Stopping Potential

Q.

In a photoelectric experiment, electrons are ejected from metals X and Y by light of intensity I and frequency f. The potential difference V required to stop the electrons is measured for various frequencies. If Y has a greater work function than X; which one of the following graphs best illustrates the expected results?

1. 

2. 

3. 

4. 

Q.

According to the classical wave picture of light, how would the current versus potential (between the plates) graph vary upon varying intensity?

1. 

2. 

3. 

4. 

Q. Photons with energy $5eV$ are incident on a cathode $C$ in a photoelectric cell. The maximum energy of emitted photo electrons is $2eV$. When photons of energy $6eV$ are incident on $C$, no photoelectrons will reach the anode $A$. The stopping potential of $A$ relative to $C$ is

1. $-3V$
2. $+3V$
3. $+4V$
4. $-1V$

Q. The maximum energy $K_{max}$ of photoelectrons emitted in a photoelectric cell is measured using lights of various frequencies $v$. The given graph shows how $K_{max}$ varies with $v$. The slope of the graph is equal to

1. the charge of an electron
2. the charge to mass ratio of an electron
3. the work function of the emitter in the cell
4. Planck's constant.

Q. The linear momentum of an electron, initially at rest, accelerated through a potential difference of 100 V is (in kg $m{s}^{-1}$)

1. $2.25\times {10}^7$
2. $5.4\times {10}^{-24}$
3. $5.4\times {10}^7$
4. $2.85\times {10}^{-24}$

Q. Assuming photoemission to take place, the factor by which the maximum velocity of the emitted photoelectrons changes when the wavelength of the incident radiation is increased four times, is

1. 4
2. $\frac{1}{4}$
3. 2
4. $\frac{1}{2}$

Q. In a photo electric emission process from a metal of work function 1.8 eV, the kinetic energy of most energetic electrons is 0.5 eV. The corresponding stopping potential is

1. 1.8 V
2. 1.3 V
3. 0.5 V
4. 2.3 V

Q.

In a photo electric experiment 4 electrons with varying kinetic energy come out.

$E_1=1.6\times {10}^{-19}J{E}_2=2.1\times {10}^{-19}J{E}_3=3.2\times {10}^{-19}J{E}_4=1.2\times {10}^{-19}J$

The stopping potential , given this data will be Volt

Q. When a point source of light is at a distance of 50 cm from a photoelectric cell, the cut off voltage is found to be $V_0$. If the same source is placed at a distance of 1 m from the cell, the cut off voltage will be

1. $\frac{V_0}{4}$
2. $\frac{V_0}{2}$
3. $V_0$
4. $2V_0$

Q. Monochromatic light of frequency ${\nu }_1$ irradiates a photocell and the stopping potential is found to be $V_1$. What is the new stopping potential of the cell if it is irradiated by monochromatic light of frequency ${\nu }_2$?

1. $V_1+\frac{h}{e}({\nu }_2-{\nu }_1)$
2. $V_1-\frac{h}{e}({\nu }_2-{\nu }_1)$
3. $V_1+\frac{h}{e}({\nu }_1+{\nu }_2)$
4. $V_1-\frac{h}{e}({\nu }_1+{\nu }_2)$

Q. Photons with energy $5eV$ are incident on a cathode $C$ in a photoelectric cell. The maximum energy of emitted photo electrons is $2eV$. When photons of energy $6eV$ are incident on $C$, no photoelectrons will reach the anode $A$. The stopping potential of $A$ relative to $C$ is

1. $-3V$
2. $+3V$
3. $+4V$
4. $-1V$

Q.

In the Photoelectric setup, I would like to achieve stopping potential by making one of the plates in the setup, positively charged. Which one should I charge positively?

1. The collector plate

2. The emitter plate

3. Stopping potential cannot be achieved by making any plate positively charged

4. More data is required to make a selection

Q. When photons of wavelength ${\lambda }_1$ are incident on a metal plate, the corresponding stopping potential is found to be $V$. When photons of wavelength ${\lambda }_2$ are used, the corresponding stopping potential was thrice the above value. If light of wavelength ${\lambda }_3$ is used, the stopping potential for wavelength ${\lambda }_3$ in terms of ${\lambda }_1$ and ${\lambda }_2$ will be

1. $\frac{hc}{e}\left(\frac{1}{{\lambda }_3}+\frac{1}{2{\lambda }_2}-\frac{1}{{\lambda }_1}\right]$
2. $\frac{hc}{e}\left(\frac{1}{{\lambda }_3}+\frac{1}{2{\lambda }_2}-\frac{3}{2{\lambda }_1}\right]$
3. $\frac{hc}{e}\left(\frac{1}{{\lambda }_3}+\frac{1}{{\lambda }_2}-\frac{1}{{\lambda }_1}\right]$
4. $\frac{hc}{e}\left(\frac{1}{{\lambda }_3}-\frac{1}{{\lambda }_2}-\frac{1}{{\lambda }_1}\right]$