JEE MAIN - Physics (2022 - 27th June Morning Shift - No. 22)
A beam of monochromatic light is used to excite the electron in Li+ + from the first orbit to the third orbit. The wavelength of monochromatic light is found to be x $$\times$$ 10$$-$$10 m. The value of x is ___________.
[Given hc = 1242 eV nm]
Answer
114
Explanation
E(in eV) = 13.6 $$\times$$ 9$$\left( {1 - {1 \over 9}} \right)$$
= 13.6 $$\times$$ 8 eV
$$\Rightarrow$$ $$\lambda = {{12420} \over {13.6 \times 8}}\mathop A\limits^o $$
= 114.15 $$\mathop A\limits^o $$
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