Question

Guyz plz can anyone provide me the notes of topic dimensional analysis class 11th physics??​

Answer 1

Answer:

Yup mate

Explanation:

Understanding dimensions is of utmost importance as it helps us in studying the nature of physical quantities mathematically. The basic concept of dimensions is that we can add or subtract only those quantities which have same dimensions. Also, two physical quantities are equal if they have same dimensions. These basic ideas help us in deriving the new relation between physical quantities, it is just like units.

Dimensional Analysis

Use of conversion factors

Image 1: Use of conversion factors

The study of relationships between physical quantities with the help of their dimensions and units of measurements is called dimensional analysis. We use dimensional analysis in order to convert a unit from one form to another. In science and mathematical problems, we have to keep the unit same so that we can perform the mathematical operations easily.

Dimensional Analysis is also called Factor Label Method or Unit Factor Method as we use conversion factor in order to get same units. As an example, if we want to know how many minutes are in 3 hours, what do we do? We generally think as follows:

1 hour = 60 minutes

3 hour = 3 × 60 minutes = 180 minutes

(here the conversion factor 60 minutes)

We use conversion factors accordingly so that the answer comes in the desired unit and biased results are avoided.

We only unit which is asked in conversion question, i.e if the answer is asked in kg, it has to be in kg.

Image 2: We only unit which is asked in conversion question, that is, if the answer is asked in kg, it has to be in kg.

Example 1:

To find out how many kilograms are there are 52 pounds (lbs.). In this, we have to convert pounds into kilograms. Generally, 1 kg = 2.2046 lbs., we can use this figure as our conversion factor.

Now 2.2046 lbs. = 1 kg

1 lbs. = 1/2.2046 kg

Then 52 lbs. = 52 × 1/2.2046 kg

= 23.58 kg

Example 2:

To find out how many feet are in 140 centimeters (cm). In this, we have to convert centimeters into feet. Since we can’t convert centimeters directly into feet, so we will convert it into inches, and then convert inches to feet. This involves calculation of two conversion factors.

So 1 inch = 2.54 cm

1 cm = 1/2.54 inches

12 inches = 1 feet

12 × 2.54 cm = 1 feet

30.48 cm = 1 feet

1 cm = 1/30.48 feet

Then , 140 cm = 140 × 1/30.48 feet

= 4.59 feet