Find the minimum thickness (in nm) of a soap bubble that appears red when illuminated by white light perpendicular to its surface. Take the wavelength to be 680 nm, and assume the same index of refraction as water.

The thickness of the soap bubble is 170 nm.

Explanation:

Given that,

Wavelength of light,

We need to find the minimum thickness of a soap bubble that appears red when illuminated by white light perpendicular to its surface. Let t is the minimum thickness of the film. When reflection is taking place at an interface, then the condition for constructive interference is given by :

So, the thickness of the soap bubble is 170 nm.

emily ruth's annual premium is $1058.50

step-by-step explanation:

emily ruth is a female of 27 years age purchasing 20 year endowment insurance with face value $25000.

from the given table,

for females, the age of a male 3 years younger should be used.

so, we have to check for 24 year male for 20 year endowment.

it is 42.34 for every $1000 face value.

for a face value of $25000,

it is 25 * 42.34 = $1058.50

∴ emily ruth's annual premium is $1058.50