strips of aluminium of width 6 cm, and, wax impregnated paper of thickness 0.06 mm whose relative permittivity is 3. The length of foil strips should be:

A small amount of phosphorus is added to silicon so that there are 2.5 × 10¹⁷ conduction electrons per cubic meter and 9.0 × 10¹⁴ holes per cubic meter. Let µ_e = 0.13 m²/V.s and µ_h = 0.05 m²/V.s. The resistivity in Ω - m will be

Consider the following statements regarding corrosion of ceramic material:
1. Ceramic materials are much better suited to withstand most of these environments for reasonable time periods than are metals.
2. Corrosion of ceramic materials generally involves simple chemical dissolution, in contrast to the electrochemical processes found in metals.
3. Ceramic materials are not frequently used because of their non-resistance to corrosion.
Which of the above statements is/are correct?

Silicon is not suitable for fabrication of light emitting diodes because it is

The capacitance per unit volume is maximum for

Which one of the following statement is correct forbidden gap for four-point probe method of determining resistivity?

The dc resistivity and permeability exhibited by a type 1 superconductor are respectively:

Consider the following
1. Cheaper method
2. Low residual oxygen content in the grown crystal is possible
3. Uniform doping is possible
4. Larger diameter crystals can be grown
Which of the above are the advantages of the float zone (FZ) method over the Czochralski (CZ) method in single crystal growth of silicon?

The atomic packing factor (APF) is equal to