Vector Calculus Chapter 01. If the linear velocity V — V=X is given by 2 yi+xyz j—yz 2 k then the angular 05. The expression curl (grad fi where . f is a scalar function is (GATE-96[MED velocity W at the point (1, 1, — 1) is (GATE-93) 02. The directional derivative of f(x, y) = 2x2 + 3y2 + z2 at point P(2, 1, 3) in the direction of the vector a = i - 21c is (GATE — 94) (a) 4 /15- (b) — 4 / (c) & /4 (d) — .15 /4 03. If V is a differentiable vector function andf (a) Equal to V2f (b) Equal to div(gradf ) (c) A scalar of zero magnitude (d) A vector of zero magnitude 06. The directional derivative of the function f(x,y,z) = x + y at the point P(1,1,0) along the direction i + j is (GATE — 96) (a) 1 /112 (b)Vi (c) — (d) 2 is sufficiently differentiable scalar function 07. For the function (I) = axe y — y3 to represent then curl (f V) = (GATE-95[MED (a) (grad f) x V + (f curl V) (b) o (c) f curl V the velocity potential of an ideal fluid, V2 (I) should be equal to zero. In that case, the value of 'a' has to be (GATE — 99) (a) —1 (b) 1 (c) —3 (d) 3 (d) (grad f)xV 04. The derivative of f(x, y) at point (1, 2) in the 08. Given a vector field F , the divergence theorem states that (GATE-02 DEED direction of vector i +j is 242 and in the (a) f F.ds = fV.Fdv direction of the vector —2 j is —3. Then the (b)SP. ds=i-VxFdv derivative of f(x, y) in direction —i — 2 j is (GATE — 95) (a) 2 -‘,/2 + 3/2 (b) — 7 /J (c) — 2 i — 3/2 (d) 1 / I.1(1 I mit ci (c) f Fxds=1V.Fdv (d) iFxds= SV.Fdv 'us „„)Flyderabadi Delhi I Bhopal' Pune Bhubaneswar Lucknow1Pama I Bengaluru I Chennai I Vllayawada I Vizag I Tirupati Kukatpally I Kolkata 4 4 ACE 4,z: Engineering Publications 9. : 63 : The directional derivative of the following function at (1, 2) in the direction of (4i+3j) is: f(x, y) = x2 + y2 (GATE — 02) (a) 4 /5 (b) 4 (c)2 /5 (d) 1 10. The vector field F = xi — y j (where i and j are unit vectors) is (GATE — 03) (a) divergence free, but not irrotational (b) irrotational, but not divergence free (c) divergence free and irrotational (d) neither divergence free nor irrotational 11. Value of the integral Vector Calculus (c) a line integral and a volume integral (d) gradient of a function and its surface integral. x 2 3/ 2 14. For the scalar field u = — 2 + — , the 3 magnitude of the gradient at the point (1, 3) is (GATE-05[EE]) (b) 9 2 xydy — y2 dx , where, 15. If a vector R(t) has a constant magnitude c is the square cut from the first quadrant by the line x = 1 and y = 1 will be (Use Green's theorem to change the line integral into double integral) (GATE — 05) (a) 1/2 (b) 1 (c) 3/2 (d) 5/3 then (GATE-0511[111) (a) R . dk =0 dt (c) R • R = dR dt (b) K x dR =0 dt (d) R x R = dk dt 12. The line integral I V.dr of the vector function V(r) = 2xyz i + x2 z j + x2 y k from the origin to the point P (1, 1, 1) (GATE'05) (a) (b) (c) (d) is 1 is zero is —1 cannot be determined without specifying the path 16. A scalar field is given by f = X23 + y2/3 , where x and y are the Cartesian coordinates. The derivative of 1' along the line y = x directed away from the origin at the point (8, 8) is (GATE-05[IN] ) -sh 