In the nuclear reaction, `{:(235),(92):}Urarr{:(207),(82):}` Pb, the number of `beta`- particles lost would be

Explanation

To determine the number of beta particles emitted in the nuclear reaction \( \text{ }^{235}_{92}\text{U} \rightarrow \text{ }^{207}_{82}\text{Pb} \), we can follow these steps:

### Step 1: Write the Nuclear Reaction
The given nuclear reaction is:
\[ \text{ }^{235}_{92}\text{U} \rightarrow \text{ }^{207}_{82}\text{Pb} + x \text{(alpha particles)} + y \text{(beta particles)} \]

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