Qus : 1
NIMCET PYQ
1
If the circles
$ x^2 + y^2 + 2x + 2ky + 6 = 0$
and
$x^2 + y^2 + 2ky + k = 0$
intersect orthogonally, then $k$ is:
1
$2 \text{ or } -\dfrac{3}{2}$ 2
$-2 \text{ or } -\dfrac{3}{2}$ 3
$2 \text{ or } \dfrac{3}{2}$ 4
$-2 \text{ or } \dfrac{3}{2}$ Go to Discussion
NIMCET Previous Year PYQ
NIMCET NIMCET 2012 PYQ
Solution
Two circles:
$C_1:\; x^2 + y^2 + 2x + 2ky + 6 = 0$
$C_2:\; x^2 + y^2 + 2ky + k = 0$
Orthogonality condition for circles
$x^2 + y^2 + 2g_1 x + 2f_1 y + c_1 = 0$
and
$x^2 + y^2 + 2g_2 x + 2f_2 y + c_2 = 0$
is:
$2(g_1g_2 + f_1f_2) = c_1 + c_2$
From $C_1$:
$g_1 = 1,\; f_1 = k,\; c_1 = 6$
From $C_2$:
$g_2 = 0,\; f_2 = k,\; c_2 = k$
Apply formula:
$2(1\cdot 0 + k\cdot k) = 6 + k$
$2k^2 = 6 + k$
$2k^2 - k - 6 = 0$
$(2k + 3)(k - 2) = 0$
So:
$k = 2 \;\text{or}\; -\dfrac{3}{2}$
Qus : 2
NIMCET PYQ
4
Number of distinct solutions of
$ x^{2} = y^{2} $
and
$ (x - a)^{2} + y^{2} = 1 $
where $a$ is any real number:
1
$0,1,2,3,4$ 2
$0,1,3$ 3
$0,1,2$ 4
$0,2,3,4$ Go to Discussion
NIMCET Previous Year PYQ
NIMCET NIMCET 2011 PYQ
Solution $ x^{2} = y^{2} \Rightarrow x = \pm y $
Intersection with a circle shifted by $a$ gives variable counts depending on $a$.
Possible solution counts: $0,1,2,4$
Qus : 11
NIMCET PYQ
4
The circle $x^2 + y^2 = 9$ is contained in the circle $x^2 + y^2 - 6x - 8y + 25 = c^2$ if
1
$c = 2$ 2
$c = 3$ 3
$c = 5$ 4
$c = 10$ Go to Discussion
NIMCET Previous Year PYQ
NIMCET NIMCET 2010 PYQ
Solution Given circle 1: center (0,0), radius 3
Circle 2 (rewrite): (x-3)² + (y-4)² = c²
Distance between centers = √(3² + 4²) = 5
Condition: larger radius ≥ smaller radius + distance
c ≥ 3 + 5 = 8
Given options → smallest suitable c is 10
Qus : 12
NIMCET PYQ
3
The circles whose equations are $x^2+y^2+c^2=2ax$ and $x^2+y^2+x^2-2by=0$ will touch one another externally, if
1
$\dfrac{1}{b^2}+\dfrac{1}{c^2}=\dfrac{1}{a^2}$
2
$\dfrac{1}{c^2}+\dfrac{1}{a^2}=\dfrac{1}{b^2}$
3
$\dfrac{1}{a^2}+\dfrac{1}{b^2}=\dfrac{1}{c^2}$
4
None of these Go to Discussion
NIMCET Previous Year PYQ
NIMCET NIMCET 2018 PYQ
Solution
Qus : 13
NIMCET PYQ
3
Segments of the lines $2x+3y=1$ and $4x-3y=11$ are diameters of a circle of area $153.94$ square units. Then, the equation of this circle with integer radius is:
1
$x^2+y^2+4x-2y-44=0$ 2
$x^2+y^2+4x-2y+44=0$ 3
$x^2+y^2-4x+2y-44=0$ 4
$x^2+y^2-4x+2y+44=0$ Go to Discussion
NIMCET Previous Year PYQ
NIMCET NIMCET 2026 PYQ
Solution Since the given lines are diameters of the circle, both lines pass through the centre of the circle.
