Question
For a photosensitive surface, threshold wavelength is $\lambda_0.$ Does photoemission occur if the wavelength of radiation is (i) more than $\lambda_0$ and (ii) less than $\lambda_0?$ Justify your answer.
✓
Answer
Energy of a photon $\text{E}=\frac{\text{hc}}{\lambda}$ For emission of photoelectrons energy of a photon $\geq$ work function or wavelength of incident photon $\lambda$ should be less than threshold wavelength $\lambda_0(\text{i.e., }\lambda<\lambda_0).$
Need a full question paper?
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
Explore more
Similar questions
Find the angular separation between the consecutive bright fringes in a Young's double slit experiment with blue-green light of wavelength 500nm. The separation between the slits is 2.0 × 10-3m.
When a nucleus at rest emits a beta particle, it is found that the velocities of the recoiling nucleus and the beta particle are not along the same straight line. How can this be possible in view of the principle of conservation of momentum?
Explain the Bohr's Quantum condition of angular momentum. What will be the value of it, for the second orbit of electron?
The drift current in a p-n junction is $20.0\mu\text{A}.$ Estimate the number of electrons crossing a cross-section per second in the depletion region.
→A compound microscope forms an inverted image of an object. In which of the following cases it is kely to create difficulties?
- Looking at small germs.
- Looking at circular spots.
- Looking at a vertical tube containing some water.
Estimate the speed of vertically falling raindrops from the following data. Radius of the drops = 0.02cm, viscosity of air = 1.8 × 10-4 poise, g = 9.9m/s2 and density of water = 1000kg/m3.
Calculate the mass of 1cm3 of oxygen kept at STP.
A pivoted aluminium bar falls much more slowly through a small region containing a magnetic field than a similar bar of an insulating material. Explain.
The following figure shows the input waveforms (A, ,B) and the output waveform (Y) of a gate. Identify the gate, write its truth table and draw its logic symbol.
Explain the terms ‘depletion layer’ and ‘potential barrier’ in a p-n junction diode. How are the (a) Width of depletion layer, and (b) Value of potential barrier affected when the p-n junction is forward biased?