Mass number = no. of protons + no. of neutrons
so, it would be, 3+4 = 7
The mass of a radioactive element at time t is given by
where
is the mass at time zero, while
is the half-life of the element.
In our problem,
, t=121.0 s and
, so we can find the initial mass
:
Answer:
Laws are statements about something that's been observed and stated while a theory is an explanation of what's been observed. This connection between them forms a main idea that many people regulate as "what's normal."
Explanation:
Answer:
A lens
Explanation:
A lens forms images when light passes Through it bending the rays of in the process.A phenomena called refraction and the speed of light changes in the process because it enters a medium since it's wavelength is reduced.
