The ratio of the length of a vertical rod to the length of its shadow is 1 : √3. What is the angle of elevation of the Sun?
Aptitude
Height and Distance
Difficulty: Easy
Choose an option
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A30°
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B45°
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C60°
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D90°
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E15°
Answer
Correct Answer: 30°
Explanation
Introduction / Context:Shadow problems convert to tan θ = height / shadow. A given ratio directly yields θ by matching to standard angles.
Given Data / Assumptions:
- Height : shadow = 1 : √3 ⇒ height/shadow = 1/√3.
Concept / Approach:tan θ = height/shadow = 1/√3. Standard angles give tan 30° = 1/√3, so θ = 30°.
Step-by-Step Solution:
tan θ = 1/√3 ⇒ θ = 30°.Verification / Alternative check:If θ were 45°, the ratio would be 1 : 1; if 60°, the ratio would be √3 : 1. Neither matches 1 : √3.
Why Other Options Are Wrong:45° and 60° correspond to different tangent values; 90° would give zero shadow (not this ratio), 15° gives much larger shadow.
Common Pitfalls:Inverting the ratio; using sine instead of tangent for shadow length.
Final Answer:30°