Question
1.
2.
3.
4.
Answer (Detailed Solution Below)
Option 4 : 1/4 / 1/4
Advertisement
Detailed Solution
सही उत्तर 1/4 / 1/4 है।
Key Points
Helpful?
prepsnap.in • Part -AQuestion:
According to the $\cos^4$ law, illumination at a point 45 degrees off the lens axis falls to what fraction of the centre value? / $\cos^4$ नियम के अनुसार, लेंस अक्ष से 45 डिग्री दूर किसी बिंदु पर प्रकाश केंद्र मान के कितने भाग तक गिरता है?
1.
1/2 / 1/2
2.
$1/\sqrt{2}$ / $1/\sqrt{2}$
3.
3/4 / 3/4
4.
1/4 / 1/4
Correct Answer: 1/4 / 1/4
Falloff equals $\cos^4\theta$; at $45^\circ$, $\cos 45^\circ = \sqrt{2}/2$, and $(\sqrt{2}/2)^4 = 1/4$, so edges receive one-quarter of the central illumination (two stops down).
Downloaded from PrepSnap (prepsnap.in)