When the light source is kept 20 cm away from a photo cell, stopping potential 0.6 V is obtained. When source is kept 40 cm away, the stopping potential will be 
1. 0.3 V                  2. 0.6 V
3. 1.2 V                  4. 2.4 V

The minimum energy required to remove an electron is called 
(1) Stopping potential               

(2) Kinetic energy

(3) Work function                     

(4) None of these

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) $\frac{1}{2}$

If the work function of a metal is $\text{'}\mathrm{\varphi }\text{'}$ and the frequency of the incident light is '$\nu$', there is no emission of photoelectron if
(1) $\mathrm{v}<\frac{\mathrm{\varphi }}{\mathrm{h}}$                   

(2) $\mathrm{v}=\frac{\mathrm{\varphi }}{\mathrm{h}}$   

(3) $\mathrm{v}>\frac{\mathrm{\varphi }}{\mathrm{h}}$                   

(4) $\mathrm{v}>=\frac{\mathrm{\varphi }}{\mathrm{h}}$   

Light of wavelength $\mathrm{\lambda }$ strikes a photo-sensitive surface and electrons are ejected with kinetic energy E. If the kinetic energy is to be increased to 2E, the wavelength must be changed to $\mathrm{\lambda }\text{'}$ where 
(1) $\mathrm{\lambda }\text{'}=\frac{\mathrm{\lambda }}{2}$           

(2) $\mathrm{\lambda }\text{'}=2\mathrm{\lambda }$

(3) $\frac{\mathrm{\lambda }}{2}<\mathrm{\lambda }\text{'}<\mathrm{\lambda }$      

(4) $\mathrm{\lambda }\text{'}>\mathrm{\lambda }$

If in a photoelectric experiment, the wavelength of incident radiation is reduced from 6000 Å to 4000 Å, then:

The photoelectric work function for a metal surface is 4.125 eV. The cut-off wavelength for this surface is

(1) 4125 Å                 

(2) 2062.5 Å

(3) 3000 Å                 

(4) 6000 Å

As the intensity of incident light increases,

Which of the following is dependent on the intensity of incident radiation in a photoelectric experiment

(1) Work function of the surface

(2) Amount of photoelectric current

(3) Stopping potential

(4) Maximum kinetic energy of photoelectrons

The work function of a substance is 4.0 eV. The longest wavelength of light that can cause photoelectron emission from this substance is approximately

(1) 540 nm                 

(2) 400 nm

(3) 310 nm                 

(4) 220 nm