Which one among the following shows the particle nature of light?
1. Photoelectric effect
2. Interference
3. Refraction
4. Polarization
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
A photoelectric cell is illuminated by a point source of light 1 m away. When the source is shifted to 2 m then:
1. | each emitted electron carries one-quarter of the initial energy |
2. | number of electrons emitted is half the initial number |
3. | each emitted electron carries half the initial energy |
4. | number of electrons emitted is a quarter of the initial number |
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 |
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. |
When ultraviolet rays strike a metal plate, the photoelectric effect does not occur. It occurs by the incidence of:
1. Infrared rays
2. X-rays
3. Radio wave
4. Lightwave
If particles are moving with the same velocity, then the de-Broglie wavelength is maximum for:
1. proton
2. \(\alpha-\)particle
3. neutron
4. \(\beta-\)particle
The value of Planck's constant is:
1.
2.
3.
4.
The total energy of an electron is \(3.555~\text{MeV}\). Its kinetic energy will be:
1. \(3.545~\text{MeV}\)
2. \(3.045~\text{MeV}\)
3. \(3.5~\text{MeV}\)
4. none of the above
If the K.E. of an electron and a photon is the same, then the relation between their de-Broglie wavelength will be:
1.
2.
3.
4.