Dual Nature of Radiation and Matter · Question 68

The work functions for metals A, B and C are respectively 1.92 eV, 2.0 eV and 5 eV. According to Einstein's equation the metals which will emit photoelectrons for a radiation of wavelength 4100 A is/are

1. A only
2. A and B only
3. all the three metals
4. none

A photosensitive metallic surface has work function, h 0. If photons of energy 2h 0 fall on this surface, the electrons come out with a maximum velocity of 4 106 m/s. When the photon energy is increased to 5h 0, then maximum velocity of photoelectrons will be

1. 2 107 m/s
2. 2 106 m/s
3. 8 106 m/s
4. 8 105 m/s

According to Einstein's photoelectric equation, the graph between the kinetic energy of photoelectrons ejected and the frequency of incident radiation is

1. [figure]
2. [figure]
3. [figure]
4. [figure]

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

The value of Planck's constant is

1. 6.63 10-34 J/sec.
2. 6.63 10-34 kg-m2/sec2
3. 6.63 10-34 kg-m2
4. 6.63 10-34 J-sec.

If particles are moving with same velocity, then which has maximum de Broglie wavelength?

1. proton
2. -particle
3. neutron
4. -particle

When ultraviolet rays are incident on a metal plate, photoelectric effect does not occur. It occurs by incidence of

1. infrared rays
2. X-rays
3. radio waves
4. microwaves

Which of the following is not the property of cathode rays?

1. It produces heating effect
2. It does not deflect in electric field
3. It casts shadow
4. It produces fluorescence.

Which one among the following shows particle nature of light?

1. photoelectric effect
2. interference
3. refraction
4. polarization