Assertion (A): Fuse wire is made up of an alloy constituted of lead and tin in 1 : 1 ratio by mass.
Reason (R): Both lead and tin have comparatively lower melting points than other metals.

Options

A. Both (A) and (R) are true and (R) is the correct reason of (A).
B. Both (A) and (R) are true but (R) is not the correct explanation of (A).
C. (A) is true but (R) is false.
D. (A) is false but (R) is true

Explanation

**Step-by-Step Solution:**

1. **Understanding the Assertion**: The assertion states that fuse wire is made of an alloy of lead and tin in a 1:1 ratio by mass. This means that for every part of lead, there is an equal part of tin.

2. **Verifying the Assertion**: We know that fuse wires are indeed made from an alloy of lead and tin, commonly in equal proportions. This is because the properties of this alloy allow it to melt easily when a high current flows through it, thus breaking the circuit. Therefore, the assertion is correct.

3. **Understanding the Reason**: The reason given is that both lead and tin have comparatively lower melting points than other metals. This is significant because the purpose of a fuse wire is to melt and break the circuit when the current exceeds a safe level.

4. **Verifying the Reason**: Lead has a melting point of about 327.5°C and tin has a melting point of about 231.9°C, which are indeed lower than many other metals. This characteristic is essential for the functionality of a fuse wire, as it needs to melt quickly to prevent damage to electrical appliances. Thus, the reason is also correct.

5. **Connecting Assertion and Reason**: The reason explains why the assertion is true. The low melting points of lead and tin are the reason why they are used in making fuse wires. Therefore, the reason supports the assertion effectively.

6. **Conclusion**: Since both the assertion and the reason are true and the reason correctly explains the assertion, we can conclude that the correct answer is that both assertion and reason are true, and the reason is the correct explanation of the assertion.

**Final Answer**: Both assertion and reason are true, and reason is the correct explanation of assertion.

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