Two photosensitive X and Y are exposed to radiations of frequency `10^(12)Hz`. Comment on threshold frequency of each surface if photoelectrons emitted from surface X have zero kinetic energy and that from surface Y have some positive kinetic energy .

Explanation

To solve the problem, we need to analyze the situation based on the information provided about the two photosensitive surfaces, X and Y, and their interaction with the radiation of frequency \(10^{12} \text{ Hz}\).

### Step-by-Step Solution:

1. **Understand the Concept of Threshold Frequency**:
The threshold frequency (\( \nu_0 \)) is the minimum frequency of incident light required to emit photoelectrons from a material. If the frequency of the incident light is less than \( \nu_0 \), no photoelectrons will be emitted. If the frequency is equal to or greater than \( \nu_0 \), photoemission can occur.

2. **Given Information**:
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