Class 10 Maths Chapter 9 Assertion and Reason Questions - Some Applications of Trigonometry

Directions: In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:
Question 1:
Assertion (A) : If the length of shadow of a vertical pole is equal to its height, then the angle of elevation of the sun is 450 
Reason (R) : According to pythagoras theorem, h² = l² + b², where h = hypotenuse, l = length and b = base.
(a) Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A)
(b) Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).
(c) Assertion (A) is true but reason (R) is false.
(d) Assertion (A) is false but reason (R) is true.

Correct Answer is Option (b)

Both Assertion and Reason are correct, but Reason is not the correct explanation of the Assertion.

Question 2:
Assertion (A) : In the figure, if BC = 20 m, then height AB is 11.56 m.

Reason (R) : where θ is the angle ∠ACB.
(a) Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).
(b) Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).
(c) Assertion (A) is true but reason (R) is false.
(d) Assertion (A) is false but reason (R) is true.

Correct Answer is Option (a)

Both the assertion and reason are correct, reason is the correct explanation of the assertion.

Question 3:
Assertion (A) : The line of sight  is the line drawn from the eye of an observer to the point in the object viewed by the observer.
Reason (R) : Trigonometric ratios are used to find height or length of an object or distance between two distant
(a) Both assertion and reason are correct and reason is correct explanation for assertion.
(b) Both Assertion and Reason are correct but reason is not correct explanation for assertion.
(c) Assertion is correct but reason is false.
(d) Both Assertion and Reason are false.

Correct Answer is Option (b)

Both assertion and reason are correct and reason is correct explanation for assertion.

Question 4:

Assertion (A) : The angle of elevation of an object viewed, is the angle formed by the line of sight with the horizontal when it is above the horizontal level.
Reason (R) : The angle of depression. of an object viewed, is the angle formed by the line of sight with the horizontal when it is below the horizontal level.
(a) Both assertion and reason are correct and reason is correct explanation for assertion.
(b) Both Assertion and Reason are correct but reason is not correct explanation for assertion.
(c) Assertion is correct but reason is false.
(d) Both Assertion and Reason are false.

Correct Answer is Option (b)

Both assertion and reason are correct and reason is correct explanation for assertion.