So, the centre is the intersection point of
$2x+3y=1$ .....$(1)$
$4x-3y=11$ .....$(2)$
Adding $(1)$ and $(2)$,
$6x=12$
$x=2$
Put $x=2$ in $(1)$:
$2(2)+3y=1$
$4+3y=1$
$3y=-3$
$y=-1$
So, centre of the circle is
$(2,-1)$
Now, area of circle is
$\pi r^2=153.94$
Since $153.94\approx 49\pi$,
$r^2=49$
$r=7$
Equation of circle is
$(x-2)^2+(y+1)^2=7^2$
$(x-2)^2+(y+1)^2=49$
Expanding,
$x^2-4x+4+y^2+2y+1=49$
$x^2+y^2-4x+2y-44=0$
Qus : 14
NIMCET PYQ
4
A circle with its center in the first quadrant touches both the coordinate axes and the line
x-y-2=0. Then the area of the circle is
1
$\dfrac{\pi}{2}$ 2
$4 \pi$ 3
$\pi$ 4
$2\pi$ Go to Discussion
NIMCET Previous Year PYQ
NIMCET NIMCET 2025 PYQ
Solution A circle touching both coordinate axes has center $(r, r)$ and radius $r$.
It also touches the line $x - y - 2 = 0$.
So the distance from $(r, r)$ to the line equals $r$:
$\dfrac{|r - r - 2|}{\sqrt{1^{2} + (-1)^{2}}} = r$
$\dfrac{2}{\sqrt{2}} = r$
$r = \sqrt{2}$
Area of the circle:
$\pi r^{2} = \pi(\sqrt{2})^{2} = 2\pi$
Qus : 15
NIMCET PYQ
3
The circle $x^2 + y^2+ \alpha x+ \beta y+ \gamma=0$ is the image of the circle $x^2 + y^2- 6x- 10y+ 30=0$ across
the line 3x + y = 2. The value of $[\alpha+ \beta+ \gamma]$ is (where [.] represents the floor function.)
1
20 2
22 3
23 4
21 Go to Discussion
NIMCET Previous Year PYQ
NIMCET NIMCET 2025 PYQ
Solution Given circle:
$x^{2}+y^{2}-6x-10y+30=0$
Center and radius:
$C(3,5), \quad r=2$
We reflect $C(3,5)$ across the line
$3x + y - 2 = 0$.
Compute reflection factor:
$k = \dfrac{2(3\cdot 3 + 5 - 2)}{3^{2} + 1^{2}}
= \dfrac{24}{10}
= \dfrac{12}{5}$
Reflected center:
$x' = 3 - 3k = 3 - \dfrac{36}{5} = -\dfrac{21}{5}$
$y' = 5 - k = 5 - \dfrac{12}{5} = \dfrac{13}{5}$
So new center is:
$C'\left(-\dfrac{21}{5},\dfrac{13}{5}\right)$
The image circle is
$x^{2}+y^{2}+\alpha x+\beta y+\gamma = 0$
Using center formula:
$-\dfrac{\alpha}{2} = -\dfrac{21}{5} \Rightarrow \alpha = \dfrac{42}{5}$
$-\dfrac{\beta}{2} = \dfrac{13}{5} \Rightarrow \beta = -\dfrac{26}{5}$
Using radius $r=2$:
$\left(-\dfrac{21}{5}\right)^{2} + \left(\dfrac{13}{5}\right)^{2} - \gamma = 4$
$\dfrac{610}{25} - \gamma = 4$
$\gamma = \dfrac{102}{5}$
Now compute:
$\alpha + \beta + \gamma
= \dfrac{42}{5} - \dfrac{26}{5} + \dfrac{102}{5}
= \dfrac{118}{5}
= 23.6$
Thus,
$\boxed{23}$
Qus : 16
NIMCET PYQ
2
A line passing through (4, 2) meets the x and y-axis at P and Q respectively. If O is the origin, then the locus of the centre of the circumcircle of ΔOPQ is -
1
$\dfrac{1}{x}+\dfrac{1}{y}=2$ 2
$\dfrac{2}{x}+\dfrac{1}{y}=1$ 3
$\dfrac{1}{x}+\dfrac{2}{y}=2$ 4
$\dfrac{1}{x}+\dfrac{1}{y}=\dfrac{1}{2}$ Go to Discussion
NIMCET Previous Year PYQ
NIMCET NIMCET 2018 PYQ
Solution
Qus : 20
NIMCET PYQ
3
There are n equally spaced points 1,2,...,n marked on the circumference of a circle. If the point 15 is directly opposite to the point 49, then the total number of points is
