Single Choice

The energy of a photon is $$3 \times 10^{-12}$$ ergs. Its wavelength (in nm) will be:

A$$662$$
Correct Answer
B$$1324$$
C$$66.2$$
D$$6.62$$

Solution

Erg is the dimension of energy in CGS (centimeter-gram-second) system of units. Therefore, $$ 1 \:\text{erg} = 10^{-7} \:\text {joules} $$. Now, the energy of photon is $$ 3 $$ x $$10^{-19} J $$. Using $$ E = \dfrac{h\times c}{\lambda} $$, $$\text{Wavelength (nm)}=\dfrac{3\times 10^8m/s\times6.626\times10^{-34} }{3\times 10^{-19}J}J\:s$$ = 662\:\text{nm}$$.

SIMILAR QUESTIONS

Atomic Structure

Calculate the de Broglie wavelength for a beam of electron whose energy is 100 eV:

Atomic Structure

If the de-Broglie wavelength of a particle of mass $$m$$ is $$100$$ times its velocity then its value in terms of its mass $$(m)$$ and Planck's constant $$(h)$$ is:

Atomic Structure

Threshold wavelength of a metal is $${\lambda}_{0}$$. The de Broglie wavelength of photoelectron when the metal is irradiated with the radiation of wavelength $$\lambda$$ is:

Atomic Structure

The de Broglie wavelength associated with a ball of mass 200 g and moving at a speed of 5 meters / hour, is of the order of ($$h= 6.625\times 10^{-34}J s $$) is:

Atomic Structure

The de Broglie wavelength of a particle of mass 1 gram and velocity $$100\ { ms }^{ -1 }$$ is:

Atomic Structure

The de Broglie wavelength of an electron in the 4th Bohr orbit is:

Atomic Structure

The de Broglie wavelength (λ) associated with a photoelectron varies with the frequency (v) of the incident radiation as, [v0 is thrshold frequency]:

Atomic Structure

The de-Broglie's wavelength of electron present in first Bohr orbit of $$'H'$$ atom is?

Atomic Structure

Photoelectrons are liberated by ultraviolet light of wavelength $$3000\mathring{A}$$ from a metallic surface for which the photoelectric threshold is $$4000\mathring{A}$$. The de-Broglie wavelength of electrons emitted with maximum kinetic energy is:

Atomic Structure

The energy of an electron having de-Broglie wavelength $$'\lambda'$$ is: [h = Planck's constant, m = mass of electron]

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