31. __________ is the main constituent of glass. A. Fe2O3 B. SiO2 C. AI2O3 D. B2O3 Answer & Solution Discuss in Board Save for Later Answer & Solution Answer: Option B No explanation is given for this question Let's Discuss on Board
32. In a superconductor the value of critical density depends upon A. Magnetic field strength B. Temperature C. Either A or B D. Both A and B Answer & Solution Discuss in Board Save for Later Answer & Solution Answer: Option D No explanation is given for this question Let's Discuss on Board
33. The co-ordination number of a simple cubic structure is B. 2 C. 4 D. 6 E. 8 Answer & Solution Discuss in Board Save for Later Answer & Solution Answer: Option C No explanation is given for this question Let's Discuss on Board
34. The conduction of electricity, in semiconductors, takes place due to movement of A. Positive ions only B. Negative ions only C. Positive and negative ions D. Electrons and holes Answer & Solution Discuss in Board Save for Later Answer & Solution Answer: Option D No explanation is given for this question Let's Discuss on Board
35. In conductors conduction of electricity takes place due to movement of A. Electrons only B. Positive ions only C. Negative ions only D. Positive and negative ions Answer & Solution Discuss in Board Save for Later Answer & Solution Answer: Option A No explanation is given for this question Let's Discuss on Board
36. A highly conductive material must have A. Highest conductivity B. Lowest temperature co-efficient C. Good mechanical strength D. Good corrosion resistance E. All of the above Answer & Solution Discuss in Board Save for Later Answer & Solution Answer: Option E No explanation is given for this question Let's Discuss on Board
37. Is an element used in semiconductors whose atoms have three valence electrons. A. An acceptor B. A donor C. Germanium D. Silicon Answer & Solution Discuss in Board Save for Later Answer & Solution Answer: Option A No explanation is given for this question Let's Discuss on Board
38. The coils of D.C. motor starter are wound with wire of A. Copper B. Kanthal C. Manganin D. Nichrome Answer & Solution Discuss in Board Save for Later Answer & Solution Answer: Option C No explanation is given for this question Let's Discuss on Board
39. Due to which of the following factors the brush wear rate is altered? A. Speed of the machine B. Contact pressure C. Surface conditions of brush and commutator D. All of the above Answer & Solution Discuss in Board Save for Later Answer & Solution Answer: Option D No explanation is given for this question Let's Discuss on Board
40. Which of the following affect greatly the resistivity of electrical conductors? A. Composition B. Pressure C. Size D. Temperature Answer & Solution Discuss in Board Save for Later Answer & Solution Answer: Option A No explanation is given for this question Let's Discuss on Board