Straight Lines — Class 11 MCQs with Answers
Class 11 CBSE Mathematics · Chapter 10
90 practice questions · 30 Easy · 30 Medium · 30 Hard · Updated
Practise the most important Class 11 CBSE Mathematics questions from Chapter 10, "Straight Lines". You get 9 timed quizzes made from 90 NCERT-based MCQs, with answers and explanations. The questions are split into 30 Easy, 30 Medium and 30 Hard. Warm up on the basics, then move on to the exam-level questions that set top scorers in CBSE & Maharashtra HSC Board exams, JEE Main, MHT-CET and JEE Advanced apart.
To score well in "Straight Lines", focus on fast problem-solving, formula recall and step-by-step working. Each MCQ here is timed and uses exam-style marking (+4 correct, −1 wrong, 0 skipped). This trains you to stay accurate under time pressure, as real papers need. Every question has a short explanation, so a wrong answer becomes a quick lesson. It is the fastest way to fix gaps before a test.
Use this chapter for focused revision. Start with the Easy set to check your basics on Straight Lines, then move to Medium and Hard to practise applying them. Your accuracy, streaks and XP save automatically. This chapter also adds to your overall Class 11 Mathematics mastery score. 14 sample questions are solved in full below, with the answer and a worked explanation. Sign in free to start practising.
Key concepts: Straight Lines (Class 11 Mathematics)
Coordinate geometry turns lines into equations. This chapter defines the slope of a line as the tangent of its inclination, derives the slope-intercept, point-slope, two-point, intercept and normal forms, reduces the general equation Ax + By + C = 0, and finds the angle between two lines and the distance of a point from a line.
- Slope of a line
- m = (y₂ − y₁)/(x₂ − x₁) = tan θ, where θ is the angle the line makes with the positive x-axis; a vertical line has undefined slope.
- Inclination
- The angle θ, with 0° ≤ θ < 180°, measured anticlockwise from the positive x-axis to the line; its tangent gives the slope.
- Parallel and perpendicular
- Parallel lines share equal slopes m₁ = m₂; perpendicular lines satisfy m₁m₂ = −1, so each slope is the negative reciprocal of the other.
- Slope-intercept form
- y = mx + c, where m is the slope and c the y-intercept; the fastest form when the slope and the y-axis crossing are known.
Straight Lines — important questions & MCQs with answers (Class 11 Mathematics)
14 solved questions from this chapter's difficulty levels, each with its answer and explanation. The other 76 are timed and scored when you sign in.
- Q1Easy
Slope of line through (1,2) and (3,8):
A.3✓ CorrectB.2C.4D.6Answer: A. 3
Explanation: Slope = (y₂−y₁)/(x₂−x₁) = (8−2)/(3−1) = 3. Flipping which point is first, or dividing Δx by Δy instead of Δy by Δx, is the usual slip that lands on a wrong value like 2 or 4.
- Q2Easy
Slope-intercept form of a line:
A.y = mx + c✓ CorrectB.ax + by + c = 0C.y = xD.x + y = 0Answer: A. y = mx + c
Explanation: y = mx + c is the slope-intercept form, reading off slope m and y-intercept c directly. The general form ax + by + c = 0 hides both behind extra algebra — rewrite it as y = mx + c to compare.
- Q3Easy
Slope of line 2x + 3y − 6 = 0:
A.−2/3✓ CorrectB.2/3C.3/2D.−3/2Answer: A. −2/3
Explanation: Rewrite in y = mx + c form: 3y = −2x + 6 ⇒ y = −(2/3)x + 2, so slope = −2/3. Reading the coefficient of x directly off the general form without dividing by the y-coefficient gives the wrong sign or size.
- Q4Easy
Distance from origin to line 3x + 4y − 5 = 0:
A.5/7B.5C.1✓ CorrectD.0Answer: C. 1
Explanation: Distance from a point to Ax + By + C = 0 is |Ax₁ + By₁ + C|/√(A² + B²); at the origin that's just |C|/√(A²+B²) = |−5|/√25 = 1. Forgetting the √ and dividing by A²+B² directly is the standard slip.
- Q5Easy
Angle between two lines with slopes m₁, m₂ is:
A.m₁ + m₂B.m₂ − m₁C.tan θ = |(m₂ − m₁)/(1 + m₁m₂)|✓ CorrectD.Always 90°Answer: C. tan θ = |(m₂ − m₁)/(1 + m₁m₂)|
Explanation: The angle between two lines with slopes m₁, m₂ satisfies tan θ = |(m₂ − m₁)/(1 + m₁m₂)|. Dropping the absolute value or the +1 in the denominator is what turns this into the wrong, often negative, angle.
- Q6Easy
Slope-intercept form:
A.x + y = cB.x = my + cC.y = mx + c✓ CorrectD.y = m/xAnswer: C. y = mx + c
Explanation: y = mx + c is the slope-intercept form: m is the slope (rise per unit run) and c is the y-intercept, where the line crosses the y-axis at x = 0. Swapping which letter is which is the common trap.
- Q7Medium
Two non-vertical lines are parallel iff:
A.Slopes are equal✓ CorrectB.Slopes are negativesC.Product of slopes is −1D.Slopes differ by 1Answer: A. Slopes are equal
Explanation: Two non-vertical lines are parallel exactly when their slopes are equal, m₁ = m₂. The perpendicular condition m₁m₂ = −1 or a slope difference of exactly 1 are different relationships entirely.
