MCQ 11 Mark
Assertion (A) 8 persons can stay in a cubical room. Each person required $64 m^3$ of air. The side of cube is 8 m .
Reason (R) The surface area of cube can be represented as $6 s^2$, since a cube has six side and surface area of each side is represented by its length.
Reason (R) The surface area of cube can be represented as $6 s^2$, since a cube has six side and surface area of each side is represented by its length.
- ABoth A and R are true and R is correct explanation of A.
- ✓Both A and R are true but R is not correct explanation of A.
- CA is true but R is false.
- DA is false but R is true.
Answer
View full question & answer→Correct option: B.
Both A and R are true but R is not correct explanation of A.
(B) Both A and R are true but R is not correct explanation of A.
Volume required by each person $=64 m^3$
Volume required by 8 person $=8 \times 64=512 m^3$
which is the total volume of room.
Let $a$ be the side of room.
$
\begin{aligned}
\therefore & & a^3 & =512 \\
\Rightarrow & & a^3 & =8^3 \\
\Rightarrow & & a & =8
\end{aligned}
$
$\therefore$ Side of cube is 8 m , which is correct. But Reason (R) is not correct explanation of Assertion (A).
Volume required by each person $=64 m^3$
Volume required by 8 person $=8 \times 64=512 m^3$
which is the total volume of room.
Let $a$ be the side of room.
$
\begin{aligned}
\therefore & & a^3 & =512 \\
\Rightarrow & & a^3 & =8^3 \\
\Rightarrow & & a & =8
\end{aligned}
$
$\therefore$ Side of cube is 8 m , which is correct. But Reason (R) is not correct explanation of Assertion (A).