- ASilver
- BMica
- CCopper
- DSilicon
Explanation:
The resistivities of semiconductors lie between 10-6 Ωm and 104 Ωm. A semiconductor material has an electrical conductivity value falling between that of a conductor, such as metallic aluminum, and an insulator, such as wood. Silicon and germanium are typical semiconductors.
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A piece of fuse wire melts when a current of 15 ampere flows through it. With this current, if it dissipates 22.5 W, the resistance of fuse wire will be
|
(a) Zero |
(b) 10 Ω |
(c) 1 Ω |
(d) 0.10 Ω |
In a compound microscope magnification will be large, if the focal length of the eye piece is
|
(a) Large |
(b) Smaller |
|
(c) Equal to that of objective |
(d) Less than that of objective |
100 mA current gives a full scale deflection in a galvanometer of 2Ω resistance. The resistance connected with the galvanometer to convert it into a voltmeter to measure 5V is
|
(a) 98 Ω |
(b) 52 Ω |
(c) 50 Ω |
(d) 48 Ω |
In the nuclear reaction: X(n, α)
the term X will be 3
|
(a) |
(b) |
(c) |
(d) |
If 10% of a radioactive material decays in 5 days, then the amount of original material left after 20 days is approximately
|
(a) 60% |
(b) 65% |
(c) 70% |
(d) 75% |
Assertion : Diamond glitters brilliantly.
Reason : Diamond does not absorb sunlight.
|
(a) If both assertion and reason are true and the reason is the correct explanation of the assertion. |
|
(b) If both assertion and reason are true but reason is not the correct explanation of the assertion. |
|
(c) If assertion is true but reason is false. |
|
(d) If the assertion and reason both are false. |