Question 71:
easyThe de-Broglie wavelength of a neutron in thermal equilibrium with heavy water at a temperature T (Kelvin) and mass m, is:
(2017-Delhi)
Practice NEET Modern Physics Questions
Question 72:
easyAn electron of mass m and a photon have same energy E. The ratio of de-Broglie wavelengths associated with them is (c being velocity of light)
(2016-I)
Question 73:
easyElectrons of mass m with de-Broglie wavelength $\lambda$ fall on the target in an X-ray tube. The cutoff wavelength ($\lambda_0$) of the emitted X-ray is:
(2016-II)
Question 74:
easyIf a photon has velocity c and frequency $\nu$, then which of the following represents its wavelength?
(1996)
The energy of a photon is $E = \frac{hc}{\lambda}$. Rearranging for wavelength gives $\lambda = \frac{hc}{E}$.
Question 75:
easyIf we consider electrons and photons of same wavelength, then they will have same
(1995)
According to the de-Broglie relation, $\lambda = \frac{h}{p}$. If the wavelength $\lambda$ is the same, then the momentum $p$ must also be the same.
Question 76:
easyMomentum of photon wavelength $\lambda$ is
(1993)
The momentum of a photon is given by $p = \frac{h}{\lambda}$. Since $c = \nu \lambda$, we can write $\lambda = \frac{c}{\nu}$. Substituting this into the momentum equation gives $p = \frac{h\nu}{c}$.
Question 77:
easyThe wavelength of a $1 keV$ photon is $1.24 \times 10^{-9} m$. What is the frequency of $1 MeV$ photon?
(1991)
Energy $E = 1 MeV = 10^6 eV$. In joules, $E = 10^6 \times 1.6 \times 10^{-19} = 1.6 \times 10^{-13} J$. Frequency $\nu = \frac{E}{h} = \frac{1.6 \times 10^{-13}}{6.63 \times 10^{-34}} \approx 2.4 \times 10^{20} Hz$.
Question 78:
easyThe momentum of a photon of an electromagnetic radiation is $3.3 \times 10^{-29} kg ms^{-1}$. What is the frequency of the associated waves? $[h = 6.6 \times 10^{-34} Js ; c = 3 \times 10^8 ms^{-1}]$
(1990)
Momentum $p = \frac{h\nu}{c}$. Frequency $\nu = \frac{pc}{h} = \frac{3.3 \times 10^{-29} \times 3 \times 10^8}{6.6 \times 10^{-34}} = \frac{9.9 \times 10^{-21}}{6.6 \times 10^{-34}} = 1.5 \times 10^{13} Hz$.
Question 79:
easyThe energy of a photon of wavelength $\lambda$ is
(1988)
The energy of a photon in terms of wavelength is given by the relation $E = \frac{hc}{\lambda}$.
Question 80:
easyThe wave nature of electrons was experimentally verified by.
(2020-Covid)
The wave nature of moving electrons was first experimentally verified by C.J. Davisson and L.H. Germer in 1927 through their electron diffraction experiment.