Cuando un pastel se deja a la intemperie por muchos días, este se descompone generando otras sustancias. El cambio que sufre el pastel se conoce con el nombre de:
Seleccione una:
a. Cambio reversible.
b. cambio natural.
c. Reacción química.
d. Cambio físico.

Cobalt-60 is an artificial radioisotope that is produced in a nuclear reactor and is used as a gamma-ray source in the treatment of certain types of cancer. if the wavelength of the gamma radiation from a cobalt-60 source is 1.00 × 10-3 nm, calculate the energy of a photon of this radiation.

If a plot weight (in g) vs. volume (in ml) for a metal gave the equation y= 13.41x and r^2=0.9981 what is the density of the metal?

Can someone me with 1 to 4 plz. fast