| Matching Items MCQs for Sub-Topics of Topic 12: Vectors & Three-Dimensional Geometry Content On This Page | ||
|---|---|---|
| Vector Algebra: Introduction and Basic Operations | Components of a Vector and Linear Combinations | Scalar (Dot) Product of Vectors |
| Vector (Cross) Product of Vectors | Scalar Triple Product | Section Formula in Vector Algebra |
| Three Dimensional Geometry: Introduction and Lines | Three Dimensional Geometry: Planes | Three Dimensional Geometry: Angles |
| Three Dimensional Geometry: Distances | ||
Matching Items MCQs for Sub-Topics of Topic 12: Vectors & Three-Dimensional Geometry
Vector Algebra: Introduction and Basic Operations
Question 1. Match the type of vector with its definition or property.
(i) Unit Vector
(ii) Zero Vector
(iii) Collinear Vectors
(iv) Coinitial Vectors
(v) Equal Vectors
(a) Have the same initial point.
(b) Magnitude is 1.
(c) Lie on the same line or parallel lines.
(d) Magnitude is 0.
(e) Have same magnitude and direction.
Answer:
Question 2. Match the vector operation property with its statement.
(i) Commutativity of Addition
(ii) Associativity of Addition
(iii) Identity for Addition
(iv) Distributivity of Scalar Multiplication over Vector Addition
(v) Associativity of Scalar Multiplication
(a) $k_1(k_2\vec{a}) = (k_1k_2)\vec{a}$
(b) $\vec{a} + \vec{b} = \vec{b} + \vec{a}$
(c) $\vec{a} + \vec{0} = \vec{a}$
(d) $k(\vec{a} + \vec{b}) = k\vec{a} + k\vec{b}$
(e) $(\vec{a} + \vec{b}) + \vec{c} = \vec{a} + (\vec{b} + \vec{c})$
Answer:
Question 3. Match the physical quantity with its classification (Scalar or Vector).
(i) Speed
(ii) Acceleration
(iii) Distance
(iv) Force
(v) Mass
(a) Vector
(b) Scalar
Answer:
Question 4. Match the vector notation with its meaning.
(i) $\vec{a}$
(ii) $|\vec{a}|$
(iii) $-\vec{a}$
(iv) $\hat{a}$
(v) $\vec{AB}$
(a) Magnitude of vector $\vec{a}$.
(b) A vector quantity.
(c) A vector from point A to point B.
(d) A unit vector in the direction of $\vec{a}$.
(e) A vector with the same magnitude as $\vec{a}$ but opposite direction.
Answer:
Question 5. Match the result of the given vector operations.
(i) $\vec{v} + \vec{0}$
(ii) $\vec{v} - \vec{v}$
(iii) $k \cdot \vec{0}$ (scalar $k$)
(iv) $1 \cdot \vec{v}$
(v) $0 \cdot \vec{v}$
(a) $\vec{0}$
(b) $\vec{v}$
Answer:
Components of a Vector and Linear Combinations
Question 1. Match the vector described with its component representation.
(i) Position vector of (2, -1, 3)
(ii) Vector from (1, 2) to (4, 6)
(iii) Unit vector along positive z-axis
(iv) Vector with magnitude 5 along positive x-axis
(v) Zero vector in 3D
(a) $5\hat{i}$
(b) $3\hat{i} + 4\hat{j}$
(c) $2\hat{i} - \hat{j} + 3\hat{k}$
(d) $\vec{0}$
(e) $\hat{k}$
Answer:
Question 2. Match the vector property with the condition on its components.
(i) $\vec{v} = x\hat{i} + y\hat{j}$ is a unit vector
(ii) Vectors $\vec{a}=(a_1,a_2,a_3)$ and $\vec{b}=(b_1,b_2,b_3)$ are collinear
(iii) Position vector of origin
(iv) Magnitude of $\vec{v} = x\hat{i} + y\hat{j} + z\hat{k}$
(v) Collinearity of points A, B, C with position vectors $\vec{a}, \vec{b}, \vec{c}$
(a) $\vec{0}$
(b) $\vec{AB} = k \vec{AC}$ for some scalar $k$
(c) $\frac{a_1}{b_1} = \frac{a_2}{b_2} = \frac{a_3}{b_3}$ (if denominators are non-zero)
(d) $x^2 + y^2 = 1$
(e) $\sqrt{x^2 + y^2 + z^2}$
Answer:
Question 3. Match the linear combination concept with its description.
(i) Linear Combination
(ii) Linearly Dependent Vectors
(iii) Basis Vectors in 2D
(iv) Coplanar Vectors (non-zero)
(v) Standard Basis in 3D
(a) $\hat{i}, \hat{j}, \hat{k}$
(b) One vector is a linear combination of the others.
