Chapter 16, Problem 63A

To determine

The effect on the luminous intensity of a lamp as it is moved farther away from the book.

Answer to Problem 63A

No change

Explanation of Solution

Introduction:

The illuminance of a source at a distance $r$ is given by,

  $E=\frac{P}{4\pi r^2}$

Where $P=\text{luminous flux of the source}$

The luminous intensity is the property of the source and does not change if the source is moved away from the object.

Conclusion:

Hence, the luminous intensity of the lamp will remain same if it moves away from the book.