Radioactive sources have many uses.
The Table shows three uses of radioactive sources.
Table
| Use | Type of radiation used |
|---|---|
| household smoke alarm | |
| sterilising surgical instruments | |
| checking the thickness of paper in a factory |
Complete the Table by writing alpha, beta or gamma for each use.
Give one other use of radioactive sources.
Some food is irradiated with gamma rays before it is sold.
State why food is irradiated.