- Q8Medium
Line through (1, 2) with slope 3:
A.y = 3x − 1✓ CorrectB.y = 3x + 1C.y = x + 2D.y = 3xAnswer: A. y = 3x − 1
Explanation: Point-slope: y − 2 = 3(x − 1) = 3x − 3, so y = 3x − 1. Forgetting to add back the 2 correctly, or mis-simplifying −3 + 2, is what produces y = 3x + 1 instead.
- Q9Medium
Slope of line through (1, 2) and (3, 4):
A.−1B.2C.1✓ CorrectD.0Answer: C. 1
Explanation: Slope = (4 − 2)/(3 − 1) = 2/2 = 1. Subtracting in the wrong order for just one coordinate — say (2−4)/(3−1) — flips the sign and gives −1 instead.
- Q10Medium
Distance from (0,0) to line 3x+4y=10:
A.5B.2✓ CorrectC.10D.1Answer: B. 2
Explanation: Write as 3x + 4y − 10 = 0, then |A·0 + B·0 + C|/√(A²+B²) = |−10|/√(9+16) = 10/5 = 2. Skipping the square root and dividing by 25 instead of 5 is the usual arithmetic slip.
- Q11Medium
Angle between lines y = 2x + 1 and y = (1/2)x − 1:
A.45°B.tan⁻¹(3/4)✓ CorrectC.30°D.60°Answer: B. tan⁻¹(3/4)
Explanation: tan θ = |(m₁ − m₂)/(1 + m₁m₂)| = |(2 − 1/2)/(1 + 2·1/2)| = |(3/2)/2| = 3/4, so θ = tan⁻¹(3/4). Forgetting the +1 in the denominator gives a different, wrong ratio.
- Q12Hard
Two lines are perpendicular iff:
A.m₁·m₂ = −1✓ CorrectB.m₁ = m₂C.m₁+m₂=0D.Both zeroAnswer: A. m₁·m₂ = −1
Explanation: Two lines are perpendicular exactly when the product of their slopes is −1, m₁·m₂ = −1 — each slope is the other's negative reciprocal. Equal slopes (m₁ = m₂) is the parallel condition, not this one.
- Q13Hard
If lines 2x + 3y − 6 = 0 and 4x + ky + 7 = 0 are parallel, k =
A.12B.3C.6✓ CorrectD.−3Answer: C. 6
Explanation: Parallel lines share a slope: 2x+3y−6=0 has slope −2/3, and 4x+ky+7=0 has slope −4/k. Setting −2/3 = −4/k gives k = 6. Cross-multiplying with a sign error is what flips the result to −6.
- Q14Hard
Foot of perpendicular from (1, 2) to line 4x − 3y − 12 = 0:
A.(3, 0)B.(2, 0)C.(81/25, 8/25)✓ CorrectD.(76/25, 47/25)Answer: C. (81/25, 8/25)
Explanation: Step from (1, 2) along the normal (4, −3). Since 4(1) − 3(2) − 12 = −14 and 4² + 3² = 25, the foot is (1, 2) + (14/25)(4, −3) = (81/25, 8/25). Substituting it back into the line gives 0, which is the check that it really lies on the line.
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Start this chapter free →Straight Lines — FAQs
What are the key concepts in Class 11 Mathematics Straight Lines?+
Coordinate geometry turns lines into equations. This chapter defines the slope of a line as the tangent of its inclination, derives the slope-intercept, point-slope, two-point, intercept and normal forms, reduces the general equation Ax + By + C = 0, and finds the angle between two lines and the distance of a point from a line. Key ideas include Slope of a line, Inclination, Parallel and perpendicular, Slope-intercept form.
What does Class 11 Mathematics Chapter 10 (Straight Lines) cover on XamBaaz?+
It has 90 NCERT-based MCQs on "Straight Lines": 30 Easy, 30 Medium and 30 Hard. Together they make 9 timed quizzes, and you never get the same set twice. Every question has an instant explanation. They help you prepare for CBSE & Maharashtra HSC Board exams, JEE Main, MHT-CET and JEE Advanced.
Are these "Straight Lines" questions free to practise?+
Yes. Sign in with Google to practise "Straight Lines" free. Full unlimited access is ₹999/year on a launch offer until 1 December 2026. No chapter is charged separately.
How should I revise "Straight Lines" for the exam?+
Start with the Easy quiz to check your basics, then try Medium and Hard to practise applying them. There are 9 timed quizzes on this chapter, so you can come back for a fresh set instead of one you have seen. Read each explanation, retry the questions you miss, and track your accuracy until it stays high.
Are these "Straight Lines" MCQs available with answers?+
Yes. 14 sample questions are shown here in full, each with the correct option and a step-by-step "Why" explanation. Sign in free with Google to start practising, with instant scoring.
Is there negative marking in the "Straight Lines" quizzes?+
Yes. The timed quizzes use exam-style marking: +4 for a right answer, −1 for a wrong one and 0 for a skip, the same negative marking as JEE Main and JEE Advanced. MHT-CET and CBSE board papers have no negative marking. Our mocks for those are scored their way.
What are the important questions from Straight Lines (Class 11 Mathematics)?+
The questions that matter most test Slope of a line, Inclination, Parallel and perpendicular, Slope-intercept form. This page shows 14 solved important MCQs with answers and explanations; all 90 questions on the chapter are available as timed quizzes once you sign in.
Is there an online quiz for Straight Lines?+
Yes — Class 11 Mathematics Straight Lines has timed online quizzes at Easy, Medium and Hard levels, with instant scoring and a worked explanation on every question. The first quiz on the chapter is free.