Question

Calculate the charge on an alpha particle. Given charge on a proton $ = 1.6 \times {10^{ - 19}}C $ .

Answer 1

Hint : To solve this question, we need to obtain the atomic number of the Helium atom with the help of the periodic table. The atomic number means nothing but the number of protons in the nucleus of that atom. Then we can get the final answer, after using the value of the charge on a proton given in the question.

Complete step by step answer
We know that an alpha particle is similar to the nucleus of the Helium atom. The only difference is that it has no electrons. So the charge on the alpha particle is equal to the charge on the Helium nucleus. In the modern periodic table, the Helium is present at the second position. This means that the atomic number of a helium atom is equal to $ 2 $ . We know that the atomic number of an element indicates the number of protons on the nucleus of that element. So this means that the number of protons in the helium nucleus is equal to $ 2 $ .
According to the question, the charge on a proton is $ e = 1.6 \times {10^{ - 19}}C $ . So the charge of the helium nucleus becomes
 $\Rightarrow q = 2e $
 $ \Rightarrow q = 2 \times 1.6 \times {10^{ - 19}}C $
On solving we get
 $\Rightarrow q = 3.2 \times {10^{ - 19}}C $
As shown above, the charge on an alpha particle is equal to the charge on the helium nucleus. So the charge on an alpha particle is given by
 $\Rightarrow {q_\alpha } = 3.2 \times {10^{ - 19}}C $
Hence, the charge on an alpha particle is equal to $ 3.2 \times {10^{ - 19}}C $ .

Note
The alpha particles discussed in this question are used in many day to day applications. They are used in smoke detectors, which is used as a fire indicator. Also, they are used in the treatment of some types of cancer.