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Question
If the frequency of light in a photoelectric experiment is doubled, the stopping potential will ______.
Options
be doubled
be halved
become more than double
become less than double
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Solution
If the frequency of light in a photoelectric experiment is doubled, the stopping potential will become more than double.
Explanation:
According to Einstein's equation of the photoelectric effect,
`eV_0 = hv - varphi`
⇒ `V_0 = (hv - varphi)/e` ....(1)
Here, V0 = stopping potential
v = frequency of light
`varphi` = work function
Let the new frequency of light be 2ν and the corresponding stopping potential be V0'.
Therefore,
`eV_0^' = 2hv - varphi`
`V_0^' = (2hv - varphi)/e` ....(2)
Multiplying both sides of equation (1) by 2, we get:
`2V_0 = (2hv - 2varphi)/e` ....(3)
Now if we compare (2) and (3), it can be observed that: `(2hv - varphi)/e > (2hv - 2varphi)/e`
⇒ `V_0^' > 2V_0`
It is clear from the above equation that if the frequency of light in a photoelectric experiment is doubled, the stopping potential will be more than doubled.
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