| X | Y | |
|---|---|---|
| Protons | 6 | 6 |
| Neutrons | 6 | 6 |
Mass number of X = Number of protons + Number of neutrons = 6 + 6 = 12
Mass number of Y = Number of protons + Number of neutrons = 6 + 8 = 14
These two atomic species X and Y have the same atomic number, but different mass numbers. Hence, they are isotopes.
Length (in hours) | Number of lamps |
|---|---|
300 − 400 | 14 |
400 − 500 | 56 |
500 − 600 | 60 |
600 − 700 | 86 |
700 − 800 | 74 |
800 − 900 | 62 |
900 − 1000 | 48 |
(i) Represent the given information with the help of a histogram.
(ii) How many lamps have a lifetime of more than 700 hours?
Why was Santosh sent to the local school?