 # NCERT Exemplar Solutions Class 7 Science Solutions for Transportation in Animals and Plants - Exercise in Chapter 11 - Transportation in Animals and Plants

Question 18 Transportation in Animals and Plants - Exercise

Observe Figure 11.2 and answer the given questions: (a) Name the instrument.

(b) Label the parts A, B and C.

a) The given instrument is stethoscope

b) Video transcript
"hello everyone welcome to later this is priya and here we have a question about calculating the percentages of different isotopes so let us read the question the average atomic mass of a sample of an atom element is 16.2 mu what are the percentages of isotopes 8x16 and 8x18 in the sample so what we know is so when we do the average of these two at uh elements we'll get a percentage of 100 so let percentage let percentage of atomic element with atomic mass 16 be a so we are just taking the first element first isotope as a and that of the next isotope x with 6 18 mass b 100 minus a as per given data we know the average of these two will be 16.2 nu so equal to so as we know the formula of uh finding the average atomic mass so it is 16 a by 100 plus 18 100 minus a by 100 so if we simplify this we'll get 16 a plus 1800 minus 18 a by 100 so if these hundred comes to the rhs it will be 1620 equal to 1800 minus this and this will subtract will get 2 8 okay i'm grabbing a little bit so the next step is to simplify this one so 2 a equal to if we subtract this and this 1800 minus 16 120 will get 90 per 90. we will subtract this 1800 minus 16 20 will get 0 8 180 so we get 180 and that implies a equal to 180 by 2 it is 90 so the first percentage of this isotope is 90 and the remaining percentage so if from the now from the 900 if we subtract the 90 we will have 10 10 so the second element has the percentage of 10 first element has percentage of 90 so this is about the question hope you understand this video if you like my video please subscribe to our little channel and if you have any doubts you can keep a message in comment box thank you"
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