Honeybees accumulate charge as they fly, and they transfer charge to the flowers they visit. Honeybees are able to sense electric fields; tests show that they can detect a change in field as small as 0.77 N/C. Honeybees seem to use this sense to determine the charges on flowers in order to detect whether or not a flower has been recently visited, so they can plan their foraging accordingly. As a check on this idea, let's do a quick calculation using typical numbers for charges on flowers. If a bee is at a distance of 24 cm, can it detect the difference between flowers that have a +30 pC charge and a +40 pC charge?

difference between the field  = 1.56 N/C

as; 1.56 N/C is greater than 0.77 N/C;

Hence, Honeybees can detected the difference

Explanation:

Given the data in the question;

distance r = 24 cm = 0.24 m

charge 1 Q1 = +30 pC = 30×10⁻¹² C

charge 2 Q2 = +40 pC = 40×10⁻¹² C

Now, electric field due to +30 pC charge

E1 = kQ1/r²

where coulomb constant k is 9 × 10⁹ N.m²/C²

so we substitute

E1 = [( 9 × 10⁹ ) × (30×10⁻¹²)] / (0.24)²

E1 = 0.27 / 0.0576

E1 = 4.69 N/C

electric field due to +40 pC charge

E2 = kQ1/r²

E2 = [( 9 × 10⁹ ) × (40×10⁻¹²)] / (0.24)²

E2 = [( 9 × 10⁹ ) × (40×10⁻¹²)] / (0.24)²

E2 = 0.36 / 0.0576

E2 = 6.25 N/C

Now,

E2 = E1 =  6.25 N/C - 4.69 N/C = 1.56 N/C

difference between the field  = 1.56 N/C

as; 1.56 N/C is greater than 0.77 N/C;

Hence, Honeybees can detected the difference