Physics

1The threshold frequency is the

2An alpha particle is the same as a

3In beta-minus decay, the atomic number of the nucleus

4When ²³⁸₉₂U emits an alpha particle, the new nucleus has mass number

5A nucleus emits one alpha and two beta particles. Its atomic number

6The emission of electrons from a metal surface when light falls on it is the

7²²⁶₈₈Ra decays by α emission. The daughter nucleus is

8A sample has a half-life of 5 days. What fraction remains after 20 days?

9A radioactive count falls from 640 to 40 counts/min in 20 minutes. The half-life is

10The de Broglie wavelength of a particle increases when its