- AValence band is partially filled with electrons.
- BConduction band is partially filled with electrons.
- CConduction band is filled with electrons and valence band is empty.
- DConduction band is empty and valence band is filled with electrons.
Explanation:
Insulators are the materials which do not conduct electricity. All the electrons are filled in valance band whereas the conduction band is empty. Moreover, the energy band gap in insulators is very large, thus electrons cannot jump from valence band to conduction band.
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Half-life is measured by
|
(a) Geiger-Muller counter |
(b) Carbon dating |
|
(c) Spectroscopic method |
(d) Wilson-Cloud chamber |

Equal potentials are applied on an iron and copper wire of same length. In order to have the same current flow in the two wires, the ratio r (iron)/r (copper) of their radii must be (Given that specific resistance of iron =
ohm–m and specific resistance of copper = 1.7
ohm-m)
|
(a) About 1.2 |
(b) About 2.4 |
(c) About 3.6 |
(d) About 4.8 |
An NPN-transistor circuit is arranged as shown in figure. It is

|
(a) A common base amplifier circuit |
(b) A common emitter amplifier circuit |
|
(c) A common collector amplifier circuit |
(d) Neither of the above |
Assertion : The setting sun appears to be red.
Reason : Scattering of light is directly proportional to the wavelength.
|
(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. |
In which one of the following regions of the electromagnetic spectrum will the vibrational motion of molecules give rise to absorption
|
(a) Ultraviolet |
(b) Microwaves |
(c) Infrared |
(d) Radio waves |
A light wave has a frequency of 4
Hz and a wavelength of 5
meters in a medium. The refractive index of the medium is
|
(a) 1.5 |
(b) 1.33 |
(c) 1.0 |
(d) 0.66 |
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 |
