This was because the experiment showed that a substance could emit radiation even while it was not exposed to light.
Well a question to ask would be if the mass of the material has changed significantly as that would determine that the substance is radioactive or if there have been any high readings found by a Geiger meter in certain period of time
hope that helps
Answer:
D.) They often form hydroxide ions.
Explanation:
They generate hydroxide ions in water. they are soapy to touch and bitter in taste. they conduct electricity.
(all bases have hydroxide ions)
6.4 times 10^-7 is the answer because you are moving your decimal places to the left so it will be negative 7
Answer:
photons
Explanation:
Where,
n is the number of photons
h is Plank's constant having value
c is the speed of light having value
is the wavelength of the light
Given that, wavelength = 514 nm = 
Energy = 10.0 mJ = 0.01 J ( 1 mJ = 0.001 J )
Applying the values as:-

photons