Dual Nature of Radiation and Matter · Question 11

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

When two monochromatic lights of frequency, and 2 are incident on a photoelectric metal, their stopping potential becomes Vs2 and Vs respectively. The threshold frequency for this metal is

1. 2
2. 3
3. 23
4. 32

The graph which shows the variation of the de Broglie wavelength ( ) of a particle and its associated momentum (p) is

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

The light rays having photons of energy 4.2 eV are falling on a metal surface having a work function of 2.2 eV. The stopping potential of the surface is

1. 6.4 V
2. 2 eV
3. 2 V
4. 1.1 V

The threshold frequency of a photoelectric metal is 0. If light of frequency 4 0 is incident on this metal, then the maximum kinetic energy of emitted electrons will be :

1. 4h 0
2. h 0
3. 2h 0
4. 3h 0

The number of photons per second on an average emitted by the source of monochromatic light of wavelength 600 nm, when it delivers the power of 3.3 10-3 watt will be : (h = 6.6 10-34 J s)

1. 1015
2. 1018
3. 1017
4. 1016

An electromagnetic wave of wavelength ' ' is incident on a photosensitive surface of negligible work function. If 'm' mass is of photoelectron emitted from the surface has de-Broglie wavelength d, then :

1. = ( 2hmc ) d2
2. = ( 2mhc ) d2
3. d = ( 2mch ) 2
4. = ( 2mch ) d2

Light of frequency 1.5 times the threshold frequency is incident on a photosensitive material. What will be the photoelectric current if the frequency is halved and intensity is doubled?

1. four times
2. one-fourth
3. zero
4. doubled

The energy required to break one bond in DNA is 10-20 J. This value in eV is nearly :

1. 0.6
2. 0.06
3. 0.006
4. 6