Explore topic-wise MCQs in Joint Entrance Exam - Main (JEE Main).

This section includes 8666 Mcqs, each offering curated multiple-choice questions to sharpen your Joint Entrance Exam - Main (JEE Main) knowledge and support exam preparation. Choose a topic below to get started.

7551.

The triangle formed by the points (0, 7, 10), (?1, 6, 6), (? 4, 9, 6) is [RPET 2001]

A. Equilateral
B. Isosceles
C. Right angled
D. Right angled Isosceles
Answer» E.
7552.

The points \[A(5,\,-1,\,\,1)\]; \[B\,(7,-4,\,7);\] \[C(1,\,-6,\,10)\] and \[D(-1,-3,\,4)\] are vertices of a [RPET 2000]

A. Square
B. Rhombus
C. Rectangle
D. None of these
Answer» C. Rectangle
7553.

The direction cosines of the normal to the plane \[3x+4y+12z=52\] will be [MP PET 1997]

A. 3, 4, 12
B. ? 3, ? 4, ? 12
C. \[\frac{3}{13},\frac{4}{13},\frac{12}{13}\]
D. \[\frac{3}{\sqrt{13}},\frac{4}{\sqrt{13}},\frac{12}{\sqrt{13}}\]
Answer» D. \[\frac{3}{\sqrt{13}},\frac{4}{\sqrt{13}},\frac{12}{\sqrt{13}}\]
7554.

The co-ordinates of the point which divides the join of the points (2, ?1, 3) and (4, 3, 1) in the ratio 3 : 4 internally are given by [MP PET 1997]

A. \[\frac{2}{7},\frac{20}{7},\frac{10}{7}\]
B. \[\frac{15}{7},\frac{20}{7},\frac{3}{7}\]
C. \[\frac{10}{7},\frac{15}{7},\frac{2}{7}\]
D. \[\frac{20}{7},\frac{5}{7},\frac{15}{7}\]
Answer» E.
7555.

The plane \[XOZ\] divides the join of \[(1,\,-1,\,\,5)\] and (2, 3, 4) in the ratio \[\lambda :1\], then \[\lambda \] is [JET 1988]

A. ? 3
B. 3
C. \[-\frac{1}{3}\]
D. \[\frac{1}{3}\]
Answer» E.
7556.

The projection of the line segment joining the points (?1, 0, 3) and (2, 5, 1) on the line whose direction ratios are 6, 2, 3 is [AI CBSE 1985]

A. \[\frac{10}{7}\]
B. \[\frac{22}{7}\]
C. \[\frac{18}{7}\]
D. None of these
Answer» C. \[\frac{18}{7}\]
7557.

If the sum of the squares of the distance of a point from the three co-ordinate axes be 36,then its distance from the origin is

A. 6
B. \[3\sqrt{2}\]
C. \[2\sqrt{3}\]
D. None of these
Answer» C. \[2\sqrt{3}\]
7558.

If \[A\,(1\,,\,\,2,\,\,-1)\] and \[B(-1,\,\,0,\,\,1)\] are given, then the co-ordinates of P which divides \[AB\] externally in the ratio\[1:2\], are [MP PET 1989]

A. \[\frac{1}{3}(1,\,4,-1)\]
B. (3, 4, ?3)
C. \[\frac{1}{3}(3,\,4,-3)\]
D. None of these
Answer» C. \[\frac{1}{3}(3,\,4,-3)\]
7559.

The direction cosines of the line \[x=y=z\] are [MP PET 1989]

A. \[\frac{1}{\sqrt{3}},\frac{1}{\sqrt{3}},\frac{1}{\sqrt{3}}\]
B. \[\frac{1}{3},\frac{1}{3},\frac{1}{3}\]
C. 1, 1, 1
D. None of these
Answer» B. \[\frac{1}{3},\frac{1}{3},\frac{1}{3}\]
7560.

The centre of sphere passes through four points (0, 0, 0), (0, 2, 0), (1, 0, 0) and (0, 0, 4) is [MP PET 2002]

A. \[\left( \frac{1}{2},\,1,\,2 \right)\]
B. \[\left( -\frac{1}{2},\,1,\,2 \right)\]
C. \[\left( \frac{1}{2},\,1,-\,2 \right)\]
D. \[\left( 1,\frac{1}{2},\,2 \right)\]
Answer» B. \[\left( -\frac{1}{2},\,1,\,2 \right)\]
7561.

