Question

Figure shows a glowing mercury tube. The intensities at point A, B and C are related as
(a) B > C > A
(b) A > C > B
(c) B = C > A (d) B = C < A
Figure

Answer 1

Attached Figure shows a glowing mercury tube. The intensities at point A, B and C are related as (d) B = C < A

Explanation:

Since B and C are of the same size and are inclined to make the same vertical angle (If two lines cross each other the angles oppose one another. They always are equal. In this illustration the vertical angles are a ° and b °) with the source, they are going to have the same strength. But since A is closer with the source and forms an angle of $0^{0}$, A will have strength greater than C or B.  

Therefore the correct answer is Option (d) B = C < A .

Answer 2

Answer: The intensities at point A, B and C are related as (d) B = C < A

Explanation:

The intensity at B and C are equal since they are equidistant from the main source. A is at the source so will have greater intensity. Hence B=C< A

Mercury vapour lamps are very energy efficient when compared to any other incandescent and other fluorescent lights.