Exercise XV — task. Science CBSE, Class 9.

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State whether true or false. If false, correct the statement:

a. The mass of an electron is about $\frac{1}{2000}$ times that of proton.

An electron has a mass of nearly $\frac{1}{2000}$ times that of a proton.
A proton's mass is roughly $\frac{1}{2800}$ times that of an electron.

b. An isotope of iodine is used for making tincture iodine, which is used as a medicine.

Making tincture iodine, which is used as a medicine, requires an isotope of iodine.
An isotope of iodine is used as a tracer to determine the manner and rate of iodine intake by the thyroid gland in our body.

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