Equation \[a{{x}^{2}}+b{{y}^{2}}+c{{z}^{2}}+2fyz+2gxz+2hxy\] \[+2ux+2vy+2wz+d=0\]represents a sphere, if [MP PET 1990]

A. \[a=b=c\]
B. \[f=g=h=0\]
C. \[v=u=w\]
D. \[a=b=c\] and \[f=g=h=0\]
Answer» E.
7562.

How many different sphere of radius ?r? can be drawn which touches all the three co-ordinate axes

A. 4
B. 2
C. 6
D. 8
Answer» E.
7563.

Equation of the plane through the mid-point of the line segment joining the points P(4, 5, -10) and Q(-1, 2, 1) and perpendicular to PQ is

A. \[\vec{r}.\left( \frac{3}{2}\hat{i}+\frac{7}{2}\hat{j}-\frac{9}{2}\hat{k} \right)=45\]
B. \[\vec{r}.\left( -\hat{i}+2\hat{j}-\hat{k} \right)=\frac{135}{2}\]
C. \[\vec{r}.(5\hat{i}+3\hat{j}-11\hat{k})+\frac{135}{2}=0\]
D. \[\vec{r}.(5\hat{i}+3\hat{j}-11\hat{k})=\frac{135}{2}\]
Answer» E.
7564.

The perpendicular distance of P (1, 2, 3) form the lie \[\frac{x-6}{3}=\frac{y-7}{2}=\frac{z-7}{-2}\] is

A. 7
B. 5
C. 0
D. 6
Answer» B. 5
7565.

What is the angle between the lines\[\frac{x-2}{1}=\frac{y+1}{-2}\] and \[\frac{x-1}{1}=\frac{2y+3}{3}=\frac{z+5}{2}?\]

A. \[\frac{\pi }{2}\]
B. \[\frac{\pi }{3}\]
C. \[\frac{\pi }{6}\]
D. None of the above
Answer» B. \[\frac{\pi }{3}\]
7566.

If O, P are the points (0, 0, 0), (2, 3, -1) respectively, then what is the equation to the plane through P at right angles to OP?

A. \[2x+3y+z=16\]
B. \[2x+3y-z=14\]
C. \[2x+3y+z=14\]
D. \[2x+3y-z=0\]
Answer» C. \[2x+3y+z=14\]
7567.

The plane \[2x-3y+6z-11=0\] makes an angle \[{{\sin }^{-1}}(a)\] with the x-axis. Then the value of a is-

A. \[\frac{\sqrt{3}}{2}\]
B. \[\frac{\sqrt{2}}{3}\]
C. \[\frac{3}{7}\]
D. \[\frac{2}{7}\]
Answer» E.
7568.

A variable plane passes through a fixed point (1, 2, 3). The locus of the foot of the perpendicular from the origin to this plane is given by

A. \[{{x}^{2}}+{{y}^{2}}+{{z}^{2}}-14=0\]
B. \[{{x}^{2}}+{{y}^{2}}+{{z}^{2}}+x+2y+3z=0\]
C. \[{{x}^{2}}+{{y}^{2}}+{{z}^{2}}-x-2y-3z=0\]
D. None of these
Answer» D. None of these
7569.

If \[{{l}_{1}},{{m}_{1}},{{n}_{1}}\] and \[{{l}_{2}},{{m}_{2}},{{n}_{2}}\] are direction consines of the two lines inclined to each other at an angle \[\theta \], the direction cosines of the bisector of the angle between these lines are

A. \[\frac{{{l}_{1}}-{{l}_{2}}}{2\sin \frac{\theta }{2}},\frac{{{m}_{1}}-{{m}_{2}}}{2\sin \frac{\theta }{2}},\frac{{{n}_{1}}-{{n}_{2}}}{2\sin \frac{\theta }{2}}\]
B. \[\frac{{{l}_{1}}-{{l}_{2}}}{2\cos \frac{\theta }{2}},\frac{{{m}_{1}}-{{m}_{2}}}{2\cos \frac{\theta }{2}},\frac{{{n}_{1}}-{{n}_{2}}}{2\cos \frac{\theta }{2}}\]
C. \[\frac{{{l}_{1}}-{{l}_{2}}}{2\sin \frac{\theta }{2}},\frac{{{m}_{1}}-{{m}_{2}}}{2\sin \frac{\theta }{2}},\frac{{{n}_{1}}-{{n}_{2}}}{2\sin \frac{\theta }{2}}\]
D. \[\frac{{{l}_{1}}-{{l}_{2}}}{2\cos \frac{\theta }{2}},\frac{{{m}_{1}}-{{m}_{2}}}{2\cos \frac{\theta }{2}},\frac{{{n}_{1}}-{{n}_{2}}}{2\cos \frac{\theta }{2}}\]
Answer» D. \[\frac{{{l}_{1}}-{{l}_{2}}}{2\cos \frac{\theta }{2}},\frac{{{m}_{1}}-{{m}_{2}}}{2\cos \frac{\theta }{2}},\frac{{{n}_{1}}-{{n}_{2}}}{2\cos \frac{\theta }{2}}\]
7570.

