Chapter 2

The ratio of slopes of \(K_{\max }\) vs. \(v\) and \(V_{0}\) vs. \(v\) curves in the photoelectric effect gives \((v=\) frequency, \(K_{\max }=\) maximum kinetic energy, \(V_{0}=\) stopping potential): (a) charge of electron (b) Planck's constant (c) work function (d) the ratio of Planck's constant of electronic charge

Radiation corresponding to the transition \(n=4\) to \(n=2\) in hydrogen atoms falls on a certain metal (work function \(=2.5 \mathrm{eV}\) ). The maximum kinetic energy of the photo-electrons will be: (a) \(0.55 \mathrm{eV}\) (b) \(2.55 \mathrm{eV}\) (c) \(4.45 \mathrm{eV}\) (d) None of these

Select the incorrect statement: (a) K.E. of photo-electron does not depend upon the wavelength of incident radiation (b) Photoelectric current depends on intensity of incident radiation and not on frequency (c) Stopping potential depends on frequency of radiation and not on intensity (d) None of these

Which is the de-Broglie equation: (a) \(h=p \lambda\) (b) \(h=p \lambda^{-1}\) (c) \(h=\lambda p^{-1}\) (d) \(h=p+\lambda\)

Which of the following has the largest de Broglie wavelength (all have equal velocity) (a) \(\mathrm{CO}_{2}\) molecule (b) \(\mathrm{NH}_{3}\) molecule (c) Electron (d) Proton

Which of the following electron transitions in a hydrogen atom will require the largest amount of energy? (a) from \(n=1\) to \(n=2\) (b) from \(n=2\) to \(n=4\) (c) from \(n=5\) to \(n=1\) (d) from \(n=3\) to \(n=5\)

If \(a_{0}\) be the radius of first Bohr's orbit of \(\mathrm{H}\) -atom, the de- Broglie's wavelength of an electron revolving in the second Bohr's orbit will be : (a) \(6 \pi a_{0}\) (b) \(4 \pi a_{0}\) (c) \(2 \pi a_{0}\) (d) None of these

Which electronic transition in a hydrogen atom, starting from the orbit \(n=7\), will produce infrared light of wavelength \(2170 \mathrm{~nm}\) ? (Given : \(R_{H}=1.09677 \times 10^{7} \mathrm{~m}^{-1}\) ) (a) \(n=7\) to \(n=6\) (b) \(n=7\) to \(n=5\) (c) \(n=7\) to \(n=4\) (d) \(n=7\) to \(n=3\)

Which of the following relates to photons both as wave motion and as a stream of particles? (a) Interference (b) \(E=m c^{2}\) (c) Diffraction (d) \(E=h v\)

Electromagnetic radiation (photon) with highest wavelength results when an electron in the hydrogen atom falls from \(n=6\) to : (a) \(n=1\) (b) \(n=2\) (c) \(n=3\) (d) \(n=5\)