(c) An expression of the form $c_1\vec{v}_1 + c_2\vec{v}_2 + \dots + c_n\vec{v}_n$
(d) Any three vectors whose scalar triple product is zero.
(e) Two non-zero, non-collinear vectors in a plane.
Answer:
Question 4. Match the vector addition/subtraction in components.
(i) $(a_1\hat{i} + a_2\hat{j}) + (b_1\hat{i} + b_2\hat{j})$
(ii) $(a_1\hat{i} + a_2\hat{j} + a_3\hat{k}) - (b_1\hat{i} + b_2\hat{j} + b_3\hat{k})$
(iii) $k(a_1\hat{i} + a_2\hat{j} + a_3\hat{k})$
(iv) $\frac{1}{|\vec{v}|}\vec{v}$ where $\vec{v} = x\hat{i} + y\hat{j} + z\hat{k}$
(v) Vector joining P$(x_1, y_1)$ to Q$(x_2, y_2)$
(a) $(x_2-x_1)\hat{i} + (y_2-y_1)\hat{j}$
(b) $(a_1+b_1)\hat{i} + (a_2+b_2)\hat{j}$
(c) $\frac{x\hat{i} + y\hat{j} + z\hat{k}}{\sqrt{x^2+y^2+z^2}}$
(d) $ka_1\hat{i} + ka_2\hat{j} + ka_3\hat{k}$
(e) $(a_1-b_1)\hat{i} + (a_2-b_2)\hat{j} + (a_3-b_3)\hat{k}$
Answer:
Question 5. Match the description of a vector with its component property.
(i) Vector parallel to y-axis
(ii) Vector in xz-plane
(iii) Vector with zero magnitude
(iv) Vector $\vec{v}=v_x\hat{i} + v_y\hat{j}$ scaled by 2
(v) Vector $\vec{AB}$ where A and B have same x-coordinate
(a) $v_x=0, v_z=0$
(b) $v_x=0$ for $\vec{AB}$
(c) $v_y=0$
(d) $v_x=0, v_y=0, v_z=0$
(e) $2v_x\hat{i} + 2v_y\hat{j}$
Answer:
Scalar (Dot) Product of Vectors
Question 1. Match the dot product expression with its value or property.
(i) $\hat{i} \cdot \hat{j}$
(ii) $\hat{k} \cdot \hat{k}$
(iii) $\vec{a} \cdot \vec{b}$ if $\vec{a} \perp \vec{b}$
(iv) $\vec{a} \cdot \vec{0}$
(v) $\vec{a} \cdot \vec{a}$
(a) $|\vec{a}|^2$
(b) 0
(c) 1
Answer:
Question 2. Match the formula or concept with its application/meaning in dot product.
(i) Work Done
(ii) Angle between vectors $\vec{a}, \vec{b}$
(iii) Scalar projection of $\vec{a}$ on $\vec{b}$
(iv) Vector projection of $\vec{a}$ on $\vec{b}$
(v) $\vec{a} \cdot \vec{b}$ in components
(a) $\frac{\vec{a} \cdot \vec{b}}{|\vec{b}|}$
(b) $\vec{F} \cdot \vec{d}$
(c) $a_1b_1 + a_2b_2 + a_3b_3$
(d) $\cos^{-1}\left(\frac{\vec{a} \cdot \vec{b}}{|\vec{a}||\vec{b}|}\right)$
(e) $(\frac{\vec{a} \cdot \vec{b}}{|\vec{b}|^2})\vec{b}$
Answer:
Question 3. Match the dot product value with the angle between non-zero vectors.
(i) $\vec{a} \cdot \vec{b} > 0$
(ii) $\vec{a} \cdot \vec{b} < 0$
(iii) $\vec{a} \cdot \vec{b} = 0$
(iv) $\vec{a} \cdot \vec{b} = |\vec{a}||\vec{b}|$
(v) $\vec{a} \cdot \vec{b} = -|\vec{a}||\vec{b}|$
(a) Angle is $180^\circ$ (parallel in opposite direction).
(b) Angle is $90^\circ$ (perpendicular).
(c) Angle is acute.
(d) Angle is $0^\circ$ (parallel in same direction).
(e) Angle is obtuse.
Answer:
Question 4. Match the property of dot product with its name.
