Question: Assertion (A) : Silicon is preferred over germanium for making semiconductor devices. Reason (R) : The energy gap for germanium is more than the energy gap for silicon.

Step 1 (Governing Principle): [0.25 Mark]
The suitability of a semiconductor material for electronic devices is governed by its band gap energy ($E_g$) and its thermal stability. Silicon ($Si$) has a band gap of approximately $1.1 \text{ eV}$, whereas Germanium ($Ge$) has a band gap of approximately $0.7 \text{ eV}$.

Step 2 (Logical Analysis): [0.5 Mark]

• Assertion (A): Silicon is indeed preferred because it has a higher thermal stability and a lower leakage current compared to Germanium, making it more reliable for high-temperature operations.
• Reason (R): The energy gap for Silicon ($E_{g, Si} \approx 1.1 \text{ eV}$) is greater than the energy gap for Germanium ($E_{g, Ge} \approx 0.7 \text{ eV}$). Therefore, the statement in the Reason is factually incorrect.

Step 3 (Final Concluded Answer): [0.25 Mark]
Assertion (A) is true, but Reason (R) is false.

💡 EL10 Concept Insight: Think of the energy gap as a "security gate" for electrons; Silicon has a higher gate, which means it doesn't let stray electrons jump through accidentally when it gets hot, making it much more stable and reliable than Germanium.