Question

What is the contrast ratio of real world image to the CRT display image?

(a) 1:1

(b) 4:1

(c) 7:3

(d) 2:1

Answer 1

The correct answer is (c) 7:3

The best explanation: A combiner allows 70% of the outside world light and 30% of the CRT produced collimated light to pass through it. Thus contrast ration= brightness of real-world light : brightness of CRT light = 70 : 30 = 7 : 3 .