Inverse square law test questions - Higher Physics Revision

1

How is the irradiance of electromagnetic radiation defined?

The energy per second of the radiation per unit area

The total energy of radiation for each square metre

The area affected by the radiation divided by the power of the radiation

2

Which graph illustrates the relationship between irradiance from a point source and distance from the source?

Graph of irradiance against distance. Line emanating from origin extends upwards at 45 degree angle.

Graph of irradiance against distance. Line starts at top of y-axis origin and curves anti-clockwise towards furthest point of x-axis origin.

Graph of irradiance against one over distance squared. Line starts at origin and extends up at 45 degree angle.

3

The irradiance from a small lamp is 0.584 W m^-2 at a distance 0.64 m from the lamp. What would be the expected irradiance at a distance 0.96 m from the lamp?

0.260 W m^-2

0.389 W m^-2

1.31 W m^-2