The number of photons per second on an average emitted by a source of monochromatic light of wavelength \(600~\text{nm}\), when it delivers the power of \(3.3\times 10^{-3}\) watt will be:
\((h = 6.6\times10^{-34}~\text{J-s})\)
1. | \(10^{16}\) | 2. | \(10^{15}\) |
3. | \(10^{18}\) | 4. | \(10^{17}\) |
An electromagnetic wave of wavelength \(\lambda\) is incident on a photosensitive surface of negligible work function. If '\(m\)' is the mass of photoelectron emitted from the surface and \(\lambda_d\) is the de-Broglie wavelength, then:
1. \( \lambda=\left(\frac{2 {mc}}{{h}}\right) \lambda_{{d}}^2 \)
2. \( \lambda=\left(\frac{2 {h}}{{mc}}\right) \lambda_{{d}}^2 \)
3. \( \lambda=\left(\frac{2 {m}}{{hc}}\right) \lambda_{{d}}^2\)
4. \( \lambda_{{d}}=\left(\frac{2 {mc}}{{h}}\right) \lambda^2 \)
An electron is accelerated from rest through a potential difference of \(V\) volt. If the de Broglie wavelength of an electron is \(1.227\times10^{-2}~\text{nm}\). what will be its potential difference?
1. \(10^{2}~\text{V}\)
2. \(10^{3}~\text{V}\)
3. \(10^{4}~\text{V}\)
4. \(10^{5}~\text{V}\)
1. | four times | 2. | one-fourth |
3. | zero | 4. | doubled |
1. | \(\dfrac{3}{2} \nu\) | 2. | \(2\nu\) |
3. | \(3\nu\) | 4. | \(\dfrac{2}{3} \nu\) |
1. | 2. | ||
3. | 4. |
The de-Broglie wavelength of the thermal electron at \(27^\circ \text{C}\) is \(\lambda.\) When the temperature is increased to \(927^\circ \text{C},\) its de-Broglie wavelength will become:
1. \(2\lambda\)
2. \(4\lambda\)
3. \(\frac\lambda2\)
4. \(\frac\lambda4\)
In a photoelectric experiment, blue light is capable of ejecting a photoelectron from a specific metal while green light is not able to eject a photoelectron. Ejection of photoelectrons is also possible using light of the colour:
1. yellow
2. red
3. violet
4. orange
1. | \(2~\text{eV}\) | 2. | \(2~\text{V}\) |
3. | \(1.1~\text{V}\) | 4. | \(6.4~\text{V}\) |