CBSE Class 10 Mathematics Standard 2024: question 19
Set in the CBSE Class 10 board exam of 2024, paper 30/1/1, section A, question 19, for 1 mark. Try it first; the hints and our step-by-step solution are below.
Q19 · 1 mark · Assertion-reasonCompetency-basedCircles
Assertion (A): The tangents drawn at the end points of a diameter of a circle, are parallel.
Reason (R): Diameter of a circle is the longest chord.
- (A)Both, Assertion (A) and Reason (R) are true and Reason (R) is correct explanation of Assertion (A).
- (B)Both, Assertion (A) and Reason (R) are true but Reason (R) is not correct explanation for Assertion (A).
- (C)Assertion (A) is true but Reason (R) is false.
- (D)Assertion (A) is false but Reason (R) is true.
Source: official question paper from cbse.gov.in (PDF). See it in the full 2024 board paper, set 30/1/1.
Hints
Open one hint at a time and try again before the next.
Hint 1
What is the angle between a tangent and the radius at the point of contact?
Hint 2
Check whether 'longest chord' is actually used in proving the lines are parallel.
Step-by-step solution
Each step shows the marks it earns, as an examiner would award them. Checked by an independent re-solve from the question paper.
Assertion: each tangent is perpendicular to the radius at its point of contact, so both tangents are perpendicular to the same diameter. Hence they are parallel, and A is true.
- 1 mark
Reason: the diameter is indeed the longest chord, so R is true. However, the parallelism comes from 'tangent ⟂ radius', not from the diameter being longest. So R does not explain A, and the answer is option (B).
Answer: Option (B)
Where the marks are
- Judges both statements true, with R not explaining A, option (B) (1 mark)
Revise the chapter
- Chapter: Circles (notes, formulas, where marks are lost and every past question)
- Topic: Solving Problems Using Tangent Properties
More questions from Circles
- 2024 board paper, set 30/1/1 (Standard), Q30(A) · 3 marksIn the given figure, AB is a diameter of the circle with centre O. AQ, BP and PQ are tangents to the circle. P…
- 2024 board paper, set 30/3/1 (Standard), Q31 · 3 marksProve that the tangents drawn at the end points of a chord of a circle makes equal angles with the chord.
- 2024 board paper, set 30/4/1 (Standard), Q31 · 3 marksProve that the parallelogram circumscribing a circle is a rhombus.
The question is transcribed from the official paper; figures are described in words. The solution, hints and chapter tag are ours. Spotted an error? Write tosupport@questionbuddy.in.