Question

Pinhole camera is a simple application of:
A. reflection of light
B. rectilinear propagation of light
C. refraction of light
D. scattering of light

Answer 1

Hint: A pinhole camera is a simple camera. Here when the light passes through a small aperture or opening on one side of the box, then we observe an inverted image when viewed through the other side. This effect is called the obscura effect.

Complete answer:
We know that light travels in all the possible directions in straight lines; this property of the light is called the rectilinear propagation of light. This was the first study of light and its properties which was proposed by the Arab physicist Ibn al-Haytham.
A pinhole camera is a simple application of rectilinear propagation of light. A few uses of a pinhole camera are, it used to study the movement of sun for a longer span of time. It is also used to understand the pupils of the eyes. Some characteristics of a pinhole camera are:
1. The images appear to be in focus or there is infinite depth of field in the photographs.
2. Due to absence of lens there is no distortion.
3. Moving objects look blurred through a pinhole camera.
The light rays falling through the small opening of the leaves is a natural phenomenon of a pin-hole camera.

So, the correct answer is “Option B”.

Note:
The camera obscura is a natural phenomenon in optics. This phenomenon was used in photography in the early days. However these days, in cameras we have lenses which invert the inverted images. Thus we observe that the image is erect or upright as the object itself.