13. Stokes theorem connects (GATE-05[ME]) (a) a line integral and a surface integral (b) a surface integral and a volume integral ACE Engineering Publications >Hyderabad I Delhi I Bhopal I Pune I Bhubaneswar l blallOW I Patna I Bengaluru Chennai I Vijayawada j Vizag I Tirupaii I Kukatpally I kolltata ACE Li Engineering Publicafions t 17. Which one of the following is Not associated with vector calculus? (GATE-05 [PI]) (a) Stoke's theorem (b) Gauss Divergence theorem (c) Green's theorem (d) Kennedy's theorem 22. The angle (in degrees) between two planar P (b) V2 /3 + V(V.P) (d) V (V.P)- V2 /3 23. Divergence of the vector field (GATE-05 [EC] (c) V 2 /3 + (V x P) 19. The directional derivative the f (x, y, z) =2x2 + 3y2 + z2 at of point p(2,1,3) in the direction of the vector a= 1 - - -1 a x bxc (c) 2 1 (d) -(a xb) •c . . vectors a = —1+ 1 j- and b = 1+ 1- j 2 2 2 2 (GATE-07 [PI]) is (a) 30 (b) 60 (c) 90 (d) 120 18. V x x P) where P is a vector is equal to (a) Px V xP- Engineering Mathematics : 64 : v(x, y, z) = -(x cosxy + y) i + (y cosxy) j + [(sinz2) + x2 + y2] is (GATE-07[EN) (a) 2z cosz2 (c) x sinxy - cosz (b) sin xy + 2z cosz2 (d) none of these i - 2k is (a) - 2.785 (c) - 1.789 (GATE-06[CE') (b) - 2.145 (d) 1.000 24. Consider points P and Q in xy - plane with P = (1, 0) and Q = (0, 1). The line integral 21 (x dx + y dy) along the semicircle with the 20. The velocity vector is given as v= 5xyi + 2y2 j + 3yz2 k. The divergence of this velocity vector at (1, 1, 1) is (GATE-07 ICE]) (a) 9 (b) 10 (c) 14 (d) 15 21. The area of a triangle formed by the tips of vectors a, b and c is (GATE-07[ME]) line segment PQ as its diameter (GATE-08 [EC]) (a) is -1 (b) is 0 (c) 1 (d) depends on the direction (clockwise (or) anti-clockwise) of the semi circle 25. The divergence of the vector field (a) (a - b) • (a - c) 2 (x - y)i + (y - x) j + (x + y + z)k is (b) I (a - b) x (a 2 (a) 0 (c) 2 (GATE-08 [ME]) (b) 1 (d) 3 ACE Engineering Publications I. yderabad I Delhi Bhopal I Pune I Bhubaneswar I Lucknow I Patna Bengaluru I Chennai I Vijayawada Vizag Tirupati I Kukatpally I Kolkata ACE :, Engineering Publications .0 g. s44•4 t:, : 65 : Vector Calculus e 26. The directional derivative of the scalar (a) fV.di=fi function f(x, y, z) = x2 + 2y2 + z at the point P = (1, 1, 2) in the direction of the vector a =3i-4j is (b) = ff cTs' s, (GATE-08 [ME]) (a) — 4 (b) —2 (c) —1 (d) 1 (ofvxV.di=fivxXZ sc (d) fvxA.di=f1 27. If r is the position vector of any point on a closed surface S that encloses the volume V then if (r • ds) is equal to (GATE-08[PI]) 31. A sphere of unit radius is centered at the origin. The unit normal at a point (x, y, z) on the surface of the sphere is the vector. (a) V (b) V (c) 2V (d) 3V 2 (GATE-09[IN]) (a) (x, y, z) ( 1 1 1 (b) „ 28. For a scalar function f(x, y, z) = x2+3y2+2z2, the gradient at the point P(1, 2, —1) is (GATE-09 [CE] (a) 2i + 6j + 4k (b) 2i +12j — 4k (c) 2i +12 j + 4k (d) 156. 