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M.C.Q (1 Marks)

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9 questions · self-marked practice — reveal the answer and mark yourself.

Question 11 Mark
The area of the region bounded by the circle $x^2+y^2$ $=9$ in the first quadrant is :
Answer
(C) Area bounded by circle in first quadrant
$
=\frac{1}{4} \pi a^2=\frac{1}{4} \pi \times(3)^2=\frac{9 \pi}{4}
$
Correct option is (C) $\frac{9 \pi}{4}$.
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Question 31 Mark
Area of circle $x^2+y^2=4$ :
Answer
(C) $4 \pi$
Circle $x^2+y^2=4$
$
\begin{aligned}
\therefore \quad(x)^2+(y)^2 & =(2)^2 \\
\text { Area of circle } & =\pi(\text { radius })^2=\pi(2)^2 \\
& =4 \pi
\end{aligned}
$
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Question 51 Mark
The area of the region bounded by the parabola $y=\sin ^2 x$, lines $x=\frac{\pi}{2}, x=\pi$ and $x$-axis is :
Answer

Image
Hence the correct option is (B).
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Question 71 Mark
The area bounded by the parabola $x^2=4 y$ and its latus rectum is:
Answer
(D)
$x^2=4 y$ and latus rectum $y=1$
The parabola is symmetrical about $y$-axis, hence required area $=2 \int_0^1 x d y$
Image
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Question 81 Mark
The whole area of the ellipse $\frac{x^2}{25}+\frac{y^2}{16}=1$ is :
Answer
Ellipse $\frac{x^2}{25}+\frac{y^2}{16} =1$
$\Rightarrow \frac{x^2}{(5)^2}+\frac{y^2}{(4)^2} =1$
Image
$\Rightarrow \frac{y^2}{(4)^2}=1-\frac{x^2}{(5)^2}=\frac{(5)^2-x^2}{(5)^2}$
$\Rightarrow y^2=\frac{(4)^2}{(5)^2}\left((5)^2-x^2\right)$
$\Rightarrow y=\frac{4}{5} \sqrt{(5)^2-x^2}$
$\text { Required area }= \text{ABCDA}$
$=4 \times \text { OABO }$
$\quad(\because \text { The ellipse is symmetrical about both the axes })$
$=4 \int_0^5 y d x$
$=4 \int_0^5 \frac{4}{5} \sqrt{(5)^2-x^2} d x$
$=\frac{16}{5}\left(\frac{1}{2} x \sqrt{(5)^2-x^2}+\frac{(5)^2}{2} \sin ^{-1}\left(\frac{x}{5}\right)\right)_0^5$
$=\frac{16}{5}\left(0+\frac{(5)^2}{2} \times \frac{\pi}{2}-0-0\right)$
$=4 \times 5 \pi$
$=20 \pi \text { square units. }$
Hence the correct option is $(D)$. 
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M.C.Q (1 Marks) - MATHS STD 12 Science Questions - Vidyadip