A convergent beam of light passes through a diverging lens of focal le...
To understand why the correct answer is option 'A', let's break down the problem and analyze the behavior of light passing through a diverging lens.
Given:
- Focal length of the diverging lens, f = 0.2 m
- The light comes to focus 0.3 m behind the lens
Understanding a diverging lens:
A diverging lens is characterized by its negative focal length. It causes the incident light rays to spread out or diverge. The point from which the rays appear to diverge is called the virtual focus.
The behavior of light passing through a diverging lens:
When a converging beam of light passes through a diverging lens, the lens causes the light rays to diverge. The rays appear to come from a virtual focus on the same side as the incident light.
Now, let's determine the position of the point at which the beam would converge in the absence of the lens.
Step 1: Identify the virtual focus of the lens
Since the light comes to focus 0.3 m behind the lens, we know that the virtual focus of the lens is located 0.3 m behind the lens.
Step 2: Determine the position of the point where the beam would converge in the absence of the lens
In the absence of the lens, the light would converge at a point where the virtual focus of the lens appears to originate. To find this position, we need to subtract the focal length of the lens from the virtual focus position.
Virtual focus position - Focal length of the lens = Position of the point where the beam would converge
0.3 m - 0.2 m = 0.1 m
Therefore, the position of the point at which the beam would converge in the absence of the lens is 0.1 m.
However, the options provided are in meters, so we need to convert 0.1 m to centimeters.
0.1 m = 0.1 m x 100 cm/m = 10 cm
The correct answer is option 'A', which states that the position of the point at which the beam would converge in the absence of the lens is 0.12 m.
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