Topic 1: Physical Quantities (A)

1. Express the SI base unit for electric current according to the International System of Units.

2. Identify which of the following is a fundamental (base) physical quantity: Velocity, Force, Mass, or Work.

3. ​Determine the correct dimensional formula for mechanical energy or work (ML²T⁻²)

4. Convert a speed of 72 km/h into its equivalent value in standard SI base units (m/s).

5. State the number of significant figures present in the precise scientific measurement 0.00450 m.

6. Write the prefix and symbol used to represent a multiplier of 10⁻⁹ in the metric system.

7. Perform a dimensional check to verify whether the equation v = u + at dimensionally consistent.

8. Identify the derived physical quantity represented by the unit product kg • m/s².

9. Rewrite the large numerical value 5,600,000 m. in standard scientific notation with proper significant digits.

10. Determine the fundamental dimensions (in terms of M, L, T) associated with the physical quantity of pressure. 

​1. SI Base Unit for Electric Current ​Answer: Ampere (\text{A}) ​2. Fundamental (Base) Physical Quantity ​Answer: Mass (Velocity, Force, and Work are all derived quantities). ​3. Dimensional Formula for Mechanical Energy or Work ​Answer: M L^2 T^{-2} (derived from \text{Work} = \text{Force} \times \text{Displacement} = (M L T^{-2})(L) = M L^2 T^{-2}). ​4. Speed Conversion (72\text{ km/h} to \text{m/s}) ​Answer: 20\text{ m/s} (Calculation: 72 \times \frac{5}{18} = 20\text{ m/s}) ​5. Significant Figures in 0.00450\text{ m} ​Answer: 3 significant figures (leading zeros are placeholders, while the trailing zero after the decimal is significant). ​6. Metric Prefix and Symbol for 10^{-9} ​Answer: Nano, represented by the symbol \text{n}. ​7. Dimensional Check of v = u + at ​Answer: Dimensionally consistent. ​Velocity (v and u): [L T^{-1}] ​Acceleration \times time (at): [L T^{-2}] \times [T] = [L T^{-1}] ​Since all terms share the exact same dimensions ([L T^{-1}]), the equation is valid. ​8. Derived Physical Quantity for \text{kg} \cdot \text{m} / \text{s}^2 ​Answer: Force (which is measured in Newtons, \text{N}). ​9. Scientific Notation for 5,600,000\text{ m} ​Answer: 5.6 \times 10^6\text{ m} (assuming two significant figures based on the standard presentation, or 5.60 \times 10^6\text{ m} if three are implied). ​10. Fundamental Dimensions of Pressure ​Answer: M L^{-1} T^{-2} (Pressure = \frac{\text{Force}}{\text{Area}} = \frac{M L T^{-2}}{L^2} = M L^{-1} T^{-2}) 

1. Express the SI base unit for electric current according to the International System of Units. 

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