Q.

Assertion (A): If the ratio of the height of a pole and its shadow is 3:1, then the Sun’s altitude is 30°.

Reason (R): In a right triangle, tanθ=pb, where p stands for perpendicular (opposite side to angle θ) and b for base (adjacent side).

1 Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A)  
2 Both assertion (A) and reason (R) are true and reason (R) is not the correct explanation of assertion (A)  
3 Assertion (A) is true but reason (R) is false.  
4 Assertion (A) is false but reason (R) is true.  

Ans.

(4)

Let AB be the pole and BC be its shadow on the ground.

Here,

AB:BC=3:1 and  let ∠ACB=θ.In∆ABC,we have:tanθ=ABBC=31=3⇒tanθ=tan60°⇒θ=60°⇒{Sun’s altitude is 60∘.

Hence, Assertion (A) is false.

Also, the fact given under Reason (R) is the definition of tangent. So, Reason (R) is true.