Dual Nature of Radiation and Matter · Question 3

A beam of light falls on a metal surface such that photo-electrons are generated. If power of the light source starts to decrease linearly with time t, then variation of the photocurrent I and magnitude of the stopping potential |V| with time is best represented by:

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

A ray of light with wavelength is incident on three different photoelectric cells namely 1, 2 and 3. The threshold wavelength of these photoelectric cells are 1, 2, and 3, respectively and the magnitude of stopping potentials of these cells are V1, V2 and V3, respectively. The relation between and threshold wavelengths are 1 < , 2 > and 3 . The correct option is:

1. V1 < V2, V3 = 0
2. V1 = 0, V2 < V3
3. V1 = 0, V2 > V3
4. V1 > V2, V3 = 0

Which of the following options represent the variation of photoelectric current with property of light shown on the x-axis? [figure]

1. A and D
2. B and D
3. A only
4. A and C

A photon and an electron (mass m) have the same energy E. The ratio ( photon/ electron) of their de Broglie wavelengths is: (c is the speed of light)

1. c 2mE
2. 1c E/2m
3. E/2m
4. c 2mE

The graph which shows the variation of ( 1 2 ) and its kinetic energy, E is (where is de Broglie wavelength of a free particle):

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

If c is the velocity of light in free space, the correct statements about photon among the following are: Choose the correct answer from the options given below:

1. A and B only
2. A, B, C and D only
3. A, C and D only
4. A, B, D and E only

An electron and an alpha particle are accelerated by the same potential difference. Let e and denote the de-Broglie wavelengths of the electron and the alpha particle, respectively, then:

1. e >
2. e = 4
3. e =
4. e <

If is the work function of photosensitive material in eV and light of wavelength of numerical value = hce metre, is incident on it with energy above its threshold value at an instant then the maximum kinetic energy of the photo-electron ejected by it at that instant (Take h-Planck's constant, c-velocity of light in free space) is (in SI units):

1. e + 2
2. 2e -
3. e - e
4. e +

The work functions of Caesium (Cs), potassium (K) and sodium (Na) are 2.14 eV, 2.30 eV and 2.75 eV respectively. If incident electromagnetic radiation has an incident energy of 2.20 eV, which of these photosensitive surfaces may emit photoelectrons?

1. Both Na and K
2. K only
3. Na only
4. Cs only

The minimum wavelength of X-rays produced by an electron accelerated through a potential difference of V volts is proportional to :

1. 1V
2. 1 V
3. V2
4. V