The vector equation of the line of intersection of the planes \[\vec{r}=\vec{b}+{{\lambda }_{1}}(\vec{b}-\vec{a})+{{\mu }_{1}}(\vec{a}-\vec{c})\] and \[\vec{r}=\vec{b}+{{\lambda }_{2}}(\vec{b}-\vec{c})+{{\mu }_{2}}(\vec{a}+\vec{c})\vec{a},\vec{b},\vec{c}\] being non-coplanar vectors, is

A. \[\vec{r}=\vec{b}+{{\mu }_{1}}(\vec{a}+\vec{c})\]
B. \[\vec{r}=\vec{b}+{{\lambda }_{1}}(\vec{a}-\vec{c})\]
C. \[\vec{r}=2\vec{b}+{{\lambda }_{2}}(\vec{a}-\vec{c})\]
D. None of these
Answer» B. \[\vec{r}=\vec{b}+{{\lambda }_{1}}(\vec{a}-\vec{c})\]
7571.

If lines \[x=y=z\] and \[x=\frac{y}{2}=\frac{z}{3}\] and third line passing through (1, 1, 1) form a triangle of area \[\sqrt{6}\] units, then the point of intersection of third line with the second line will be

A. \[(1,2,3)\]
B. \[(2,4,6)\]
C. \[\left( \frac{4}{3},\frac{8}{3},\frac{12}{3} \right)\]
D. None of these
Answer» C. \[\left( \frac{4}{3},\frac{8}{3},\frac{12}{3} \right)\]
7572.

A mirror and a source of light are situated at the origin 0 and at a point on OX respectively. A ray of light from the source strikes the mirror and is reflected. If the direction ratios of the normal to the plane are 1, -1, 1, then direction consines of the reflected rays are

A. \[\frac{1}{3},\frac{2}{3},\frac{2}{3}\]
B. \[-\frac{1}{3},\frac{2}{3},\frac{2}{3}\]
C. \[-\frac{1}{3},\frac{2}{3},-\frac{2}{3}\]
D. \[-\frac{1}{3},-\frac{2}{3},\frac{2}{3}\]
Answer» E.
7573.

What is the value of n so that the angle between the lines having direction ratios (1, 1, 1) and (1, -1, n) is \[60{}^\circ \]?

A. \[\sqrt{3}\]
B. \[\sqrt{6}\]
C. 3
D. None of these
Answer» C. 3
7574.

A plane passing through (1, 1, 1) cuts positive direction of coordinate axes at A, B and C, then the volume of tetrahedron OABC satisfies

A. \[V\le \frac{9}{2}\]
B. \[V\ge \frac{9}{2}\]
C. \[V=\frac{9}{2}\]
D. None of these
Answer» C. \[V=\frac{9}{2}\]
7575.

Under what condition does the equation \[{{x}^{2}}+{{y}^{2}}+{{z}^{2}}+2uc+2uy+2wz+d=0\] represent a real sphere?

A. \[{{u}^{2}}+{{v}^{2}}+{{w}^{2}}={{d}^{2}}\]
B. \[{{u}^{2}}+{{v}^{2}}+{{w}^{2}}>d\]
C. \[{{u}^{2}}+{{v}^{2}}+{{w}^{2}}<d\]
D. \[{{u}^{2}}+{{v}^{2}}+{{w}^{2}}<{{d}^{2}}\]
Answer» C. \[{{u}^{2}}+{{v}^{2}}+{{w}^{2}}<d\]
7576.

A line makes \[45{}^\circ \] with positive x-axis and makes equal angles with positive y, z axes, respectively. What is the sum of the three angles which the line makes with positive x, y and z axes?

A. \[180{}^\circ \]
B. \[165{}^\circ \]
C. \[150{}^\circ \]
D. \[135{}^\circ \]
Answer» C. \[150{}^\circ \]
7577.

What is the distance between the planes\[x-2y+z-1=0\] and\[-3x+6y-3z+2=0\]?

