Question

Consider the figure given below

In the above figure, it is shown that three planes are intersecting at a point $O$, such that these three planes are mutually perpendicular to each other.
The distances measured from $X Y$-plane upwards in the direction of $O Z$ are taken as ...A ... and those measured downwards in the direction of $O Z^{\prime}$ are taken as ...B.... Similarly, the distance measured to the right of $Z X$-plane along $O Y$ are taken as ...C... to the left of $Z X$-plane and along $O Y^{\prime}$ as ...D..., in front of the $Y Z$-plane along $O X$ as ...E... and to the back of it along $O X^{\prime}$ as ...F... . In the above passage, $A , B , C , D , E$ and $F$ refer to

• A. $A , B , C \rightarrow$ negative and $D , E , F \rightarrow$ positive
• B. A, B, C $\rightarrow$ positive and $D, E, F \rightarrow$ negative
• C. A, E, C $\rightarrow$ positive and $B, D, F \rightarrow$ negative
• D. $A, C, E \rightarrow$ negative and $B, D, F \rightarrow$ positive

Answer 1

Answer: (C)

These problems are based on coordinate axes and coordinate planes in three dimensional space.

The distances measured from $X Y$-plane upwards in the direction of $O Z$ are taken as positive and those measured downwards in the direction of $O Z^{\prime}$ are taken as negative. Similarly, the distance measured to the right of ZX-plane and along OY are taken as positive, to the left of ZX-plane and along $O Y^{\prime}$ as negative, in front of the $Y Z$-plane along $O X$ as positive and to the back of it along $O X^{\prime}$ as negative.