Mathematics

Problem

In an electronic experiment the resistance

R

(in kilo-ohms) of a certain sensor is modelled by the relation

R=\dfrac{1}{I}

, where the current

I

(in milliamperes) may be positive (forward direction) or negative (reverse direction). a. (i) Calculate

R

when

I=0.002\,\text{mA}

and when

I=-0.002\,\text{mA}

. Write each answer in scientific notation. b. (ii) Determine the magnitude of

R

when

|I|

decreases to

0.0001\,\text{mA}

. Show your working. c. (iii) Referring to limit ideas, describe what happens to the value of

R

I

approaches

0

from the positive side and from the negative side.