Which of the following is not the property of cathode rays:
1. | it produces a heating effect. |
2. | it does not deflect in the electric field. |
3. | it casts a shadow. |
4. | it produces fluorescence. |
J.J. Thomson's cathode-ray tube experiment
demonstrated that:
1. | cathode rays are streams of negatively charged ions |
2. | all the mass of an atom is essentially in the nucleus |
3. | the e/m of electrons is much greater than the e/m of protons |
4. | the e/m ratio of the cathode ray particles changes when a different gas is placed in the discharge tube |
A photo-cell is illuminated by a source of light, which is placed at a distance \(d\) from the cell. If the distance becomes \(\frac{d}{2}\), then the number of electrons emitted per second will be:
1. same
2. four times
3. two times
4. one-fourth
1. | work function of material | 2. | intensity of incident radiation |
3. | frequency of incident radiation | 4. | wavelength of incident radiation |
The wavelength of light in the visible region is about \(550\) nm (average wavelength) for yellow-green colour. Three materials with work functions are given as Al (\(4.28\) eV), Cu (\(4.65\) eV) and Na (\(2.75\) eV). From which of these photosensitive materials, can you build a photoelectric device that operates with visible light?
1. Al
2. Cu
3. Na
4. none of the above
According to Einstein's photoelectric equation, the graph between the kinetic energy of photoelectrons ejected and the frequency of incident radiation is:
1. | 2. | ||
3. | 4. |