29. For a scalar function f(x, y, z) = x2+3y2+2z2, (c) (d) x y z x y z Ah. 32. The divergence the directional derivative at the point 3xz i + 2xy — yz2 P(1, 2, —1) in the direction of a vector equal to - + 2k is (GATE-09ICED (a) —18 (b) —3 .4 (c) 3 Ai& (d) 18 30. If a vector field V is related to another field of the (GATE-09IECD Note: C and Sc refer to any closed contour field at a point (1, 1, 1) is (GATE-091111E1) (a) 7 (b) 4 (c) 3 (d) 0 33. F(x, y) = (x2 + xy) fix + (y2+xy) a y . Its line integral over the straight line from (x, y) = (0, 2) to (x, y) = (2, 0) evaluates to A through V=VxA, which of the following is true? vector (GATE-09 [EE]) (a) — 8 (b) 4 (c) 8 (d) 0 and any surface whose boundary is C. ACE Engineering Publications >Hyderabad I Delhi I Bhopal I Pune I Bhubaneswar I Lucknow I Patna Bengaluru I Chennai I Vijayawada Vizag Tirupati I Kukatpally I Kolkata 11$ di 4 rk %. '' ACE 34. The line integral of the vector function F = 2x i + x 2 31 along the x — axis from x = 1 to x = 2 is (a) 0 (c) 3 Engineering Mathematics : 66 : Engineering Publications (GATE-09 [PI]) (b) 2.33 (d) 5.33 vectors is perpendicular to both the (GATE-11 [PI]) vectors AB and BC . (a) 16i +9 j —12K (b) 16i-9 j+12k (c) 161-9j-12K (d) 16i+9 j+12K P2 35. Divergence of the 3 — dimensional radial vector field r is 39. The line integral f (ydx+ xdy) from (GATE-10[EE]) 1 (x1 y1 ) to P2 (x2, y2 ) along the semi-circle 1 (a) 3 (b) (c) 1 + 3+ k (d) +3+0 — PiP2 shown in the figure is (GATE-11[PI]) Y (a) x2 y2 — xi yi 36. If A = xy a•••• x + x 2 a y then A •cl I- over the (b) x2 2 (c) path shown in the figure is (y2 2, ) 4 (x2 2 .311 . (x 2 x i) (y2 i y1) (d) (Y2 — Y1)2 + (x 2 Y (x2 y2) — 1) P1 (x1 3, 2 ► 40. If T(x, y, z) = x2 + y2 + 2z2 defines the 3 temperature at any location (x, y, z) then the 2 0 x magnitude of the temperature gradient at point P(1, 1, 1) is Itsh 2/.1S (GATE-10[EC]) (GATE-11[PI]) (a) 2J (b) 4 (c) 24 (d) 37. If a and b are two arbitrary vectors with magnitudes a and b respectively, 41. Consider a closed surface 'S' surrounding a a x i)12 will be equal to (GATE-1110ED volume V. If r is the position vector of a (a) a2 b2 — (a . b)2 2 (c) a2 b2 +(a.b) (b) ab—a.b (d) ab+a.b 38. If A (0, 4, 3), B(0, 0, 0) and c(3, 0, 4) are there points defined in x, y, z coordinate system, then which one of the following ACE Engineering Publications point inside S with n the unit normal on S', the value of the integral ff5r.nds is (a) 3V (c) 10 V (GATE-11 [EC]) (b) 5V (d) 15 V ,,ultatpally I Kolkata yderabad I Delhi I Bhopal I Pune Bhubaneswar I Luclulow I Patna I Bengaluru I Chennai I Vijayawada I Vizag I Tirupati :1 V ACE 41 Engineering Publications : 67 : Vector Calculus 42. The two vectors [1, 1, 1] and [1, a, a2] where 46. Consider a vector field A-(f). The closed (GATE-111EED loop line integral A • dl can be expressed a = 21+j— 2 are (a) Orthonormal (c) Parallel as (b) orthogonal (d) Collinear (GATE - 20131ECI) (a) if (V x A) • ds over the closed surface bounded by the loop 43. The direction of vector A is radially outward from the origin, with lAl = K rn where r2 = x2 + y2 + z2 and K is constant. The value of n for which V. A = 0 is bounded by the loop (c) (GATE-12[EC, EE, IN]) (a) -2 (c) 1 (b) ficf (V • A)dv over the closed volume (b) 2 f f f (V • A)dv over the open volume bounded by the loop (d) Li (V x A) • ds over the open surface (d) 0 bounded by the loop 44. For the spherical surface x2 + y2 + z2 = 1, the unit outward normal vector at the point i Ln2 A = xa x + }Ta y + za, is (GATE - 20131ECI) 1_ oj is given by 2 (GATE-12[ME, PI]) (a) 1 1 j N/ 2 +2 .