Is the eye more sensitive to intermittent light/flashlight?

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Is the eye more sensitive to intermittent light/flashlight than to constant light , if both have the same intensity ?

It doesn't say

jbriggs444
Homework Helper
It doesn't say
The first paragraph speaks of the purpose of the iris. What happens if you shine a light into someone's eye?

ZapperZ
Staff Emeritus
Is the eye more sensitive to intermittent light/flashlight than to constant light , if both have the same intensity ?

What exactly do you mean by "more sensitive"? Why do you think it should be more sensitive when the eye requires time to adjust its pupil during exposure of light? And how "intermittent" is this? If the time in between light flash is less than 0.02 seconds, you can no longer tell the difference between intermittent source and cw source (why do you think old-fashion film movies run at 24 frames per second?). I wouldn't call this "more sensitive" at all.

Zz.

What exactly do you mean by "more sensitive"? Why do you think it should be more sensitive when the eye requires time to adjust its pupil during exposure of light? And how "intermittent" is this? If the time in between light flash is less than 0.02 seconds, you can no longer tell the difference between intermittent source and cw source (why do you think old-fashion film movies run at 24 frames per second?). I wouldn't call this "more sensitive" at all.

Zz.
Logically if you flash a light into someone's eye, he blinks. Doesn't this mean that the eye is more sensitive to flash-light ?

ZapperZ
Staff Emeritus
Logically if you flash a light into someone's eye, he blinks. Doesn't this mean that the eye is more sensitive to flash-light ?

No, it means that the brain and reflex action are "sensitive" to the sudden appearance of bright light. This is a physiological question, not a physics question.

This is why are asked you to DEFINE what you mean by "sensitive". As someone who works in increasing sensitivity and resolution of light detectors, I define "sensitivity" as the quantum efficiency of that detector.

You are now in a science forum. You need to be aware that many of the terms being used often have clear, well-defined meanings in science/physics. So when you use something, unless you clearly state exactly what you are seeking, then either we interpret this the way it is used in science, or it will make for a very confusing discussion, like this one.

Zz.

jbriggs444
Homework Helper
Logically if you flash a light into someone's eye, he blinks. Doesn't this mean that the eye is more sensitive to flash-light ?
The effect I was fishing for was the fact that if you shine a light into a person's eyes, the pupils contract. But please do not let that distract you from answering @ZapperZ

This was all that was specified in the exam question. We got no further details or specifications.

ZapperZ
Staff Emeritus
This was all that was specified in the exam question. We got no further details or specifications.

This this is school-type question that should be done in the HW/Coursework forum, AND must be accompanied by (i) the full question and (ii) a show of what you attempted.

If this is an exam question that you should be doing on your own, but instead you sought help on here, then you are in deep doo doo.

Zz.

berkeman
Mentor
This was all that was specified in the exam question. We got no further details or specifications.