A. 3 unit
B. 1 unit
C. 0
D. None of the above
Answer» E.
7578.

The vector \[\vec{a}=\alpha \hat{i}+2\hat{j}+\beta \hat{k}\] lies in the plane of the vectors \[\vec{b}=\hat{i}+\hat{j}\] and \[\vec{c}=\hat{j}+\hat{k}\] and bisects the angle between \[\vec{b}\] and\[\vec{c}\]. Then which one of the following gives possible values of a and b?

A. \[\alpha =2,\beta =2\]
B. \[\alpha =1,\beta =2\]
C. \[\alpha =2,\beta =1\]
D. \[\alpha =2,\beta =1\]
Answer» E.
7579.

Consider the following relations among the angles\[\alpha \], \[\beta \] and \[\gamma \] made by a vector with the coordinate axes I. \[\cos 2\alpha +\cos 2\beta +\cos 2\gamma =-1\] II. \[{{\sin }^{2}}\alpha +{{\sin }^{2}}\beta +{{\sin }^{2}}\gamma =1\] Which of the above is/are correct?

A. Only I
B. Only II
C. Both I and II
D. Neither I nor II
Answer» B. Only II
7580.

Under which one of the following condition will the two planes \[x+y+z=7\] and\[\alpha x+\beta y+\gamma z=3\], be parallel (but not coincident)?

A. \[\alpha =\beta =\gamma =1only\]
B. \[\alpha =\beta =\gamma =\frac{3}{7}only\]
C. \[\alpha =\beta =\gamma \]
D. None of the above
Answer» D. None of the above
7581.

The foot of the perpendicular from the point (1, 6, 3) to the line \[\frac{x}{1}=\frac{y-1}{2}=\frac{z-2}{3}\] is

A. (1, 2, 5)
B. (-1, -1, -1)
C. (2, 5, 8)
D. (-2, -3, -4)
Answer» B. (-1, -1, -1)
7582.

Under what condition do \[\left\langle \frac{1}{\sqrt{2}},\frac{1}{2},k \right\rangle \] represent direction cosines of a line?

A. \[k=\frac{1}{2}\]
B. \[k=-\frac{1}{2}\]
C. \[k=\pm \frac{1}{2}\]
D. K can take any value
Answer» D. K can take any value
7583.

A line makes angles \[\theta ,\phi \] and \[\psi \] with x, y, z axes respectively. Consider the following 1. \[{{\sin }^{2}}\theta +{{\sin }^{2}}\phi ={{\cos }^{2}}\psi \] 2. \[{{\cos }^{2}}\theta +{{\cos }^{2}}\phi ={{\sin }^{2}}\psi \] 3. \[{{\sin }^{2}}\theta +{{\cos }^{2}}\phi ={{\cos }^{2}}\psi \] Which of the above is/are correct?

A. 1 only
B. 2 only
C. 3 only
D. 2 and 3
Answer» C. 3 only
7584.

Which one of the following is the plane containing the lien \[\frac{x-2}{2}=\frac{y-3}{3}=\frac{z-4}{5}\] and parallel to z axis?

A. \[2x-3y=0\]
B. \[5x-2z=0\]
C. \[5y-3z=0\]
D. \[3x-2y=0\]
Answer» E.
7585.

The angle between the line \[\frac{x-2}{a}=\frac{y-2}{b}=\frac{z-2}{c}\] and the plane \[ax+by+cz+6=0\] is

A. \[{{\sin }^{-1}}\left( \frac{1}{\sqrt{{{a}^{2}}+{{b}^{2}}+{{c}^{2}}}} \right)\]
B. \[45{}^\circ \]
C. \[60{}^\circ \]
D. \[90{}^\circ \]
Answer» E.
7586.

The angle between the straight lines \[\vec{r}=(2-3t)\vec{i}+(1+2t)\vec{j}+(2+6t)\vec{k}\] and \[\vec{r}=(1+4s)\vec{i}+(2-s)\vec{j}+(8s-1)\vec{k}\]is

A. \[{{\cos }^{-1}}\left( \frac{\sqrt{41}}{34} \right)\]
B. \[{{\cos }^{-1}}\left( \frac{21}{34} \right)\]
C. \[{{\cos }^{-1}}\left( \frac{43}{63} \right)\]
D. \[{{\cos }^{-1}}\left( \frac{34}{63} \right)\]
Answer» E.
7587.