(i) $\vec{a} \cdot \vec{b} = \vec{b} \cdot \vec{a}$
(ii) $\vec{a} \cdot (\vec{b} + \vec{c}) = \vec{a} \cdot \vec{b} + \vec{a} \cdot \vec{c}$
(iii) $(k\vec{a}) \cdot \vec{b} = k(\vec{a} \cdot \vec{b})$
(iv) $\vec{a} \cdot \vec{a} \ge 0$
(v) $\vec{a} \cdot \vec{0} = 0$
(a) Property of non-negativity
(b) Property of zero vector
(c) Commutativity
(d) Associativity with scalar
(e) Distributivity
Answer:
Question 5. Match the vectors with their dot product.
(i) $\hat{i} + \hat{j}$ and $\hat{i} - \hat{j}$
(ii) $2\hat{i}$ and $3\hat{i}$
(iii) $\hat{i} + 2\hat{j} + 3\hat{k}$ and $2\hat{i} + \hat{j} + \hat{k}$
(iv) $\hat{i} + \hat{j} + \hat{k}$ and $\hat{i} + \hat{j} + \hat{k}$
(v) $2\hat{i} + \hat{j}$ and $\hat{i} - 2\hat{j}$
(a) 6
(b) 0
(c) 3
(d) 5
Answer:
Vector (Cross) Product of Vectors
Question 1. Match the cross product expression with its result or property.
(i) $\hat{i} \times \hat{j}$
(ii) $\hat{k} \times \hat{k}$
(iii) $\vec{a} \times \vec{b}$ if $\vec{a} \parallel \vec{b}$
(iv) $\vec{a} \times \vec{0}$
(v) $\vec{a} \times \vec{a}$
(a) $\vec{0}$
(b) $\hat{k}$
Answer:
Question 2. Match the formula or concept with its application/meaning in cross product.
(i) Area of parallelogram with sides $\vec{a}, \vec{b}$
(ii) Area of triangle with sides $\vec{a}, \vec{b}$
(iii) A vector perpendicular to $\vec{a}$ and $\vec{b}$
(iv) Torque $\vec{\tau}$ by force $\vec{F}$ at position $\vec{r}$
(v) Unit vector perpendicular to $\vec{a}$ and $\vec{b}$
(a) $\vec{a} \times \vec{b}$
(b) $\frac{1}{2}|\vec{a} \times \vec{b}|$
(c) $|\vec{a} \times \vec{b}|$
(d) $\vec{r} \times \vec{F}$
(e) $\frac{\vec{a} \times \vec{b}}{|\vec{a} \times \vec{b}|}$
Answer:
Question 3. Match the cross product value with the angle between non-zero vectors.
(i) $|\vec{a} \times \vec{b}| > 0$
(ii) $|\vec{a} \times \vec{b}| = 0$
(iii) $|\vec{a} \times \vec{b}| = |\vec{a}||\vec{b}|$
(iv) $\vec{a} \times \vec{b}$ direction is along $\hat{n}$
(v) $\vec{b} \times \vec{a}$ direction is along $-\hat{n}$
(a) Vectors are parallel/collinear.
(b) Right-hand rule.
(c) Vectors are perpendicular.
(d) Vectors are not parallel/collinear.
(e) Anti-commutativity.
Answer:
Question 4. Match the property of cross product with its name or statement.
(i) $\vec{a} \times \vec{b} = -\vec{b} \times \vec{a}$
(ii) $\vec{a} \times (\vec{b} + \vec{c}) = \vec{a} \times \vec{b} + \vec{a} \times \vec{c}$
(iii) $(k\vec{a}) \times \vec{b} = k(\vec{a} \times \vec{b})$
(iv) $\vec{a} \times \vec{a} = \vec{0}$
(v) $\vec{a} \times (\vec{b} \times \vec{c})$
(a) Vector triple product.
(b) Property of parallel vectors.
(c) Distributivity over vector addition.
(d) Associativity with scalar.
(e) Anti-commutativity.
Answer:
Question 5. Match the pairs of vectors with their cross product magnitude.
(i) $\hat{i} + \hat{j}$ and $\hat{i} - \hat{j}$
(ii) $2\hat{i}$ and $3\hat{i}$
(iii) $\hat{i} + \hat{j}$ and $\hat{j}$
(iv) $2\hat{i}$ and $3\hat{j}$
(v) $\hat{i}$ and $\hat{j}$
(a) 0
(b) 1
(c) 2
(d) 6
Answer:
Scalar Triple Product
Question 1. Match the scalar triple product expression with its calculation method or property.
(i) $[\vec{a}, \vec{b}, \vec{c}]$
(ii) $[\vec{a}, \vec{b}, \vec{c}]$ using components
(iii) $[\vec{a}, \vec{a}, \vec{c}]$
(iv) $[\hat{i}, \hat{j}, \hat{k}]$
(v) $[\vec{a}, \vec{b}, \vec{c}]$ vs $[\vec{b}, \vec{c}, \vec{a}]$
(a) Value is 0.
