The rays parallel and close to the principal axis are called:
- AConverging rays
- BDiverging rays
- CCoherent rays
- DParaxial rays
The rays parallel and close to the principal axis are called:
Explanation:
The rays parallel and close to the principal axis are called paraxial rays. The rays parallel but not close to the principal axis are called peripheral rays.

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Ionization energy of hydrogen is 13.6 eV. If h = 6.6
, the value of R will be of the order of
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(a) |
(b) |
(c) |
(d) |
Pick out the wrong statement
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(a) In a simple battery circuit, the point of lowest potential is the negative terminal of the battery |
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(b) The resistance of an incandescent lamp is greater when the lamp is switched off |
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(c) An ordinary 100 W lamp has less resistance than a 60 W lamp |
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(d) At constant voltage, the heat developed in a uniform wire varies inversely as the length of the wire used |