Physics And Measurement Question 176
Question: The relative density of material of a body is found by weighing it first in air and then in water. If the weight in air is (5.00 $ \pm 0.05 $ ) Newton and weight in water is (4.00 $ \pm $ 0.05) Newton. Then the relative density along with the maximum permissible percentage error is
Options:
A) 5.0 $ \pm $ 11%
B) 5.0 $ \pm $ 1%
C) 5.0 $ \pm $ 6%
D) 1.25 $ \pm $ 5%
Show Answer
Answer:
Correct Answer: A
Solution:
Weight in air $ =(5.00\pm 0.05)N $
Weight in water $ =(4.00\pm 0.05)N $
Loss of weight in water $ =(1.00\pm 0.1)N $
Now relative density $ =\frac{weightin\text{air }}{\text{weight }\text{loss in water}} $
i.e. R . D $ =\frac{5.00\pm 0.05}{1.00\pm 0.1} $
Now relative density with max permissible error $ =\frac{5.00}{1.00}\pm ( \frac{0.05}{5.00}+\frac{0.1}{1.00} )\times 100 $
$ =5.0\pm (1+10)% $
$ =5.0\pm 11% $