(b) $\vec{a} \cdot (\vec{b} \times \vec{c})$
(c) Value is 1.
(d) Value is the same.
(e) Determinant $\begin{vmatrix} a_1 & a_2 & a_3 \\ b_1 & b_2 & b_3 \\ c_1 & c_2 & c_3 \end{vmatrix}$.
Answer:
Question 2. Match the scalar triple product value or condition with its geometric interpretation or implication.
(i) $|[\vec{a}, \vec{b}, \vec{c}]|$
(ii) $\frac{1}{6}|[\vec{a}, \vec{b}, \vec{c}]|$
(iii) $[\vec{a}, \vec{b}, \vec{c}] = 0$
(iv) $[\vec{a}, \vec{b}, \vec{c}] \neq 0$
(v) $[\vec{a}, \vec{b}, \vec{c}] > 0$
(a) Vectors are coplanar.
(b) Volume of parallelepiped.
(c) Vectors are non-coplanar.
(d) Vectors form a right-handed system.
(e) Volume of tetrahedron.
Answer:
Question 3. Match the property of scalar triple product with its statement.
(i) Permutation
(ii) Identical Vectors
(iii) Scalar Multiplication
(iv) Distributivity
(v) Dot and Cross Interchange
(a) $[\vec{a}+\vec{d}, \vec{b}, \vec{c}] = [\vec{a}, \vec{b}, \vec{c}] + [\vec{d}, \vec{b}, \vec{c}]$
(b) $\vec{a} \cdot (\vec{b} \times \vec{c}) = (\vec{a} \times \vec{b}) \cdot \vec{c}$
(c) $[\vec{a}, \vec{a}, \vec{b}] = 0$
(d) $[k\vec{a}, \vec{b}, \vec{c}] = k[\vec{a}, \vec{b}, \vec{c}]$
(e) $[\vec{a}, \vec{b}, \vec{c}] = [\vec{b}, \vec{c}, \vec{a}]$
Answer:
Question 4. Match the sets of vectors with their scalar triple product value (absolute value or condition for zero).
(i) $\{\hat{i}, \hat{j}, \hat{k}\}$
(ii) $\{\hat{i} + \hat{j}, \hat{j} + \hat{k}, \hat{i} + \hat{k}\}$
(iii) $\{\hat{i} - \hat{j}, \hat{j} - \hat{k}, \hat{k} - \hat{i}\}$
(iv) $\{2\hat{i}, 3\hat{j}, 4\hat{k}\}$
(v) $\{\vec{a}, \vec{b}, \vec{a}+\vec{b}\}$
(a) 24
(b) 2
(c) 0 (always coplanar)
(d) 0 (always coplanar)
(e) 1
Answer:
Question 5. Match the concept related to coplanarity with the scalar triple product condition.
(i) Condition for coplanarity of $\vec{a}, \vec{b}, \vec{c}$
(ii) Volume of parallelepiped is zero
(iii) Vectors are linearly dependent (non-trivial linear combination is zero)
(iv) Points A, B, C, D are coplanar
(v) $\vec{a} \cdot (\vec{b} \times \vec{c})$
(a) Same as $[\vec{a}, \vec{b}, \vec{c}]$
(b) $[\vec{a}, \vec{b}, \vec{c}] = 0$
(c) $[\vec{AB}, \vec{AC}, \vec{AD}] = 0$
(d) $[\vec{a}, \vec{b}, \vec{c}] = 0$
(e) $[\vec{a}, \vec{b}, \vec{c}] = 0$
Answer:
Section Formula in Vector Algebra
Question 1. Match the type of section with its vector formula for point R dividing AB with position vectors $\vec{a}, \vec{b}$ in ratio $m:n$.
(i) Internal Division (R on AB)
(ii) External Division (R on AB extended, beyond B, $m>n$)
(iii) External Division (R on AB extended, beyond A, $m (iv) Midpoint of AB (v) Point dividing AB in ratio 1:2 internally
(a) $\frac{\vec{a} + 2\vec{b}}{3}$
(b) $\frac{m\vec{b} - n\vec{a}}{m-n}$
(c) $\frac{n\vec{a} + m\vec{b}}{m+n}$
(d) $\frac{m\vec{b} - n\vec{a}}{m-n}$ (where $m-n$ is negative)
(e) $\frac{\vec{a} + \vec{b}}{2}$
Answer:
Question 2. Match the special point of a geometric figure with the formula for its position vector.
(i) Midpoint of a line segment
(ii) Centroid of a triangle
(iii) Centroid of a tetrahedron
(iv) Point dividing AB internally 1:0
(v) Point dividing AB internally 0:1
(a) $\vec{b}$
(b) $\frac{\vec{a} + \vec{b}}{2}$
(c) $\frac{\vec{a} + \vec{b} + \vec{c}}{3}$
(d) $\frac{\vec{a} + \vec{b} + \vec{c} + \vec{d}}{4}$
(e) $\vec{a}$
Answer:
Question 3. Match the description of point R on line AB with position vectors $\vec{a}, \vec{b}$.
(i) $\vec{r} = \frac{\vec{a} + \vec{b}}{2}$
(ii) $\vec{r} = \frac{2\vec{b} + \vec{a}}{3}$
(iii) $\vec{r} = 2\vec{b} - \vec{a}$
(iv) $\vec{r} = \vec{a} + 2(\vec{b}-\vec{a})$
(v) $\vec{r} = \vec{a} - (\vec{b}-\vec{a})$
(a) R divides AB internally in ratio 1:2.
(b) R divides AB externally in ratio 2:1.
(c) R is the midpoint of AB.
(d) R divides AB externally in ratio 1:2 (i.e., extends beyond A).
(e) R divides AB internally in ratio 2:1.
Answer:
Question 4. Match the points with their position vectors related to a triangle with vertices A, B, C (pos vectors $\vec{a}, \vec{b}, \vec{c}$).
(i) Midpoint of BC
(ii) Centroid of triangle ABC
(iii) Point dividing median from A in ratio 2:1
(iv) Point dividing AB internally in ratio 1:1
(v) Point dividing AC internally in ratio 1:1
(a) $\frac{\vec{a} + \vec{c}}{2}$
(b) $\frac{\vec{a} + \vec{b} + \vec{c}}{3}$
(c) $\frac{\vec{b} + \vec{c}}{2}$
(d) Same as (ii)
(e) $\frac{\vec{a} + \vec{b}}{2}$
Answer:
Question 5. If points P, Q, R are collinear with position vectors $\vec{p}, \vec{q}, \vec{r}$ and R divides PQ internally in ratio $m:n$, match the ratios.
(i) R divides PQ in ratio $m:n$ internally
(ii) R divides QP in ratio $n:m$ internally
(iii) R divides PQ in ratio $m:n$ externally
(iv) R divides QP in ratio $n:m$ externally
(v) R is the midpoint of PQ
(a) $1:1$
(b) $\vec{r} = \frac{n\vec{p} + m\vec{q}}{m+n}$
(c) $\vec{r} = \frac{n\vec{q} + m\vec{p}}{n+m}$
(d) $\vec{r} = \frac{m\vec{q} - n\vec{p}}{m-n}$
(e) $\vec{r} = \frac{n\vec{p} - m\vec{q}}{n-m}$
Answer:
Three Dimensional Geometry: Introduction and Lines
Question 1. Match the geometric element/concept in 3D with its basic property or representation.
(i) x-axis
(ii) xy-plane
(iii) Point (a,b,c)
(iv) Direction Cosines $(\ell,m,n)$
(v) Direction Ratios $(a,b,c)$
(a) $\ell^2 + m^2 + n^2 = 1$
(b) Equation $z=0$
(c) Proportional to direction cosines
(d) Equation $y=0, z=0$
(e) Has position vector $a\hat{i} + b\hat{j} + c\hat{k}$
Answer:
Question 2. Match the form of a line's equation with its structure.
(i) Vector form (point and parallel vector)
(ii) Vector form (two points)
(iii) Cartesian form (point and direction ratios)
(iv) Cartesian form (two points)
(v) Parametric Cartesian form
(a) $\frac{x-x_1}{x_2-x_1} = \frac{y-y_1}{y_2-y_1} = \frac{z-z_1}{z_2-z_1}$
(b) $x=x_1+\lambda a, y=y_1+\lambda b, z=z_1+\lambda c$
(c) $\vec{r} = (1-\lambda)\vec{a} + \lambda\vec{b}$
(d) $\frac{x-x_1}{a} = \frac{y-y_1}{b} = \frac{z-z_1}{c}$
(e) $\vec{r} = \vec{a} + \lambda \vec{b}$
Answer:
Question 3. Match the distance calculation with the points involved.
(i) Distance between $(x_1, y_1, z_1)$ and origin
(ii) Distance between $(x_1, y_1, z_1)$ and $(x_2, y_2, z_2)$
(iii) Distance between origin and point $\vec{r} = x\hat{i} + y\hat{j} + z\hat{k}$
(iv) Magnitude of vector $\vec{PQ}$
(v) Distance between $(a,b,c)$ and the xy-plane
(a) $|c|$
(b) $\sqrt{x_1^2 + y_1^2 + z_1^2}$
(c) $\sqrt{(x_2-x_1)^2 + (y_2-y_1)^2 + (z_2-z_1)^2}$
(d) Same as (ii)
(e) $\sqrt{x^1+y^1+z^1}$
Answer:
Question 4. Match the line equation parameter/component with its role.
(i) $\vec{a}$ in $\vec{r} = \vec{a} + \lambda \vec{b}$
(ii) $\vec{b}$ in $\vec{r} = \vec{a} + \lambda \vec{b}$
(iii) $\lambda$ in $\vec{r} = \vec{a} + \lambda \vec{b}$
(iv) $(a,b,c)$ in $\frac{x-x_1}{a} = \frac{y-y_1}{b} = \frac{z-z_1}{c}$
(v) $(x_1,y_1,z_1)$ in $\frac{x-x_1}{a} = \frac{y-y_1}{b} = \frac{z-z_1}{c}$
(a) A point on the line.
(b) Direction vector.
(c) Scalar parameter.
(d) Direction ratios.
Answer:
Question 5. Match the properties of direction cosines and ratios.
(i) Direction cosines of a line
(ii) Direction ratios of a line
(iii) Sum of squares of direction cosines
(iv) Angles $\alpha, \beta, \gamma$ with axes
(v) Line makes equal angles with axes
(a) Can be any three numbers proportional to direction cosines.
(b) Value is 1.
(c) Cosines of these angles are direction cosines.
(d) Direction cosines are $(\frac{1}{\sqrt{3}}, \frac{1}{\sqrt{3}}, \frac{1}{\sqrt{3}})$ or $(-\frac{1}{\sqrt{3}}, -\frac{1}{\sqrt{3}}, -\frac{1}{\sqrt{3}})$.
(e) Cosines of angles made with coordinate axes.
Answer:
Three Dimensional Geometry: Planes
Question 1. Match the form of a plane's equation with its structure.
(i) Vector form (Normal form)
(ii) Vector form (Point-Normal form)
(iii) Cartesian form (General form)
(iv) Cartesian form (Intercept form)
(v) Cartesian form (Normal form)
(a) $Ax + By + Cz + D = 0$
(b) $lx + my + nz = p$ (where $\ell,m,n$ are direction cosines of normal, $p$ is distance from origin)
(c) $\vec{r} \cdot \hat{n} = d$
(d) $\frac{x}{a} + \frac{y}{b} + \frac{z}{c} = 1$
(e) $(\vec{r} - \vec{a}) \cdot \vec{n} = 0$
Answer:
Question 2. Match the equation of a plane with its property or related vector.
(i) $2x - y + 3z = 5$
(ii) $\vec{r} \cdot (4\hat{i} + \hat{j} - 2\hat{k}) = 10$
(iii) Plane passing through origin
(iv) Plane parallel to xy-plane
(v) Normal vector to plane $Ax+By+Cz+D=0$
(a) $Ax+By+Cz=0$
(b) Normal vector is $2\hat{i} - \hat{j} + 3\hat{k}$
(c) Vector $A\hat{i} + B\hat{j} + C\hat{k}$
(d) Normal vector is $4\hat{i} + \hat{j} - 2\hat{k}$
(e) Equation form $z=c$ or $Az+D=0$ (with A=0, B=0)
Answer:
Question 3. Match the definition of a plane with the information required to define it.
(i) Plane through 3 points
(ii) Plane through a point perpendicular to a vector
(iii) Plane through origin and perpendicular to a vector
(iv) Plane through a point and containing two non-collinear vectors
(v) Plane defined by intercepts
(a) A point and a normal vector.
(b) Intercepts a, b, c on axes (non-zero).
(c) Three non-collinear points.
(d) Origin and a normal vector.
(e) A point and two non-collinear vectors parallel to the plane.
Answer:
Question 4. Match the plane equation with a point that lies on it.
(i) $x+y+z=3$
(ii) $2x-y+z=0$
(iii) $x=5$
(iv) $z=0$
(v) $\vec{r} \cdot (\hat{i} + \hat{j}) = 2$
(a) (5, 1, 2)
(b) (1, 1, 1)
(c) (0, 0, 0)
(d) (1, 1, 0)
(e) (1, 2, 0)
Answer:
Question 5. Match the Cartesian equation coefficients with the vector normal form $\vec{r} \cdot \hat{n} = d$. Assume $Ax+By+Cz+D=0$ is the Cartesian form.
(i) Components of normal vector $\vec{n}$
(ii) Unit normal vector $\hat{n}$
(iii) Distance from origin $d$ (when $D \neq 0$)
(iv) Sign of $d$ (distance from origin)
(v) Constant term $D$
(a) $\frac{|-D|}{\sqrt{A^2+B^2+C^2}}$
(b) $(A, B, C)$
(c) $\frac{A\hat{i} + B\hat{j} + C\hat{k}}{\sqrt{A^2+B^2+C^2}}$ if $D<0$ or $\frac{-A\hat{i} - B\hat{j} - C\hat{k}}{\sqrt{A^2+B^2+C^2}}$ if $D>0$.
(d) Related to distance and direction of normal.
(e) Must be positive in the normal form $lx+my+nz=p$ where $p>0$.
Answer:
Three Dimensional Geometry: Angles
Question 1. Match the pair of geometric objects with the vectors whose angle determines their angle.
(i) Two lines
(ii) Two planes
(iii) A line and a plane
(iv) A line and a coordinate axis
(v) A plane and a coordinate plane
(a) Normal vector of plane and normal vector of coordinate plane.
(b) Direction vector of line and direction vector of coordinate axis.
(c) Direction vectors of the lines.
(d) Normal vectors of the planes.
(e) Direction vector of line and normal vector of plane (complementary angle).
Answer:
Question 2. Match the condition for parallelism or perpendicularity with the type of geometric objects.
(i) Two lines $\vec{b}_1 \cdot \vec{b}_2 = 0$
(ii) Two lines $\vec{b}_1 = k\vec{b}_2$
(iii) Two planes $\vec{n}_1 \cdot \vec{n}_2 = 0$
(iv) Two planes $\vec{n}_1 = k\vec{n}_2$
(v) Line $\vec{b}$ and Plane $\vec{n}$ with $\vec{b} \cdot \vec{n} = 0$
(a) Planes are parallel (or coincident).
(b) Lines are perpendicular.
(c) Line is parallel to the plane (or lies in the plane).
(d) Planes are perpendicular.
(e) Lines are parallel (or collinear).
Answer:
Question 3. Match the trigonometric function of the angle with the formula.
(i) Cosine of angle between two lines (direction vectors $\vec{b}_1, \vec{b}_2$)
(ii) Cosine of angle between two planes (normal vectors $\vec{n}_1, \vec{n}_2$)
(iii) Sine of angle between a line $\vec{b}$ and a plane $\vec{n}$
(iv) Cosine of angle between a line $\vec{b}$ and the normal $\vec{n}$
(v) Sine of angle between a line $\vec{b}$ and the normal $\vec{n}$
(a) $\frac{|\vec{b} \cdot \vec{n}|}{|\vec{b}||\vec{n}|}$
(b) $\frac{|\vec{b} \cdot \vec{n}|}{|\vec{b}||\vec{n}|}$
(c) $\frac{|\vec{b} \cdot \vec{n}|}{|\vec{b}||\vec{n}|}$
(d) $\frac{|\vec{n}_1 \cdot \vec{n}_2|}{|\vec{n}_1||\vec{n}_2|}$
(e) $\frac{|\vec{b}_1 \cdot \vec{b}_2|}{|\vec{b}_1||\vec{b}_2|}$
Answer:
Question 4. Match the pair of objects with their angle property based on direction ratios/normal vectors.
(i) Lines $(a_1, b_1, c_1)$ and $(a_2, b_2, c_2)$ are parallel
(ii) Lines $(a_1, b_1, c_1)$ and $(a_2, b_2, c_2)$ are perpendicular
(iii) Planes $(A_1, B_1, C_1)$ and $(A_2, B_2, C_2)$ are parallel
(iv) Planes $(A_1, B_1, C_1)$ and $(A_2, B_2, C_2)$ are perpendicular
(v) Line $(a, b, c)$ and Plane $(A, B, C)$ are perpendicular
(a) $A_1A_2 + B_1B_2 + C_1C_2 = 0$
(b) $\frac{a_1}{a_2} = \frac{b_1}{b_2} = \frac{c_1}{c_2}$
(c) $aA + bB + cC = 0$ (Line parallel to plane)
(d) $a_1a_2 + b_1b_2 + c_1c_2 = 0$
(e) $\frac{A_1}{A_2} = \frac{B_1}{B_2} = \frac{C_1}{C_2}$
Answer:
Question 5. Match the specific pair of objects with the formula for the cosine of the angle between them.
(i) Line $\frac{x-x_1}{a_1}=\frac{y-y_1}{b_1}=\frac{z-z_1}{c_1}$ and Line $\frac{x-x_2}{a_2}=\frac{y-y_2}{b_2}=\frac{z-z_2}{c_2}$
(ii) Plane $A_1x+B_1y+C_1z+D_1=0$ and Plane $A_2x+B_2y+C_2z+D_2=0$
(iii) Line $\frac{x-x_1}{a}=\frac{y-y_1}{b}=\frac{z-z_1}{c}$ and Plane $Ax+By+Cz+D=0$ (use sine for line-plane angle)
(iv) x-axis and y-axis
(v) xy-plane and xz-plane
(a) Formula involves $\frac{|aA+bB+cC|}{\sqrt{a^2+b^2+c^2}\sqrt{A^2+B^2+C^2}}$ (This is cos of angle between line and normal)
(b) $\frac{|A_1A_2+B_1B_2+C_1C_2|}{\sqrt{A_1^2+B_1^2+C_1^2}\sqrt{A_2^2+B_2^2+C_2^2}}$
(c) 0
(d) $\frac{|a_1a_2+b_1b_2+c_1c_2|}{\sqrt{a_1^2+b_1^2+c_1^2}\sqrt{a_2^2+b_2^2+c_2^2}}$
(e) 0
Answer:
Three Dimensional Geometry: Distances
Question 1. Match the pair of objects with the type of distance calculation required.
(i) Point to Plane
(ii) Point to Origin
(iii) Two Points
(iv) Two Parallel Planes
(v) Two Skew Lines
(a) Distance formula $\sqrt{\Delta x^2 + \Delta y^2 + \Delta z^2}$
(b) $\frac{|Ax_1 + By_1 + Cz_1 + D|}{\sqrt{A^2+B^2+C^2}}$
(c) $\frac{|D_2 - D_1|}{\sqrt{A^2+B^2+C^2}}$
(d) $\frac{|(\vec{a}_2 - \vec{a}_1) \cdot (\vec{b}_1 \times \vec{b}_2)|}{|\vec{b}_1 \times \vec{b}_2|}$
(e) $\sqrt{x^1+y^1+z^1}$
Answer:
Question 2. Match the distance formula with the specific case of lines.
(i) Shortest distance between two skew lines $\vec{r} = \vec{a}_1 + \lambda \vec{b}_1, \vec{r} = \vec{a}_2 + \mu \vec{b}_2$
(ii) Shortest distance between two parallel lines $\vec{r} = \vec{a}_1 + \lambda \vec{b}, \vec{r} = \vec{a}_2 + \mu \vec{b}$
(iii) Shortest distance between two intersecting lines
(iv) Shortest distance between a point P and a line L (point A on L, direction $\vec{b}$)
(v) Shortest distance between a point P and itself
(a) 0
(b) $\frac{|(\vec{a}_2 - \vec{a}_1) \times \vec{b}|}{|\vec{b}|}$
(c) 0
(d) $\frac{|(\vec{a}_2 - \vec{a}_1) \cdot (\vec{b}_1 \times \vec{b}_2)|}{|\vec{b}_1 \times \vec{b}_2|}$
(e) $\frac{|\vec{AP} \times \vec{b}|}{|\vec{b}|}$
Answer:
Question 3. Match the distance from a point to a plane with the result.
(i) Distance of (1,1,1) from $x+y+z=3$
(ii) Distance of (1,2,3) from $z=0$
(iii) Distance of origin from $x=5$
(iv) Distance of origin from $2x+3y+6z=7$
(v) Distance of (1,1,1) from $x=0$
(a) 3
(b) 1
(c) 0
(d) 5
(e) $\frac{7}{\sqrt{2^2+3^2+6^2}} = \frac{7}{\sqrt{4+9+36}} = \frac{7}{\sqrt{49}} = 1$
Answer:
Question 4. Match the property of lines based on their shortest distance.
(i) Shortest distance is 0
(ii) Shortest distance is non-zero
(iii) Lines are coplanar
(iv) Lines are intersecting
(v) Lines are parallel and distinct
(a) Shortest distance formula for parallel lines is used.
(b) The lines are skew.
(c) The lines are intersecting or coincident.
(d) Shortest distance is 0.
(e) Shortest distance formula for skew lines is not applicable (denominator $\vec{b}_1 \times \vec{b}_2 = \vec{0}$).
Answer:
Question 5. Match the distance between planes with the condition or formula.
(i) Distance between two parallel planes
(ii) Distance between two intersecting planes
(iii) Distance between coincident planes
(iv) Distance between plane $Ax+By+Cz+D=0$ and origin
(v) Distance between planes $x+y+z=1$ and $2x+2y+2z=2$
(a) 0
(b) $\frac{|D|}{\sqrt{A^2+B^2+C^2}}$
(c) Formula $\frac{|D_2-D_1|}{\sqrt{A^2+B^2+C^2}}$ applies.
(d) 0
(e) 0 (Planes are the same after simplification)
Answer: