Which of the following properties about glass makes it suitable to be used in a liquid-glass thermometer?

Options

A. a.It has a good thermal conductivity that heat can be transferred quickly from outside to the liquid.
B. b.It is transparent so that the meniscus can be read easily.
C. c.Its thermal expansivity is much lower than that of the liquid .
D. d.All of them

Answer

To determine which properties of glass make it suitable for use in a liquid-glass thermometer, we can analyze the options provided in the question step by step.

### Step 1: Understanding the Function of a Liquid-Glass Thermometer
A liquid-glass thermometer is designed to measure temperature by observing the expansion of a liquid (usually mercury or colored alcohol) within a glass tube. As the temperature increases, the liquid expands and rises in the tube, allowing for a temperature reading.

**Hint:** Consider the basic principle of how a thermometer works.

### Step 2: Analyzing the Properties of Glass
We need to evaluate the properties of glass mentioned in the options:

- **Option A:** Good thermal conductivity.
- **Option B:** Transparency.
- **Option C:** Lower thermal expansivity than the liquid.
- **Option D:** All of the above.

**Hint:** Think about how each property affects the functioning of the thermometer.

### Step 3: Evaluating Each Option
1. **Good Thermal Conductivity (Option A):**
- While good thermal conductivity allows heat to transfer quickly, if glass expands too much with heat, it can lead to inaccurate readings. Therefore, this property is not ideal for a thermometer.

**Hint:** Consider how thermal conductivity affects the expansion of materials.

2. **Transparency (Option B):**
- Transparency is crucial because it allows the user to see the meniscus of the liquid inside the thermometer clearly for accurate readings. This property is necessary for the thermometer's functionality.

**Hint:** Why is it important to see the liquid in the thermometer?

3. **Lower Thermal Expansivity than the Liquid (Option C):**
- For accurate readings, the glass must expand less than the liquid. If the glass expands too much, it would cause the liquid level to rise less than expected, leading to incorrect temperature readings. This property is essential.

**Hint:** Think about the relationship between the expansion of the liquid and the glass.

4. **All of the Above (Option D):**
- Since Option A is not suitable, this option cannot be correct.

### Step 4: Conclusion
Based on the analysis:
- The properties that make glass suitable for use in a liquid-glass thermometer are:
- **Transparency (Option B)** - allows for easy reading of the meniscus.
- **Lower thermal expansivity than the liquid (Option C)** - ensures accurate temperature readings.

Thus, the correct answer is **B and C**.

**Final Answer:** The properties of glass that make it suitable for use in a liquid-glass thermometer are that it is transparent (B) and has a lower thermal expansivity than the liquid (C).