SAT Mathematics Practice Test 2

Questions 42 and 43 refer to the followinginformation.

I=P/{4πr^2}

At a large distance r from a radio antenna, the intensity of the radio signal I is related to the power of the signal P by the formula above.

Question : 42 of 58

Marks: +1, -0

Which of the following expresses the square of the distance from the radio antenna in terms of the intensity of the radio signal and the power of the signal?

$r^2={IP}/{4π}$
$r^2=P/{4nI}$
$r^2={4nL}/P$
$r^2=I/{4πP}$

Validate

Solution:

To rearrange the formula

I=P/{4πr^2}

in terms of

r^2

,first multiply each side of the equation by

r^2

.This yields

r^2I=P/{4π}

Then dividing each side of

r^2I=P/{4π}

by I gives

r^2=P/{4πI}

Choices A, C, and D are incorrect and may result from algebraic errors during the rearrangement of the formula.

Go to Question:

Prev Question

Next Question