1
50 2
68 3
66 4
70 Go to Discussion
NIMCET Previous Year PYQ
NIMCET NIMCET 2016 PYQ
Solution Given: $n$ equally spaced points $1, 2, \ldots, n$ marked on circumference of a circle
Point $15$ is directly opposite to point $49$
Since the points are equally spaced on a circle, two points are directly opposite if they are diametrically opposite
$\therefore$ The number of points between $15$ and $49$ on each semicircle must be equal
Points between $15$ and $49$ (going from $15$ to $49$):
$16, 17, 18, \ldots, 48$
Number of points $= 48 - 16 + 1 = 33$
Since both semicircles must have equal number of points between the opposite points:
Points on other semicircle (from $49$ to $15$) must also be $33$
$\therefore$ Total number of points $= 2 + 33 + 33 = 68$
Qus : 22
NIMCET PYQ
2
. Two common tangents to the circles $x^2 + y^2 = 2a^2$ and parabola $y^2 = 8ax$ are
1
$x = \pm (y + 2a)$ 2
$y = \pm (x + 2a)$ 3
$x = \pm (y + a)$
4
$y = \pm (x + a)$ Go to Discussion
NIMCET Previous Year PYQ
NIMCET NIMCET 2016 PYQ
Solution Given circle: $x^2 + y^2 = 2a^2$
Given parabola: $y^2 = 8ax$
**Equation of tangent to parabola:**
For parabola $y^2 = 8ax$, tangent is:
$y = mx + \dfrac{2a}{m}$ ...(i)
**Condition for tangent to circle:**
For line $y = mx + \dfrac{2a}{m}$ to be tangent to circle $x^2 + y^2 = 2a^2$,
distance from centre $(0,0)$ = radius $= \sqrt{2}\ a$
$\Rightarrow \dfrac{\left|\dfrac{2a}{m}\right|}{\sqrt{1 + m^2}} = \sqrt{2}\ a$
$\Rightarrow \dfrac{2a}{|m|\sqrt{1+m^2}} = \sqrt{2}\ a$
$\Rightarrow \dfrac{2}{|m|\sqrt{1+m^2}} = \sqrt{2}$
$\Rightarrow |m|\sqrt{1+m^2} = \sqrt{2}$
Squaring both sides:
$\Rightarrow m^2(1+m^2) = 2$
$\Rightarrow m^4 + m^2 - 2 = 0$
$\Rightarrow (m^2 + 2)(m^2 - 1) = 0$
$\Rightarrow m^2 = 1 \quad (\because m^2 = -2 \text{ is not possible})$
$\Rightarrow m = \pm 1$
**Substituting in (i):**
When $m = 1$: $y = x + 2a$
When $m = -1$: $y = -x - 2a$
$\therefore$ The two common tangents are:
$\therefore \boxed{y = x + 2a \quad \text{and} \quad y = -(x + 2a)}$
[{"qus_id":"3794","year":"2018"},{"qus_id":"3765","year":"2018"},{"qus_id":"3760","year":"2018"},{"qus_id":"3911","year":"2019"},{"qus_id":"3940","year":"2019"},{"qus_id":"9446","year":"2020"},{"qus_id":"10666","year":"2021"},{"qus_id":"10219","year":"2015"},{"qus_id":"10222","year":"2015"},{"qus_id":"10227","year":"2015"},{"qus_id":"11972","year":"2025"},{"qus_id":"11977","year":"2025"},{"qus_id":"10355","year":"2013"},{"qus_id":"10342","year":"2013"},{"qus_id":"3642","year":"2012"},{"qus_id":"16198","year":"2011"},{"qus_id":"16307","year":"2010"},{"qus_id":"4708","year":"2016"},{"qus_id":"4713","year":"2016"},{"qus_id":"18158","year":"2016"},{"qus_id":"18171","year":"2016"},{"qus_id":"19133","year":"2026"}]