Assertion : 1 dyne = `10^(-5)` newton.
Reason : Dyne is the CGS unit of pressure while newton is the SI unit of pressure.

Options

A. If both assertion and reason are true and reason is the correct explanation of assertion.
B. If both assertion and reason are true but reason is not the correct explanation of assertion.
C. If assertion is true but reason is false.
D. If assertion is false but reason is true.

Explanation

**Step-by-Step Solution:**

1. **Understanding the Assertion**: The assertion states that "1 dyne = 10^(-5) newton". To verify this, we need to recall the definitions of dyne and newton.

2. **Definition of Dyne**: Dyne is the CGS (centimeter-gram-second) unit of force. It is defined as the force required to accelerate a mass of 1 gram at a rate of 1 cm/s².

3. **Definition of Newton**: Newton is the SI (International System of Units) unit of force. It is defined as the force required to accelerate a mass of 1 kilogram at a rate of 1 m/s².

4. **Conversion of Units**:
- 1 dyne = 1 gram × 1 cm/s²
- Since 1 gram = 10^(-3) kg and 1 cm = 10^(-2) m, we can convert dyne to newton:
\[ 1 \text{ dyne} = (10^{-3} \text{ kg}) \times (10^{-2} \text{ m/s}^2) = 10^{-5} \text{ N} \]
- Therefore, the assertion "1 dyne = 10^(-5) newton" is true.

5. **Understanding the Reason**: The reason states that "Dyne is the CGS unit of pressure while newton is the SI unit of pressure". This is incorrect because dyne is not a unit of pressure; it is a unit of force. The CGS unit of pressure is the "dyne per square centimeter" (dyn/cm²), while the SI unit of pressure is the "pascal" (N/m²).

6. **Conclusion**:
- Since the assertion is true and the reason is false, we conclude that the correct answer is option 3: "If assertion is true, but reason is false."

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