A telescope has an objective lens of focal length 150 cm and an eyepiece of focal length 5 cm . If a 50 m tall tower at a distance of 1 km is observed through this telescope in a normal setting, the angle formed by the image of the tower is θ , then θ is close to

Step-by-step solution

Angular magnification of a telescope in normal adjustment is m = β α = f 0 f e ⇒ β = f 0 f e α According to the question α = y x = 50 1000 = 1 20 ⇒ α = 1 20 ⇒ β = 150 5 × 1 20 = 32   rad = 3 2 × 180 ° 3 . 14 = 86 °