Q21.The equation of a right circular cone with vertex at the origin the axis the z-axis and semi vertical angle 4 π is–
Correct answer: y2 + x2 = z2
Q22.The radius of sphere x2 + y2 + z2 + x + y + z = 4 is –
Correct answer: 19/2
Q23.The equation of the sphere passing through the origin and making intercepts 1, 3, 5 with the three coordinate axes is:
Correct answer: x2 + y2 + z2 – x – 3y – 5z = 0
Q24.The equation of the director sphere of the central conicoid 2 2 2 2 2 2 x y z + + = 1 a b c is
Correct answer: x2 + y2 + z2 = a2 + b2 + c2
EnglishUPPSC GIC 2021 UPPSC Ashram Paddhati 2021
Q25.The radius of the circle x2 + y2 + z2 – 8x + 4y + 8z – 45 = 0, x – 2y + 2z = 3 is-
Correct answer: 4 5
EnglishUPPSC GIC 2021 UPPSC Ashram Paddhati 2021 Rajasthan TGT 2011
Q26.The equation of the right circular cone, whose vertex is the origin, the axis is the z axis and semi- vertical angle is α, is-
Correct answer: x2 + y2 = z2 tan2 α
Q27.The equation of the sphere on the join of (2, –3, 1) and (3, –1, 2) as diameter is
Correct answer: x2 + y2 + z2 – 5x + 4y – 3z + 11 = 0
EnglishUP TGT 2021 UPPCS (Pre) 1997
Q28.The general equation to the cone of second degree which passes through the axes, is
Correct answer: fyz + gzx + hxy = 0
Q29.Find the equation of the cone with vertex at the origin and direction cosines of its generators satisfy the equation l2 + 2m2 – 3n2 = 0
Correct answer: x2 + 2y2 – 3z2 = 0
EnglishUPPSC Ashram Paddhati 2021 Rajasthan TGT 2015
Q30.Two spheres of radii r1 and r2 intersect each other orthogonally. The radius of the common circle is
Correct answer: 1 2 2 2 1 2 r r r + r
Q31.The equation x2 – 2y2 + 3z2 – 4xy + 5yz – 6zx + 8x – 19y – 2z – 20 = 0 represents a:
Correct answer: Cone
Q32.If the plane 2x – 2y + z = 9 touches the sphere x2 + y2 + z2 = r2, then the value of 'r' will be:
Correct answer: 3
Q33.A sphere 2 2 2 x + y + z = 9 is cut by the plane x + y + z = 3The radius of the circle so formed is:
Correct answer: 6
EnglishNVS PGT 10-06-2019
Q34.The radius of a sphere whose centre is (4, 4, –2) and which passes through the origin is:
Correct answer: 6
EnglishNVS PGT 10-06-2019
Q35.The equation of a sphere on the line joining the pints (1, 5, 6) and (–2, 1, 1) as diameter is:
Correct answer: x2 + y2 + z2 + x – 6y – 7z + 9 = 0
EnglishKVS PGT 23-12-2018
Q36.The equation of a sphere circumscribing a tetrahedron whose faces are x=0, y=0, z=0 and x y z 1 a b c + + = + + = + + = + + = is:
Correct answer: 2 2 2 x y z ax by cz 0 + + − − − =
EnglishUP PGT-2016 (02-02-2019)
Q37.Equation of a cone, whose vertex is at origin and base is the curve z= k, f(x,y)=0 is
Correct answer: xk yk f, 0 z z =
EnglishUP PGT-2016 (02-02-2019)
Q38.If 2x–y+z+4=0 is a tangent plane to the sphere whose centre is (1, 0, 1), then radius of sphere is
Correct answer: 7/6
EnglishUP PGT-2016 (02-02-2019)
Q39.In three dimensional geometry equation x2 +y2 =r2 represents a
Correct answer: cylinder
Q40.The radius of the sphere x2 +y2 +z2 –x – y– z=0 is
Correct answer: 3/2