Question

Class 11 ¦¦ ✨
Units and measurements ¦¦✨
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¦¦¦ Refer the above attachment¡!
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Thank you ☺♥

Answer 1

1- While taking measurements, we are never able to find an accurate value of something. The measurement always has a difference from the true value.
This difference in the true value and measured value of a quantity is called error.

2- The types of error and their formulae are given in the picture.

3- Accuracy means in how close a measured value is to the true value.
For example if true weight of a rat is 3.2 kg
Measured value 1 - 3.5 kg
measured value 2 - 3.1 kg
Then Measured value 2 is more accurate as it is more close to true value.

Precious means in how much depth a quantity is measured.
For example-
3.55 kg is more precise than 3.5 kg
eg2 - 0.1 mm is more precise than 1 mm.

Answer 2

Hello Dear !
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Q1. What are errors ?

A1. Every measurement by any measuring instrument or any other methods of measurement contains some uncertainty . This uncertainty in any measurement is said to be an error .

Q2. What are the types of errors ?

A2. Errors can be classified into three types :
i) Gross errors
ii) Measurement errors
iii) Blunders

Here, Measurement errors are of these types into :

i) Least count error : the smallest value that can be measured by measuring instrument without any uncertainty is called least count error.

ii) Absolute error : the magnitude of the difference between the individual measurement and the true value of the quantity is called absolute error of measurement.

iii) Mean Absolute error

iv) Relative Error : it is the ratio of the mean absolute error to the mean value of the quantative of measurement.

v) Percentage error : when relative error is measured in percentage then it is called percentage error .

[ Kindly , have a look at the attachment , it will help you to know the various classifications of errors ]

Q3. Differentiate b/w Accuracy and Precision .

A3. Accuracy :
It determines how close the measurement is to the true value of the quantity .
Ex - If weigh any object and it comes 10kg every time but it's actual weight is 15kg then it is said to be that your measurement isn't accurate .

Precision :
It is the resolution or limit of the measured quantity .
Ex - If you weigh any object for more than 3-4 times times and observe that the objects weights the same every time ( let the weight be 15kg) , then it means that your measurement is precised .

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Hope It Helps !