Dual Nature of ...

Minimum wavelength for transition in visible region for $$Li^{2+}$$ will be given by $$(R_H\longrightarrow Rydberg's Constant)$$

The wavelength of the radiation emitted,when in a hydrogen atom electron falls from infinity to stationary state 1,would be (Rydberg constant=$$1.097 \times 10^{7}m^{-1}$$

An electron has kinetic energy $$2.8 \times 10^{-23}$$j. de-Broglie wavelength will be nearly:
$$(m_e=9.1 \times 10^{-31}kg)$$

Based on the equation
$$\triangle E=-2.0\times 10^{-18}J(\cfrac 1 {n_2^2}-\cfrac1 {n_1^2})$$
  the wavelength of the light that must be absorbed to excite hydrogen electron from level $$n=1 \quad to\quad level\quad n=2 \quad will\quad  be(h=6.625 \times 10^{-34}Js,C=3 \times 10^8ms^{-1})$$

 If the radius of first orbit  of $$H$$ atom is $${a_ \circ }$$ the de-Broglie wavelength of an electron in the third orb is :

If $$E_{e},E_{a},$$ and $$E_{p}$$ represents the kinetic energy of an electron,$$\alpha$$-particle and proton respectively each moving with same de-broglie wavelength then:

A bulb of 40 W is producing a light of wavelength 620 mm with $$60\%$$ of  efficiency then the number of photons emitted by the bulb in 20 seconds are (1 eV=$$16\times10^{-19}$$,J, hc=12400 eV A)

What is wavelength associated with $$150$$ $$eV$$ electron?

An electron falls from rest through a potential difference of $$100\ V$$. What is its de Brogile wavelength ?

Calculate the wavelength of spectral line of the strongest wavelength in Balmer seres of hydrogen