Dual Nature of Radiation and Matter

A sub-atomic particle of mass 10-30 kg is moving with a velocity 2.21 106 m/s. Under the matter wave consideration, the particle will behave closely like (h=6.63 10-34 J.s )

1. X-rays
2. Infra-red radiation
3. Gamma rays
4. Visible radiation

In photoelectric effect an em-wave is incident on a metal surface and electrons are ejected from the surface. If the work function of the metal is 2.14 eV and stopping potential is 2 V, what is the wavelength of the em-wave? (Given hc=1242 eV nm where h is the Planck's constant and c is the speed of light in vacuum.)

1. 400 nm
2. 600 nm
3. 300 nm
4. 200 nm

The work functions of cesium (Cs) and lithium (Li) metals are 1.9 eV and 2.5 eV , respectively. If we incident a light of wavelength 550 nm on these two metal surfaces, then photo-electric effect is possible for the case of

1. Both Cs and Li
2. Neither Cs nor Li
3. Li only
4. Cs only

A light source of wavelength illuminates a metal surface and electrons are ejected with maximum kinetic energy of 2 eV . If the same surface is illuminated by a light source of wavelength 2, then the maximum kinetic energy of ejected electrons will be (The work function of metal is 1 eV )

1. 5 eV
2. 3 eV
3. 2 eV
4. 6 eV

A proton, an electron and an alpha particle have the same energies. Their de-Broglie wavelengths will be compared as :

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

UV light of 4.13 eV is incident on a photosensitive metal surface having work function 3.13 eV. The maximum kinetic energy of ejected photoelectrons will be:

1. 4.13 eV
2. 1 eV
3. 7.26 eV
4. 3.13 eV

A proton and an electron are associated with same de-Broglie wavelength. The ratio of their kinetic energies is: (Assume h = 6.63 10-34 J s, me = 9.0 10-31 kg and mp = 1836 times me)

1. 1 : 11836
2. 1 : 1836
3. 1 : 1836
4. 1 : 1 1836

A proton and an electron have the same de Broglie wavelength. If Kp and Ke be the kinetic energies of proton and electron respectively, then choose the correct relation :

1. Kp > Ke
2. Kp = Ke
3. Kp < Ke
4. Kp = Ke2

Which of the following phenomena is not explained by wave nature of light? Choose the most appropriate answer from the options given below:

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

In photoelectric experiment energy of 2.48 eV irradiates a photo sensitive material. The stopping potential was measured to be 0.5 V. Work function of the photo sensitive material is :

1. 1.98 eV
2. 1.68 eV
3. 2.48 eV
4. 0.5 eV

When UV light of wavelength 300 nm is incident on the metal surface having work function 2.13 eV, electron emission takes place. The stopping potential is : (Given hc = 1240 eV nm)

1. 4 V
2. 2 V
3. 4.1 V
4. 1.5 V

Given below are two statements : [figure] In the light of the above statements, choose the most appropriate answer from the options given below.

1. Statement I is correct and Statement II is incorrect
2. Statement I is incorrect but Statement II is correct
3. Both Statement I and Statement II are correct
4. Both Statement I and Statement II are incorrect

Which of the following statement is not true about stopping potential (V0) ?

1. It depends upon frequency of the incident light.
2. It is 1/e times the maximum kinetic energy of electrons emitted.
3. It increases with increase in intensity of the incident light.
4. It depends on the nature of emitter material.

Which figure shows the correct variation of applied potential difference (V) with photoelectric current (I) at two different intensities of light (I1<I2) of same wavelengths :

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

Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R. In the light of the above statements, choose the most appropriate answer from the options given below:

1. A is not correct but R is correct.
2. A is correct but R is not correct.
3. Both A and R are correct and R is the correct explanation of A.
4. Both A and R are correct and R is NOT the correct explanation of A.

The de Broglie wavelengths of a proton and an particle are and 2 respectively. The ratio of the velocities of proton and particle will be :

1. 8:1
2. 1:2
3. 1:8
4. 4:1

Monochromatic light of frequency 6 1014 Hz is produced by a laser. The power emitted is 2 10-3 W. How many photons per second on an average, are emitted by the source ? (Given h=6.63 10-34 Js)

1. 5 1015
2. 7 1016
3. 6 1015
4. 9 1018

When a metal surface is illuminated by light of wavelength , the stopping potential is 8 V. When the same surface is illuminated by light of wavelength 3 , stopping potential is 2 V. The threshold wavelength for this surface is:

1. 3
2. 9
3. 5
4. 4.5

In a photoelectric effect experiment a light of frequency 1.5 times the threshold frequency is made to fall on the surface of photosensitive material. Now if the frequency is halved and intensity is doubled, the number of photo electrons emitted will be:

1. doubled
2. halved
3. Zero
4. quadrupled

The work function of a substance is 3.0 eV. The longest wavelength of light that can cause the emission of photoelectrons from this substance is approximately;

1. 215 nm
2. 400 nm
3. 414 nm
4. 200 nm

For the photoelectric effect, the maximum kinetic energy (Ek) of the photoelectrons is plotted against the frequency ( ) of the incident photons as shown in figure. The slope of the graph gives [figure]

1. Planck's constant
2. Work function of the metal
3. Charge of electron
4. Ratio of Planck's constant to electric charge

The de-Broglie wavelength of an electron is the same as that of a photon. If velocity of electron is 25\% of the velocity of light, then the ratio of K.E. of electron and K.E. of photon will be:

1. 14
2. 81
3. 18
4. 11

Two sources of light emit with a power of 200 W. The ratio of number of photons of visible light emitted by each source having wavelengths 300 nm and 500 nm respectively, will be :

1. 5:3
2. 3:5
3. 1:5
4. 1:3

A convex lens of focal length 40 cm forms an image of an extended source of light on a photoelectric cell. A current I is produced. The lens is replaced by another convex lens having the same diameter but focal length 20 cm. The photoelectric current now is :

1. I2
2. 4 I
3. 2 I
4. I

The threshold frequency of a metal with work function 6.63 eV is :

1. 16 1015 Hz
2. 16 1012 Hz
3. 1.6 1015 Hz
4. 1.6 1012 Hz