Answer:
Explanation:
Option A is the correct answer
The correct answer is option B. X-rays are the waves found in the electromagnetic spectrum at a wavelength of 1x10^-11 - 1x10^-8 m and frequencies of 3x10^16 to 3x10^19 Hz. These waves penetrate easily through certain materials which made them usefule in the field of medicine.
Answer: 226 Subscript 88 Baseline Upper R a right arrow Superscript 222 Subscript 86 Baseline Upper R n + Superscript 4 Subscript 2 Baseline Upper H e
Explanation:
Alpha decay : When a larger nuclei decays into smaller nuclei by releasing alpha particle. In this process, the mass number and atomic number is reduced by 4 and 2 units respectively.
The general representation of alpha decay reaction is:

Representation of Radium decays to form Radon

Thus 226 Subscript 88 Baseline Upper R a right arrow Superscript 222 Subscript 86 Baseline Upper R n + Superscript 4 Subscript 2 Baseline Upper H e represents alpha decay.
68000 = 6.8 * 10000 = 6.8 * 10^4
hope this helps? c;
My guess is that water is a liquid and not a solid, or a gas. It can be heated by us or by the suns rays, which if done by the suns rays the water azorbs the light rising the temp to the point of boil which then makes the water evaporate into the air, and thus making cloud in the sky that we see all the time thus when the clouds become big enough it begins to rain. ( also called the water cycle)