The count rate from a radioactive source emitting -radiation is inversely proportional to the square of the

The count rate from a radioactive source emitting γ-radiation is inversely proportional to the square of the distance from the source. Sources emitting γ- radiation also emit α- and β-radiation and are roughly spherical with a diameter of 2 cm.

a. What are the dependent and independent variables?

b. Suggest a quantity to be controlled.

c. How could you make sure that only γ-radiation is detected?

d. How would you measure the count rate? Draw a diagram of the apparatus and explain how it is used.

e. How would you make the uncertainty in the count rate as small as possible?

f. Suggest one difficulty in measuring the distance and how this difficulty may be reduced.

g. Suggest a safety precaution.