- AMetals
- BSuper conductors
- CInsulators
- DSemiconductors
Explanation:
In insulators, the electrons are tightly bound with the nucleus hence, at room temperature thermal energy is not enough to push the electrons into conduction band and hence, no electrons are available for conduction.
The energy required for electron to escape out from orbit and to over come the energy gap is thus of the order of 6 eV, while for semiconductors and conductors it is (of the order of) 1 eV and 0 respectively.
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
When yellow light is incident on a surface, no electrons are emitted while green light can emit. If red light is incident on the surface, then
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(a) No electrons are emitted |
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(b) Photons are emitted |
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(c) Electrons of higher energy are emitted |
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(d) Electrons of lower energy are emitted |
A and B are two radioactive substances whose half lives are 1 and 2 years respectively. Initially 10 gm of A and 1 gm of B is taken. The time (approximate) after which they will have same quantity remaining is
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(a) 6.62 years |
(b) 5 years |
(c) 3.2 years |
(d) 7 years |
A 10 μF capacitor is charged to a potential difference of 50 V and is connected to another uncharged capacitor in parallel. Now the common potential difference becomes 20 volt. The capacitance of second capacitor is
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(a) 10 μF |
(b) 20 μF |
(c) 30 μF |
(d) 15 μF |
A person cannot see objects clearly beyond 2.0 m. The power of lens required to correct his vision will be
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(a) + 2.0 D |
(b) – 1.0 D |
(c) + 1.0 D |
(d) – 0.5 D |
Two long parallel wires are at a distance 2d apart. They carry steady equal currents flowing out of the plane of the paper, as shown. The variation of the magnetic field B along the line XX’ is given by
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(a) |
(b) |
(c) |
(d) |