The direction consines of two lines are related by\[l+m+n=0\]\[a{{l}^{2}}+b{{m}^{2}}+c{{n}^{2}}=0\]. The lines are parallel if

A. \[a+b+c=0\]
B. \[{{a}^{-1}}+{{b}^{-1}}+{{c}^{-1}}=0\]
C. \[a=b=c\]
D. None of these
Answer» C. \[a=b=c\]
7588.

Value of\[\lambda \] such that the line\[\frac{x-1}{2}=\frac{y-1}{3}=\frac{z-1}{\lambda }\]Is perpendicular to normal to the plane\[\vec{r}.(2\vec{i}+3\vec{j}+4\vec{k})=0\] is

A. \[-\frac{13}{4}\]
B. \[-\frac{17}{4}\]
C. \[4\]
D. None of these
Answer» B. \[-\frac{17}{4}\]
7589.

The equation of the plane which passes through the line of intersection of planes \[\vec{r}.{{\vec{n}}_{1}}={{q}_{1}},\vec{r}.{{\vec{n}}_{2}}=q\] And is parallel to the line of intersection of planes \[\vec{r}.{{\vec{n}}_{3}}={{q}_{3}}\] and \[\vec{r}.{{\vec{n}}_{4}}={{q}_{4}}\]is

A. \[[{{\vec{n}}_{2}}{{\vec{n}}_{3}}{{\vec{n}}_{4}}](\vec{r}.{{\vec{n}}_{1}}-{{\vec{q}}_{1}})=[{{\vec{n}}_{1}}{{\vec{n}}_{3}}{{\vec{n}}_{4}}](\vec{r}.{{\vec{n}}_{2}}-{{\vec{q}}_{2}})\]
B. \[[{{\vec{n}}_{1}}{{\vec{n}}_{2}}{{\vec{n}}_{4}}](\vec{r}.{{\vec{n}}_{4}}{{q}_{4}})=[{{\vec{n}}_{4}}{{\vec{n}}_{3}}{{\vec{n}}_{1}}](\vec{r}.{{\vec{n}}_{2}}-{{q}_{2}})\]
C. \[[{{\vec{n}}_{4}}{{\vec{n}}_{3}}{{\vec{n}}_{1}}](\vec{r}.{{\vec{n}}_{4}}-{{q}_{4}})=[{{\vec{n}}_{1}}{{\vec{n}}_{2}}\vec{n} 3](\vec{r}.{{\vec{n}}_{2}}={{q}_{2}})\]
D. None of these
Answer» B. \[[{{\vec{n}}_{1}}{{\vec{n}}_{2}}{{\vec{n}}_{4}}](\vec{r}.{{\vec{n}}_{4}}{{q}_{4}})=[{{\vec{n}}_{4}}{{\vec{n}}_{3}}{{\vec{n}}_{1}}](\vec{r}.{{\vec{n}}_{2}}-{{q}_{2}})\]
7590.

If the straight line \[\frac{x-{{x}_{0}}}{\ell }=\frac{y-{{y}_{0}}}{m}=\frac{z-{{z}_{0}}}{n}\] is parallel to the plane \[ax+by+cz+d=0\]then which one of the following is correct?

A. \[\ell +m+n=0\]
B. \[a+b+c=0\]
C. \[\frac{a}{\ell }+\frac{b}{m}+\frac{c}{n}=0\]
D. \[a\ell +bm+cn=0\]
Answer» E.
7591.

The foot of the perpendicular drawn from the origin to a plane is the point (1,-3, 1). What is the intercept cut on the x-axis by the plane?

A. 1
B. 3
C. \[\sqrt{11}\]
D. 11
Answer» E.
7592.

If the center of the sphere \[a{{x}^{2}}+b{{y}^{2}}+c{{z}^{2}}-2x+4y+2z-3=0\]is \[(1/2,-1,-1/2)\], what is the value of b ?

A. 1
B. -1
C. 2
D. -2
Answer» D. -2
7593.

The equation of the line which passes through the point (1, 1, 1) and intersect the lines \[\frac{x-1}{2}=\frac{y-2}{3}=\frac{z-3}{4}\] and \[\frac{x+2}{1}=\frac{y-3}{2}=\frac{z+1}{4}\] is

A. \[\frac{x-1}{3}=\frac{y-1}{10}=\frac{z-1}{17}\]
B. \[\frac{x-1}{3}=\frac{y-1}{3}=\frac{z-1}{-5}\]
C. \[\frac{x-1}{-2}=\frac{y-1}{1}=\frac{z-1}{-4}\]
D. \[\frac{x-1}{8}=\frac{y-1}{-2}=\frac{z-1}{3}\]
Answer» B. \[\frac{x-1}{3}=\frac{y-1}{3}=\frac{z-1}{-5}\]
7594.