‘,/ (b) 47. The divergence of the vector field 1 •• i- 1j N/2 (a) 0 (c) 1 (b) 1/3 (d) 3 48. For a vector E, which one of the following statements is NOT TRUE? (c) (GATE - 20131IN1) (a) If V.E = 0, E is called solenoidal 45. For the parallelogram OPQR shown in the sketch. OP = a I+ b j and OR = ci+ d j . The area of the parallelogram is (GATE-12 [CE]) (b) If V x E = 0, E is called conservative (c) If V x E = 0, E is called irrotational (d) If V.E = 0, E is called irrotational Q (a) ad - bc (b) ac + bd (c) ad + bc (d) ab - cd )Hyderabad I Delhi 'Bhopal I Pune I Bhubaneswar) LucknowIPatna l Bengaluru I Chennai I Wayawada I Vizag iTirupati I Kukatpally I Kolkata 'Iglu( (111114 P111111( aill,111( 411 , ACE r,10 Engiaeeriug Publicafions Engineering Mathematics : 68 : 4. 49. The following surface integral is to be 53. The magnitude of the gradient for the evaluated over a sphere for the given steady function f (x , y, z) = x 2 + 3y2 +z3 velocity vector field F = xi + yj + zk defined point (1, 1, 1) is with respect to a Cartesian coordinate at the (GATE — 14 — EC — Set 4) system having i, j and k as unit base vectors. 54. The ff — 1 (F.n )dA 4 directional derivative of Where S is the sphere, x2+y2+z2 = 1 and n is Y + y) at (1, 1) in the direction f(x, y) = xr__ A/2 the outward unit normal vector to the sphere. of the unit vector at an angle of The value of the surface integral is (GATE — 2013[ME]) (a) TC (b) 27c (c) 3 m/4 (d) 4 n y — axis, is given by (GATE — 14 — EC — Set 4) 55. Given F = za x + xa y 50. The curl of the gradient of the scalar field — rc with 4 ya z . If S represents the portion of the sphere x2 + y 2 + z2 =1 defined by V = 2x2y + 3y2z + 4z2x is (GATE — 2013IEED for z 0, then f (V x F.Jds is (a) 4xyax + 6yzay + 8zxa7 (GATE — 14 — EC — Set 4) (b) 4a„ + 6ay + (c) (4xy+4z2)a„+(2x2 + 6yz)ay+ (3y2 + 8zx)a, (d) 0 56. The line integral of function F = yzi, in the counterclockwise direction, along the circle 51. Given a vector field F = y 2 xa x — yza y — x 2 a, , the line integral .I. F.d1 evaluated along a segment on the x- x2 + y2 = 1 at z= 1 is (GATE — 14 — EE — Set 1) (a) —27c (b) —IT (c) TC (d) 27c axis from x = 1 to x = 2 is (GATE — 2013 [EN) 57. Let V.(/' = x2 y + y2 z + z2 x, where f and (a) 2.33 (b) 0 V are scalar and vector fields respectively. (c) 2.33 (d) 7 If V = yi + zj + xk, then V.(Vf) is (GATE —14 — EE — Set 3) (a) x2 y + y2 z + z2 x 52. If r = xa x + ya y + za , and r = r, then div (b) 2xy + 2yz + 2zx (c) x + y+ z (r 2 V(1nr))= (d) 0 (GATE — 14 — EC — Set 2) ACE Engineering Publications )Hyderabad I Delhi I Bhopal I Pune I Bhubaneswar Lucknow I Patna I Bengaluru I Chennai I Vijayawada I Vizag I Tirupati I Kulcatpally I Kolkata yLL JJ ACE s4.4., & : 69 : Engineering Publications 58. A vector is defined as f = y 1+ x j+ z k Vector Calculus (a) 