Question

Short Answer the following :- Any 5]
1. Briefly explain the types of physical quantities.
2. Write the rules for determining significant figures
3. What are the limitations of dimensional analysis?
4. Define precision and accuracy. Explain with one e
5. Define a vector. Give examples​

Answer 1

1. Physical quantities are classified into two types. There are fundamental and derived quantities. Fundamental or base quantities are quantities which cannot be expressed in terms of any other physical quantities. These are length, mass, time, electric current, temperature, luminous intensity and amount of substance. Quantities that can be expressed in terms of fundamental quantities are called derived quantities. For example, area, volume, velocity, acceleration, force.
2. To determine the number of significant figures in a number use the following 3 rules:

• Non-zero digits are always significant
• Any zeros between two significant digits are significant
• A final zero or trailing zeros in the decimal portion ONLY are significant

3. Limitations of a Dimensional Analysis

• To check the correctness of a physical equation.
• To derive the relation between different physical quantities involved in a physical phenomenon.
• To change from one system of units to another.

4. Accuracy refers to the closeness of a measured value to a

standard or known value. Precision refers to the closeness of two

or more measurements to each other. Using the example above, if

you weigh a given substance five times, and get 3.2 kg each time,

then your measurement is very precise.

5. A vector is a quantity or phenomenon that has two independent

properties: magnitude and direction. The term also denotes the

mathematical or geometrical representation of such a quantity.

Examples of vectors in nature are velocity, momentum, force,

electromagnetic fields, and weight.