Question

The figure shows the variation of photo current with anode potential for a photo-sensitive surface for three different radiations. Let and $I _ { c }$ be the intensities and $v _ { a } , v _ { b }$ and be the frequencies of the curves a, b and c respectively.

• A. $\mathrm { v } _ { \mathrm { a } } = \mathrm { v } _ { \mathrm { b } }$ and
• B. $\mathrm { v } _ { \mathrm { a } } = \mathrm { v } _ { \mathrm { b } }$ and $I _ { a } \neq I _ { c }$
• C. $\mathrm { v } _ { \mathrm { a } } = \mathrm { v } _ { \mathrm { b } }$ and
• D. and

Answer 1

Answer: (A)

$\mathrm { v } _ { \mathrm { a } } = \mathrm { v } _ { \mathrm { b } }$ and

Answer 2

: From the graph, we note that the saturation current is same for curves b and c but different for curve a. therefore intensities of b and c will be equal but different from that of a i.e. $I _ { a } \neq I _ { b }$ but $I _ { b } = I _ { c }$As stopping potential is same for curves a and b hence $v _ { a } = v _ { b }$ thus answer (1) is correct