Dual Nature of Radiation and Matter

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