0 (c) 5 (b) 3 (d) 6 A A Where i , j , and k are unit vectors in cartesian (x,y,z) coordinate system.. The 41 surface integral of.ds over the closed surface S of a cube with vertices having the following coordinates: (0,0,0), (1,0,0), (0,1,0), (0,0,1), (1,0,1), (1,1,1), (0,1,1), (1,1,0) is (GATE —14 — IN — Set 1) 59. The integral (ydx — xdy) is evaluated along the circle x 2 y2 1 =— traversed in 4 counter clockwise direction. The integral is equal to (GATE — 14 — ME — Set 1) (a) 0 (c)— (b) — (d) 2 4 4 60. Curl of vector f = x2z2i-2xy2ij+ 2y2z3k is (GATE — 14 — ME — Set 2) (a) (4yz3 + 2 xy2 + 2 x2z3 2y2A (b) yzi + 2 xy2 2x2;j 2y2zi (c) 2xz21 —4xyzj+ 6y2z2k 62. A particle moves along a curve whose parametric equations are: x=t3+2t, y = —3e-21 and z = 2 sin (5t), where x, y and z show variations of the distance covered by the particle (in cm) with time t (in s). The magnitude of the acceleration of the particle (in cm/s2) at t = 0 is (GATE-14—CE—Set 1) 63. Directional derivative of (I) = 2xz—y2' at the point (1, 3, 2) becomes maximum in the direction of (GATE —14 —PI— Set 1) (a) 4i+2j-3k (b) 4i-6j+2k (c) 2i-6j+2k (d) 4i-6j-2k 64. If 4 = 2x3y2z4 then V24'is (GATE 14 — PI — Set 1) 2z4+4x2z4+ (a) 12xy 20x3y2z3 (b) 2x2y2z+4x3z4+24x3y2z2 (c) 12xy2z4+4x3z4+24x3y2z2 (d) 4xy2z+4x2z4+24x3y2z2 65. The directional derivative of the field u(x,y,z) = x-3yz in the direction of the 1 vector ( + j 2 k) at point (2,-1,4) is (d) 2xz2i + 4xyzj + 6y2z2k (GATE-15—CE—Set 1) 61. Divergenece of the vector field x2zi + xy3 yz2k at (1, —1, 1) is (GATE — 14 — ME — Set 3) A('E Engiuccriug Publications 'Delhi IBhopallPune I Bhubaneswar I Lucknow1PatnalBengalumIChennai I VijayawadalVizag rriruPati I KukatPally1 Kolkata ..td. ACE Engineering Mathematics : 70 : Fziginecing Publications 4.) ay _ (b) 515 x2yz a7 . Which one of the following (d) 9k 66. A vector P is given by P = x3y a, — x2y2 statements is TRUE? (GATE — 15 — EC — Set 1) (a) P is solenoidal, but not irrotational (b) P is irrotational, but not solenoidal (c) P is neither solenoidal nor irrotational (d) P is both solenoidal and irrotational (c) Div Curl P = 0 (d) Div (0P)= 0DivP Q. Gauss's Theorem R. Divergence Theorem S. Cauchy's Integral Theorem List-II 2. f(z)dz = 0 [(3x-8y2)dx + (4y-6xy)dy], (where C is 71. The velocity field on an incompressible flow 3. fff ( v .A)dv = ff A.ds 4. ff (v xA).ds = A . d / (GATE —15 — EE — Set 2) 1 3 4 70. The value of the region bounded by x=0, y=0 and x+y=1) . (GATE — 15 — ME — Set 3) is 1.ff D.ds = Q 1 vector valued function in a threedimensional space. Which one of the following is an identity? (GATE — 15 — ME — Set 3) (b) DivP = 0 List-I P. Stoke's Theorem Q scalar function and V be an arbitrary smooth (a) Curl(ili = V(0DivP) 67. Match the following. Codes: P (a) 2 (b) 4 (c) 4 (d) 3 69. Let 0 be an arbitrary smooth real valued R 4 3 1 2 S 3 2 2 1 68. The magnitude of the directional derivative of the function f(x,y)= x2+3y2 in a direction normal to the circle x2 +y2 =2, at the point (GATE — 15 — IN — Set 2) (1,1), is is given by V = (aix + a2y +a3z) i + (bix + b2y b3z) + (cix + c2y + c3z) k, where