Question

Which one of the following is used as solder in an electronic industry?

• A. Pb–Cu
• B. Cu–Sn
• C. Sn–Sb
• D. Pb–Sn

Hint:

\textbf{Pb–Sn alloy} is the traditional solder in electronics due to its low melting point and excellent conductivity.

Answer 1

The Correct Option is D

Step 1: What is Solder?
Solder is a fusible metal alloy used to join metal surfaces, especially in electronic circuit boards. It must have: - A low melting point, - Good electrical conductivity, - Strong adhesion properties. Step 2: Lead-Tin (Pb–Sn) Alloy in Electronics
The most widely used solder alloy in traditional electronics is Pb–Sn, typically in the ratio 60:40 or 63:37. This alloy: - Melts at around 183–190°C, - Offers excellent wetting and adhesion on copper pads, - Has good mechanical strength and fatigue resistance. Step 3: Evaluation of Other Options
- Pb–Cu: Not a typical soldering alloy.
- Cu–Sn (bronze): Used in structural alloys, not as solder.
- Sn–Sb: Used in some high-temperature solders, but not common in general electronic applications. Conclusion: The standard and widely used solder alloy in the electronic industry is Pb–Sn.