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Q. No.The de-Broglie wavelength associated with an electron accelerated through a potential difference \(V\) is \(\lambda_e\) \(\lambda_p.\) \(m_e\) \(m_p,\)
1. \(\sqrt{\dfrac{m_p}{m_e}} \)
2. \( \sqrt{\dfrac{m_e}{m_p}}\)
3. \(\dfrac{m_p}{m_e}\)
4. \(\left(\dfrac{m_p}{m_e}\right)^2\)
1. \(\sqrt{\dfrac{m_p}{m_e}} \)
2. \( \sqrt{\dfrac{m_e}{m_p}}\)
3. \(\dfrac{m_p}{m_e}\)
4. \(\left(\dfrac{m_p}{m_e}\right)^2\)
Subtopic: De-broglie Wavelength |
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The de-Broglie wavelength for an electron accelerated through the potential difference of \(V_1\)
1. \(4\)
2. \(3\)
3. \(2\)
4. \(1\)
1. \(4\)
2. \(3\)
3. \(2\)
4. \(1\)
Subtopic: De-broglie Wavelength |
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For a certain metal, when monochromatic light of wavelength \(\lambda\)
1. \(1\)
2. \(4\)
3. \(2\)
4. \(3\)
1. \(1\)
2. \(4\)
3. \(2\)
4. \(3\)
Subtopic: Einstein's Photoelectric Equation |
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An electron of mass \(m\) is moving in an electric field \(\vec{E}=-2 E_{0} \hat{i}\left(E_{0}=\text { constant }>0\right),\) with an initial velocity \(v_{0} \hat{i}\)
\(\left(v_{0}=\text { constant }>0\right). \text { If } \lambda_{0}=\dfrac{h}{4 m v_{{0}}},\) its de Broglie wavelength at time \(t\) is:
(\(e\) = charge of electron)
1. \(\dfrac{4 \lambda_{{0}}}{\left[1-\dfrac{E_{{0}} e}{2 m} \dfrac{t}{v_{{0}}}\right]}\)
2. \(\dfrac{4 \lambda_{0}}{\left[1+\dfrac{E_{0} e}{2 m} \dfrac{t}{v_{0}}\right]}\)
3. \(\dfrac{4 \lambda_{0}}{\left[1+\dfrac{2 E_{{0}} e}{m} \dfrac{t}{v_{{0}}}\right]}\)
4. \(\dfrac{4 \lambda_{0}}{\left[1-\dfrac{2 E_{0} e}{m} \dfrac{t}{v_{0}}\right]}\)
\(\left(v_{0}=\text { constant }>0\right). \text { If } \lambda_{0}=\dfrac{h}{4 m v_{{0}}},\) its de Broglie wavelength at time \(t\) is:
(\(e\) = charge of electron)
1. \(\dfrac{4 \lambda_{{0}}}{\left[1-\dfrac{E_{{0}} e}{2 m} \dfrac{t}{v_{{0}}}\right]}\)
2. \(\dfrac{4 \lambda_{0}}{\left[1+\dfrac{E_{0} e}{2 m} \dfrac{t}{v_{0}}\right]}\)
3. \(\dfrac{4 \lambda_{0}}{\left[1+\dfrac{2 E_{{0}} e}{m} \dfrac{t}{v_{{0}}}\right]}\)
4. \(\dfrac{4 \lambda_{0}}{\left[1-\dfrac{2 E_{0} e}{m} \dfrac{t}{v_{0}}\right]}\)
Subtopic: De-broglie Wavelength |
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Light source having wavelength \(331 ~\text {nm}\) to generate photo-electrons whose stopping potential is \(0.2~\text{V}\). The work function of the used metal in the experiment is \(\alpha \times 10^{-19} ~\text{J} .\) The value of \(\alpha\) is:
\(\left({h}=6.62 \times 10^{-34} \text{J s}, {e}=1.6 \times 10^{-19}~\text{C} \text { and } {c}=3 \times 10^8~ \text{m/s}\right)\)
1. \(3.68\)
2. \(4.68\)
3. \(5.68\)
4. \(2.68\)
\(\left({h}=6.62 \times 10^{-34} \text{J s}, {e}=1.6 \times 10^{-19}~\text{C} \text { and } {c}=3 \times 10^8~ \text{m/s}\right)\)
1. \(3.68\)
2. \(4.68\)
3. \(5.68\)
4. \(2.68\)
Subtopic: Einstein's Photoelectric Equation |
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An electron is travelling with a velocity \(v\) in free space and when it enters a medium, its velocity is reduced by \(20 \%\). The de Broglie wavelength of electron in the medium is \(\alpha \lambda_{0},\) where \(\lambda_0\)
1. \(1.20\)
2. \(1.0 \)
3. \(1.25\)
4. \(0.75\)
1. \(1.20\)
2. \(1.0 \)
3. \(1.25\)
4. \(0.75\)
Subtopic: De-broglie Wavelength |
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\(K_1\) and \(K_2\) be the maximum kinetic energies of photoelectrons emitted from a surface of a given material for the light of wavelength \(\lambda_1\) \(\lambda_2\) \(\lambda_1=2\lambda_2\)
1. \(K_2+2K_1\)
2. \(2K_2-K_1\)
3. \(K_1-2K_2\)
4. \(K_2-2K_1\)
1. \(K_2+2K_1\)
2. \(2K_2-K_1\)
3. \(K_1-2K_2\)
4. \(K_2-2K_1\)
Subtopic: Einstein's Photoelectric Equation |
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The graph shows variations of stopping potential \(V_0\) with the frequency \(\nu\) of the incident radiation for three photosensitive metals \(X_1,X_2~ \text{and} ~X_3.\) Which metal will give out electrons with greater kinetic energy, for the same wavelength of incident radiation?
1. \(X_1\)
2. \(X_2\)
3. \(X_3\)
4. All the metals will give out photo electrons with same kinetic energies.
1. \(X_1\)
2. \(X_2\)
3. \(X_3\)
4. All the metals will give out photo electrons with same kinetic energies.
Subtopic: Einstein's Photoelectric Equation |
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A light wave described by \(E = 60[\sin(3\times 10^{15})t+\sin(12\times 10^{15})t]\) (in SI units) falls on a metal surface of work function \(2.8~\text{eV}\). The maximum kinetic energy of ejected photoelectron is (approximately): (in eV)
(\(h = 6.6\times 10^{-34}~\text{J.s}~\text{and}~e = 1.6\times 10^{-19}~\text{C}\).)
1. \(5.1\)
2. \(3.8\)
3. \(6.0\)
4. \(7.8\)
(\(h = 6.6\times 10^{-34}~\text{J.s}~\text{and}~e = 1.6\times 10^{-19}~\text{C}\).)
1. \(5.1\)
2. \(3.8\)
3. \(6.0\)
4. \(7.8\)
Subtopic: Einstein's Photoelectric Equation |
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A particle having electric charge \(3\times 10^{-19}~\text{C}\) and mass \(6\times 10^{-27}~\text{kg}\) is accelerated by applying an electric potential of \(1.21~\text{V}\). Wavelength of the matter wave associated with the particle is \(\alpha\times 10^{-12}~\text{m}.\) The value of \(\alpha\) is:
(Take Planck’s constant \(= 6.6\times 10^{-34}~\text{J.s}\))
1. \(10\)
2. \(15\)
3. \(20\)
4. \(25\)
(Take Planck’s constant \(= 6.6\times 10^{-34}~\text{J.s}\))
1. \(10\)
2. \(15\)
3. \(20\)
4. \(25\)
Subtopic: De-broglie Wavelength |
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