Question

Sharks and related fish can sense the extremely weak electric fields emitted by their prey in the surrounding waters. These detectors, located in their noses and called ampullae, are so sensitive they can detect a voltage gradient of 1 ?V across1 cm of seawater.How far apart would you have to place the poles of a 1.5 V battery to achieve the same electric field? (Choose one)1) 6.7×10-9 m2) 1.5×10-2 m3) 1.5×10-6 m4) 1.5×104 m

Answer 1

Answer

2) 1.5×10-2 m

Explanation

The potential difference is related to the electric field by:

$\Delta V=Ed$ (1)

where

$\Delta V$ is the potential difference

E is the electric field

d is the distance

We want to know the distance the detectors have to be placed in order to achieve an electric field of

$E=1 V/cm=100 V/m$

when connected to a battery with potential difference

$\Delta V=1.5 V$

Solving the equation (1) for d, we find

$d=\frac{\Delta V}{E}=\frac{1.5 V}{100 V/m}=0.015 m=1.5 \cdot 10^{-2} m$