Question

The line $\frac{x-x_1}{0}=\frac{y-y_1}{1}=\frac{z-z_1}{2}$ is:

• A. parallel to x-axis
• B. perpendicular to x-axis
• C. perpendicular to YOZ plane
• D. parallel to y-axis

Answer 1

Answer: (B)

perpendicular to x-axis

$L=\frac{x-x_1}{0}=\frac{y-y_1}{1}=\frac{z-z_1}{2}$

dr's of line $L=(0,1,2)=d_1$

dr's of x-axis =$(1,0,0)=d_2$

clearly the line is not parallel to x-axis,if it was parallel then dr's would have been same.

$\overline{d_1}\cdot \overline{d_2}=3(i+2\hat{k})\cdot \left(\hat{i}\right)$

$=0$

So, the line $L_1$ is perpendicular to x.