Dual Nature of Radiation and Matter · Question 71

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

A photo-cell is illuminated by a source of light, which is placed at a distance d from the cell. If the distance becomes d/2, then number of electrons emitted per second, will be

1. remain same
2. four times
3. two times
4. one-fourth

The interplanar distance in a crystal is 2.8 10-8 m. The value of maximum wavelength which can be diffracted is

1. 2.8 10-8 m
2. 5.6 10-8 m
3. 1.4 10-8 m
4. 7.6 10-8 m

By photoelectric effect, Einstein proved

1. E = h
2. K.E. = 12 mv2
3. E = mc2
4. E = -Rhcn2