Join the Most Relevant JEE Main 2025 Test Series & get 99+ percentile! Join Now
Search any question & find its solution
Question: Answered & Verified by Expert
Let $(3,4,-1)$ and $(-1,2,3)$ be the end points of a diameter of a sphere. Then, the radius of the sphere is equal to
MathematicsHeights and DistancesCOMEDKCOMEDK 2017
Options:
  • A 2 units
  • B 3 units
  • C 6 units
  • D 7 units
Solution:
1374 Upvotes Verified Answer
The correct answer is: 3 units
Let $P(3,4,-1)$ and $Q(-1,2,3)$ be the end points of the diameter of a sphere.
$\therefore$ Length of diameter $=P Q$
$\begin{aligned}
&=\sqrt{(-1-3)^{2}+(2-4)^{2}+(3+1)^{2}} \\
&=\sqrt{16+4+16}=\sqrt{36}=6 \text { units } \\
\therefore \quad \text { Radius } &=\frac{6}{2}=3 \text { units }
\end{aligned}$

Looking for more such questions to practice?

Download the MARKS App - The ultimate prep app for IIT JEE & NEET with chapter-wise PYQs, revision notes, formula sheets, custom tests & much more.