✦ CHAPTER 1 ✦

1. Define scientific studies.

2. Why is scientific study important?

3. What are the steps involved in a scientific study?

4. What are variables?

5. Define independent variables.

6. Give an example of independent variable.

7. Give an advantage of independent variable.

8. Define dependent variables.

9. Give an example of dependent variable.

10. What are controlled variables?

11. Give an example of controlled variable.

12. Define unit.

13. Define fundamental units.

14. Define derived units.

15. What is the formula for moment of force?

16. Define physical quantity.

1 Give any two differences between fundamental and derived units.

2 Give any two differences between independent and dependent variables.

3 Give any two differences between dependent and controlled variables.

4 Write the role of controlled variables in scientific research.

5 The earth’s gravitational field intensity, g₁ = 9.81 Nkg⁻¹, is also sometimes given as the acceleration due to gravity, g = 9.8 ms⁻². show that these equations are equivalent.

6 Identify the fundamental units involved in the given physical quantities.
Power         e) Potential difference
Work done      f) Density
Moment          g) Potential energy
Electric Resistance   h) Kinetic energy

7 Prove that the unit of resistance (Ω) = kg m² s⁻³ A⁻².

8 Identify the independent, dependent and controlled variables in the experiment that is conducted to find out the use of fertilizer on the growth of the plant.

9 Write down the independent and dependent variables in the experiment that is conducted to find out the effect of sunlight on the growth of the plant.

10 Use fundamental units to show that the equation P = IV is homogeneous, where I is the electric current, V is potential difference and P is electric power.

11 Prove that the unit of potential difference (V) = kg m² s⁻³ A⁻¹.

12 Check the correctness of the equation v² = u² + 2as² by using unit wise analysis.

13 Give reason, the unit of mass is called as the fundamental unit and that of force is called as the derived unit.