If the plane \[2ax-3ay+4az+6=0\] passes through the midpoint of the line joining the centres of the spheres \[{{x}^{2}}+{{y}^{2}}+{{z}^{2}}+6x-8y-2z=13\] and \[{{x}^{2}}+{{y}^{2}}+{{z}^{2}}-10x+4y-2z=8\] then a equals

A. -1
B. 1
C. -2
D. 2
Answer» D. 2
7595.

The direction cosines l, m, n of two lines are connected by the relations l + m + n = 0, lm = 0, then the angle between them is:

A. \[\pi /3\]
B. \[\pi /4\]
C. \[\pi /2\]
D. 0
Answer» B. \[\pi /4\]
7596.

If \[\overset{\to }{\mathop{r}}\,=(\hat{i}+2\hat{j}+3\hat{k})+\lambda (\hat{i}+\hat{j}+\hat{k})\] and \[\overset{\to }{\mathop{r}}\,=(\hat{i}+2\hat{j}+3\hat{k})+\mu (\hat{i}+\hat{j}-\hat{k})\] are two lines, then the equation of acute angle bisector of two lines is

A. \[\overset{\to }{\mathop{r}}\,=(\hat{i}+2\hat{j}+3\hat{k})+t(\hat{j}-\hat{k})\]
B. \[\overset{\to }{\mathop{r}}\,=(\hat{i}+2\hat{j}+3\hat{k})+t(2\hat{i})\]
C. \[\overset{\to }{\mathop{r}}\,=(\hat{i}+2\hat{j}+3\hat{k})+t(\hat{j}+\hat{k})\]
D. None of these
Answer» B. \[\overset{\to }{\mathop{r}}\,=(\hat{i}+2\hat{j}+3\hat{k})+t(2\hat{i})\]
7597.

What are the direction ratios of the line determined by the planes \[x-y+2z=1\] and\[x+y-z=3\]?

A. (-1, 3, 2)
B. (-1, -3, 2)
C. (2, 1, 3)
D. (2, 3, 2)
Answer» B. (-1, -3, 2)
7598.

What are the direction cosines of a line which is equally inclined to the positive directions of the axes?

A. \[\left\langle \frac{1}{\sqrt{3}},\frac{1}{\sqrt{3}},\frac{1}{\sqrt{3}} \right\rangle \]
B. \[\left\langle -\frac{1}{\sqrt{3}},\frac{1}{\sqrt{3}},\frac{1}{\sqrt{3}} \right\rangle \]
C. \[\left\langle -\frac{1}{\sqrt{3}},-\frac{1}{\sqrt{3}},\frac{1}{\sqrt{3}} \right\rangle \]
D. \[\left\langle \frac{1}{3},\frac{1}{3},\frac{1}{3} \right\rangle \]
Answer» B. \[\left\langle -\frac{1}{\sqrt{3}},\frac{1}{\sqrt{3}},\frac{1}{\sqrt{3}} \right\rangle \]
7599.

From a point \[P(\lambda ,\lambda ,\lambda ),\] perpendiculars PQ and PR are drawn, respectively, on the lines \[y=x,\text{ }z=1\] and \[y=-x,\text{ }z=-1\]. If \[\angle QPR\] is a right angle, then the possible value(s) of \[\lambda \] is/are

A. 2
B. 1
C. -1
D. \[-\,\sqrt{2}\]
Answer» D. \[-\,\sqrt{2}\]
7600.

A plane passes through a fixed point (a, b, c). The locus of the foot of the perpendicular to it from the origin is the sphere

A. \[{{x}^{2}}+{{y}^{2}}+{{z}^{2}}-ax-by-cz=0\]
B. \[{{x}^{2}}+{{y}^{2}}+{{z}^{2}}-2ax-2by-2cz=0\]
C. \[{{x}^{2}}+{{y}^{2}}+{{z}^{2}}-4ax-4by-4cz=0\]
D. None of these
Answer» B. \[{{x}^{2}}+{{y}^{2}}+{{z}^{2}}-2ax-2by-2cz=0\]