Question

The head lights of a jeep are $1.2\, m$ apart. If the pupil of the eye of an observer has a diameter of $2\, mm$ and light of wavelength $5896\, ?$ is used, what should be the maximum distance of the jeep from the observer if the two head lights are just separated?

• A. 33.9 km
• B. 33.9 m
• C. 3.34 m
• D. 3.39 m

Answer 1

Answer: (C)

3.34 m

Answer 2

Distance of jeep, $x = \frac{D \times d}{1.22 \times \lambda }$ where D = diameter of lens, d = seperation between sources . $\Rightarrow \; x = \frac{(2 \times 10^{-3}) \times 1.2}{1.22 \times 5896 \times 10^{-10}}$ $= 3336\, m$ $\Rightarrow\, x = 3.34 \,m$