Question

Which statement about the light microscope is correct?
A As the smallest distance to see two points as distinct separate points decreases, the
resolution also decreases.
B If the resolution is 220 nm, then a bacterium 0.2 μm in diameter will not be visible.
C If the wavelength of light is 600 nm, then two membranes 300 nm apart will be visible as two
distinct membranes.
D Using visible light of a longer wavelength, such as red light, will improve the resolution.

Answer 1

Im not sure about the answer but I can help you by eliminating few options
Option A is wrong because as distance increases, the resolution decreases. They are inversely proportional.
Option D is wrong as Distance is based on three parameters out of which wavelength is one. Decreasing the value of wavlength will decreases the value of distance giving you a better resolution.
Im not sure about B and C but for additonal information a light microscope can resolve details upto 0.2um
there you go (:

Answer 2

As I see it, both B and C seem correct. The bacterium will be 200nm so it will not be visible with a resolution of 220nm.
As for C, it also seems right as the limit of resolution is half the wavelength of the radiation. O.o