Which of the following statement are correct?

Options

A. The value of absolute zero on kelvin scale is zero
B. The value of absolute zero on reaumur scale is `-218.5^(@)`
C. If the difference of two temperature on celsium scale is `45^(@)`, the difference on fahrenheit scale is `81^(@)`
D. if the difference of two temperature on celsius scale is `45^(@)`, the difference in kelvin scale is `45^(@)`

Answer

To determine which of the statements are correct, let's analyze each option step by step.

### Step 1: Evaluate Option 1
**Statement**: The value of absolute zero on the Kelvin scale is zero.

**Analysis**:
- Absolute zero is defined as the point at which all molecular motion stops, and it is represented as 0 Kelvin (K).
- Therefore, this statement is correct.

### Step 2: Evaluate Option 2
**Statement**: The value of absolute zero on the Riemann scale is -218.5 degrees.

**Analysis**:
- The relationship between Celsius (C) and Riemann (R) scales is given by the formula: \( \frac{C}{5} = \frac{R}{4} \).
- Absolute zero in Celsius is -273.15 °C.
- To convert this to Riemann, we can use the formula:
\[ C = -273.15 \Rightarrow R = \frac{4}{5} \times (-273.15) = -218.52 \text{ (approximately)} \]
- Thus, the statement is correct.

### Step 3: Evaluate Option 3
**Statement**: If the difference of two temperatures on the Celsius scale is 45 degrees, the difference on the Fahrenheit scale is 81 degrees.

**Analysis**:
- The relationship between Celsius (C) and Fahrenheit (F) is given by the formula:
\[ F = \frac{9}{5}C + 32 \]
- The change in Fahrenheit for a change in Celsius can be calculated as:
\[ \Delta F = \frac{9}{5} \Delta C \]
- If \( \Delta C = 45 \):
\[ \Delta F = \frac{9}{5} \times 45 = 81 \]
- Therefore, this statement is also correct.

### Step 4: Evaluate Option 4
**Statement**: If the difference of two temperatures on the Celsius scale is 45 degrees, the difference on the Kelvin scale is 45 degrees.

**Analysis**:
- The relationship between Celsius (C) and Kelvin (K) is:
\[ K = C + 273.15 \]
- The difference in temperature (ΔC) is equal to the difference in Kelvin (ΔK) because the offset (273.15) does not affect the difference:
\[ \Delta K = \Delta C \]
- Therefore, if \( \Delta C = 45 \), then \( \Delta K = 45 \) as well.
- Thus, this statement is also correct.

### Conclusion
All four options are correct.