Question

5. Two samples have transmittance readings of 1% and 10%. The O.D. of the 10% reading will be than the O.D. of the 1% reading. A. 10 fold lower B. 10 fold higher C. 5 fold lower D. 5 fold higher E. 2 fold higher F. 2 fold lower

What is the answer? Explain why other choices are incorrect?

Answer 1

5. Correct answer is F. 2 fold lower

Because OD = 2 - log(%T)

So OD_10%/OD_1%= (2 - log10) / (2 - log1) = (2-1) / (2-0) = 1/2

So, if OD of 10% is X then OD of 1% will be 2X.

Hence, the answer is the O.D. of the 10% reading will be 2 fold lower than the O.D. of the 1% reading.

6. Correct answer is B. decrease

Because depth of field is inversely proportional to the magnification i.e. when magnification increases the depth of field decreases.

As depth of field measures the thickness of the subject and by increasing the magnification we can see a much lesser area of the subject.