Question

The stopping potential for a certain photosensitive metal is Vo when the frequency of incident
radiation is fo. When the frequency of the incident radiation is 8fo, what will be the stopping
potential? (given wo is workfunction of the metal).​

Answer 1

Answer:

Given

a

2

=13 and a

5

=25

We know that

a

n

=a+(n−1)d

∴a

2

=a+(2−1)d

⇒13=a+(2−1)d

⇒a+d=13 ...(i)

and a

5

=a+(5−1)d

⇒25=a+4d

⇒a+4d=25 ...(ii)

Now, subtracting (i) from (ii), we get

3d=12

⇒d=4

Now a+d=13 [from (i)]

⇒a=9

Hence, a

7

=a+6d=9+6(4)

⇒a

7

=33