A radioactive element has a half life of 4 days. The fraction that has decayed in 16 days is?

caesium has a work function of 3 x 10-19J. the maximum energy of liberated electrons when it is illuminated by light of frequency 6.7 x 1014

HZ is?



[h = 6.6 x 1010-34Js]

Cancerous cells can be destroyed by?

If the decay constant of a radioactive substance is 0.231s-\(^1\), the half-life is?

A piece of radioactive material contains 10\(^{20}\) atoms.
If the half life of the material is 20 seconds, the number of disintegration in the first second is?