al = 2 and c3 = —4 . The value of b2 is (GATE —15 — ME — Set 1) 72. Curl of vector V(x,y,x) = 2x2i + 3z2 j +y3k at x= y = z = 1 is (GATE — 15 —ME — Set 2) (b) 3i (a) —3i (c) 3i — 4j (d) 3i — 6k iyderabad I Delhi I Bhopal I Pune I Bhubaneswar I LucknowIPatna I Bengaluru I Chennai I Vijayawada I Vizag I llrupati I Kukarpally I Kolkata Ifs., & ACE : 71 : Engineering Publkations 1 73. The surface integral if — (9xi — 33/j) • n dS TC over the sphere given by x2 + y2 + z2 9 is (GATE — 15 — M E — Set 2) 74. The value of line integral Vector Calculus The value of the integral is (GATE-16-ME-SET2) 78. The value of the line integral f F.rds, where C is a circle of radius units is f (2xy2dx + 2x2ydy + dz) along a path Here, F(x, y) = yl + 2x j and r is the UNIT joining the origin (0, 0, 0) and the point (1, 1, 1) is (GATE — 16 — EE — Set 2) (a) 0 (b) 2 (c) 4 (d) 6 75. The line integral of the vector field tangent vector on the curve C at an arc length s from a reference point on the curve. and j are the basis vectors in the x-y Cartesian reference. In evaluating the line integral, the curve has to be traversed in the counter-clockwise direction. (GATE-16-ME-SET3) F = 5xz i + (3x2 +2y) j +x2z k along a path from (0, 0, 0) to (1, 1, 1) parameterized by (t, t2, t) is (GATE — 16 — EE — Set 2) 76. The vector that is NOT perpendicular to the vectors (i + j + k) and (i + 2j + 3k) (GATE —16—IN) is (a) (i — 2j + k) (1)) (—i + 2j — k) (c) (Oi + Oj + Ok) (d) (4i + 3j + 5k) 77. A scalar potential 9 has the following gradient: VT = yzi + xzj + xyk . Consider the integral LV(p.cif r= on ,t the curve + yj + zk . The curve C is 79. Suppose C is the closed curve defined as the circle x2 + y2 = 1 with C oriented anticlockwise. The value of 2 2 (xy dx + x ydy) over the curve f equals . (GATE — 16 — EC — Set 2) 80. The smaller angle (in degrees) between the planes x + y + z = 1 and 2x — y + 2z = 0 is (GATE-17—EC) 81. If the function P.a.(3y—kiz)+ay(k2x-2z)— az(k3y + z) is irrotatiotial, then the values of the constants kl, k2 and k3 respectively, are parameterized as follows: x=t y = t2 and 1 t z = 3t2 vector (a) 0.3, —2.5, 0.5 (c) 0.3, 0.33, 0.5 (GATE-17—EC) (b) 0.0, 3.0, 2.0 (d) 4.0, 3.0, 2.0 I Delhi I Bhopal I Pune I Bhubaneswar LucknowiPatrialBengaluruiChennailVijayawadalVing airupati I Kukarpalty I KolkataACE Engineering Publications 45Hyderabad „. '`..? Oe ACE : 72 : Fagineaing Publications lo 82. Let I = (2z dx+2y dy + 2x dz) where x, y , z are real , and let C be the straight line segment from point A: (0,2, 1 ) to point B: (4,1,-1) . The value of I is (GATE-17—EC) 83. For the vector V = 2yzi + 3xzj + 4xyk, the Engineering Mathematics where F = (x+y)I + (x+z)j + (y+z)k and n is the unit outward surface normal, yields (GATE-17—ME) 85. The divergence of the vector field V = x2i + 2y3 j+z4 katx= 1,y= 2,z= 3 is (GATE-17—CE) value of v.(v x ) is (GATE-17—ME) 84. The surface integral LI.F.ndS over the surface S of the sphere x2 + y-2 + ACE Engineering Publications z2 = 9, yderabadiDelhilBhopallPurtelBhubaneswarl LucknowiPatnalBengalurulChennailVijayawadaiVizag ITirupati Kukatpally1 Kolkata