Explanation:
The observed spectral lines are caused by the transition of electrons between two energy levels in an atom.
The emission spectrum of the hydrogen atom is divided into many spectral series, with wavelengths that are given by Rydberg’s formula.
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Two point charges +8q and -2q are located at x = 0 and x = L respectively. The location of a point on the x-axis at which the net electric field due to these two point charges is zero is
|
(a) 8 L |
(b) 4 L |
(c) 2 L |
(d) |
An elementary particle of mass m and charge +e is projected with velocity v at a much more massive particle of charge Ze, where Z > 0. What is the closest possible approach of the incident particle
|
(a) |
(b) |
(c) |
(d) |
If 
and 
are the number of electrons and holes in a semiconductor heavily doped with phosphorus, then
|
(a) |
(b) |
(c) |
(d) |
A condenser having a capacity of 6mF is charged to 100 V and is then joined to an uncharged condenser of 14 μF and then removed. The ratio of the charges on 6mF and 14mF and the potential of 6mF will be
|
(a) |
(b) |
(c) |
(d) |
For a cell, the graph between the potential difference (V) across the terminals of the cell and the current (I) drawn from the cell is shown in the figure. The e.m.f. and the internal resistance of the cell are
|
(a) 2V, 0.5Ω |
(b) 2V, 0.4 Ω |
(c) >2V, 0.5 Ω |
(d) > 2V, 0.4 Ω |
A resistor 
dissipates the power P when connected to a certain generator. If the resistor 
is put in series with , the power dissipated by
|
(a) Decreases |
|
(b) Increases |
|
(c) Remains the same |
|
(d) Any of the above depending upon the relative values of |
Biological importance of Ozone layer is
|
(a) It stops ultraviolet rays |
|
(b) Ozone rays reduce green house effect |
|
(c) Ozone layer reflects radio waves |
|
(d) Ozone layer controls |
The phenomena involved in the reflection of radiowaves by ionosphere is similar to:
