# MCQ Questions for Class 11 Maths Chapter 10 Straight Lines with Answers

## MCQ Questions for Class 11 Maths Chapter 10 Straight Lines with Answers

Question 1.
The locus of a point, whose abscissa and ordinate are always equal is
(a) x + y + 1 = 0
(b) x – y = 0
(c) x + y = 1

Answer: (b) x – y = 0

Question 2.
The equation of straight line passing through the point (1, 2) and parallel to the line y = 3x + 1 is
(a) y + 2 = x + 1
(b) y + 2 = 3 × (x + 1)
(c) y – 2 = 3 × (x – 1)
(d) y – 2 = x – 1

Answer: (c) y – 2 = 3 × (x – 1)

Question 3.
What can be said regarding if a line if its slope is negative
(a) θ is an acute angle
(b) θ is an obtuse angle
(c) Either the line is x-axis or it is parallel to the x-axis.

Answer: (b) θ is an obtuse angle
Hint:
Let θ be the angle of inclination of the given line with the positive direction of x-axis in the anticlockwise sense.
Then its slope is given by m = tan θ
Given, slope is positive
⇒ tan θ < 0
⇒ θ lies between 0 and 180 degree
⇒ θ is an obtuse angle

Question 4:
The equation of the line which cuts off equal and positive intercepts from the axes and passes through the point (α, β) is
(a) x + y = α + β
(b) x + y = α
(c) x + y = β

Answer: (a) x + y = α + β
Hint:
Let the equation of the line be x/a + y/b = 1 which cuts off intercepts a and b with
the coordinate axes.
It is given that a = b, therefore the equation of the line is
x/a + y/a = 1
⇒ x + y = a …..1
But it is passes through (α, β)
So, α + β = a
Put this value in equation 1, we get
x + y = α + β

Question 5.
Two lines a1x + b1y + c1 = 0 and a2x + b2y + c2 = 0 are coincedent if
(a) a1/a2 = b1/b2 ≠ c1/c2
(b) a1/a2 ≠ b1/b2 = c1/c2
(c) a1/a2 ≠ b1/b2 ≠ c1/c2
(d) a1/a2 = b1/b2 = c1/c2Answer

Answer: (d) a1/a2 = b1/b2 = c1/c2
Hint:
Two lines a1x + b1y + c1 = 0 and a2x + b2y + c2 = 0 are coincedent if
a1/a2 = b1/b2 = c1/c2

Question 6:
The equation of the line passing through the point (2, 3) with slope 2 is
(a) 2x + y – 1 = 0
(b) 2x – y + 1 = 0
(c) 2x – y – 1 = 0
(d) 2x + y + 1 = 0Answer

Answer: (c) 2x – y – 1 = 0
Hint:
Given, the point (2, 3) and slope of the line is 2
By, slope-intercept formula,
y – 3 = 2(x – 2)
⇒ y – 3 = 2x – 4
⇒ 2x – 4 – y + 3 = 0
⇒ 2x – y – 1 = 0

Question 7.
The slope of the line ax + by + c = 0 is
(a) a/b
(b) -a/b
(c) -c/b

Hint:
Give, equation of line is ax + by + c = 0
⇒ by = -ax – c
⇒ y = (-a/b)x – c/b
It is in the form of y = mx + c
Now, slope m = -a/b

Question 8.
Equation of the line passing through (0, 0) and slope m is
(a) y = mx + c
(b) x = my + c
(c) y = mx

Hint:
Equation of the line passing through (x1, y1) and slope m is
(y – y1) = m(x – x1)
Now, required line is
(y – 0 ) = m(x – 0)
⇒ y = mx

Question 9.
The angle between the lines x – 2y = 4 and y – 2x = 5 is
(a) tan-1 (1/4)
(b) tan-1 (3/5)
(c) tan-1 (5/4)
(d) tan-1 (2/3)

Question 10.
Two lines a1x + b1y + c1 = 0 and a2x + b2y + c2 = 0 are parallel if
(a) a1/a2 = b1/b2 ≠ c1/c2
(b) a1/a2 ≠ b1/b2 = c1/c2
(c) a1/a2 ≠ b1/b2 ≠ c1/c2
(d) a1/a2 = b1/b2 = c1/c2

Answer: (a) a1/a2 = b1/b2 ≠ c1/c2

Question 11.
The locus of a point, whose abscissa and ordinate are always equal is
(a) x + y + 1 = 0
(b) x – y = 0
(c) x + y = 1

Answer: (b) x – y = 0

Question 12.
In a ΔABC, if A is the point (1, 2) and equations of the median through B and C are respectively x + y = 5 and x = 4, then B is
(a) (1, 4)
(b) (7, – 2)
(c) none of these
(d) (4, 1)

Question 13.
The length of the perpendicular from the origin to a line is 7 and the line makes an angle of 150 degrees with the positive direction of the y-axis. Then the equation of line is
(a) x + y = 14
(b) √3y + x = 14
(c) √3x + y = 14
(d) None of these

Answer: (c) √3x + y = 14

Question 14.
If two vertices of a triangle are (3, -2) and (-2, 3) and its orthocenter is (-6, 1) then its third vertex is
(a) (5, 3)
(b) (-5, 3)
(c) (5, -3)
(d) (-5, -3)

Question 15.
The sum of squares of the distances of a moving point from two fixed points (a, 0) and (-a, 0) is equal to 2c² then the equation of its locus is
(a) x² – y² = c² – a²
(b) x² – y² = c² + a²
(c) x² + y² = c² – a²
(d) x² + y² = c² + a²

Answer: (c) x² + y² = c² – a²

Question 16.
The equation of the line through the points (1, 5) and (2, 3) is
(a) 2x – y – 7 = 0
(b) 2x + y + 7 = 0
(c) 2x + y – 7 = 0
(d) x + 2y – 7 = 0Answer

Answer: (c) 2x + y – 7 = 0

Question 17.
What can be said regarding if a line if its slope is zero
(a) θ is an acute angle
(b) θ is an obtuse angle
(c) Either the line is x-axis or it is parallel to the x-axis.
(d) None of these

Answer: (c) Either the line is x-axis or it is parallel to the x-axis.

Question 18.
Two lines are perpendicular if the product of their slopes is
(a) 0
(b) 1
(c) -1
(d) None of these

Question 19.
y-intercept of the line 4x – 3y + 15 = 0 is
(a) -15/4
(b) 15/4
(c) -5
(d) 5