Question

Direction ratios of x-axis are:

• A. (0,1,0)
• B. (1,0,0)
• C. (0,0,1)
• D. (1,1,1)

Hint:

To remember: The "1" always stays in the position of the axis named. X-axis is (1,0,0), Y-axis is (0,1,0), and Z-axis is (0,0,1).

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Direction ratios of a line are any three numbers which are proportional to the direction cosines of the line. For the axes, these represent the unit vector components along that specific axis.
Step 2: Detailed Explanation:
The x-axis makes an angle of 0° with itself, 90° with the y-axis, and 90° with the z-axis. The direction cosines ($l, m, n$) are: $l = \cos(0^\circ) = 1$ $m = \cos(90^\circ) = 0$ $n = \cos(90^\circ) = 0$ Any numbers proportional to $(1, 0, 0)$ are direction ratios. The simplest form is $(1, 0, 0)$.
Step 3: Final Answer:
The correct option is (b).