- ASilver, copper, gold
- BPaper, glass, cotton
- CThe human body, wood, iron
- DGlass, copper, paper
Explanation:
Glass, paper, and cotton are good quality insulators. The rest options contain one or more conducting materials. Silver is the best conductor material available in nature. But it is costly, so it can’t be used in the electricity distribution system.
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A straight wire carrying current i is turned into a circular loop. If the magnitude of magnetic moment associated with it in M.K.S. unit is M, the length of wire will be
|
(a) 4πiM |
(b) |
(c) |
(d) |
The wavelength of X-rays decreases, when
|
(a) Temperature of target is increased |
|
(b) Intensity of electron beam is increased |
|
(c) K.E. of electrons striking the target is increased |
|
(d) K.E. of electrons striking the target is decreased |
In an insulator, the forbidden energy gap between the valence band and conduction band is of the order of
| (a) 1 MeV | (b) 0.1 MeV |
(c) 1eV |
(d) 5 eV |
The impurity atom added to germanium to make it N-type semiconductor is
|
(a) Arsenic |
(b) Iridium |
(c) Aluminium |
(d) Iodine |
The output of OR gate is 1
|
(a) If both inputs are zero |
(b) If either or both inputs are 1 |
|
(c) Only if both input are 1 |
(d) If either input is zero |
The X-ray beam coming from an X-ray tube will be
| (a) Monochromatic |
|
(b) Having all wavelengths smaller than a certain maximum wavelength |
|
(c) Having all wavelengths larger than a certain minimum wavelength |
|
(d) Having all wavelengths lying between a minimum and a maximum wavelength |
A body can be negatively charged by
|
(a) Giving excess of electrons to it |
(b) Removing some electrons from it |
|
(c) Giving some protons to it |
(d) Removing some neutrons from it |