D) CAN BE SMALLER OR BIGGER THAN THE OPAQUE BODY because we can not say that it is bigger or smaller

Understanding the Size of Shadows in Relation to Opaque Bodies

Introduction:
When light is obstructed by an object, it creates a shadow. Shadows have fascinated humans for centuries, and understanding their size in relation to the opaque body is crucial. Let us explore the various possibilities in detail.

Explanation:
Shadows can vary in size based on several factors. Here are the different scenarios:

1. Shadows are always smaller than the opaque body:
- In most cases, when an opaque body blocks the path of light, the resulting shadow will indeed be smaller.
- This occurs when the light source is positioned close to the opaque body, and the surface on which the shadow is cast is far away.
- The shadow's size decreases as the distance between the opaque body and the surface increases.

2. Shadows are always bigger than the opaque body:
- This scenario is highly unlikely and does not occur in practical situations.
- A shadow can only be larger than the opaque body if the light source is positioned in such a way that it casts the shadow in the opposite direction of the body.
- However, this is an uncommon occurrence and not applicable to most real-life situations.

3. Shadows remain the same size as the opaque body:
- This situation is also highly unlikely and not commonly observed.
- For the shadow to remain the same size as the opaque body, the light source would need to be positioned at an infinite distance from both the body and the surface on which the shadow is cast.
- In practical scenarios, where the light source is finite and at a reasonable distance, the shadow will either be smaller or larger than the opaque body.

4. Shadows can be smaller or bigger than the opaque body:
- This is the most accurate statement and applicable to most real-life situations.
- The size of the shadow depends on the relative positions of the light source, opaque body, and the surface on which the shadow is cast.
- Factors such as distance, angle of incidence, and the size of the opaque body contribute to the varying sizes of shadows.

Conclusion:
In conclusion, shadows are not always smaller or bigger than the opaque body. The size of the shadow depends on the relative positions of the light source, opaque body, and the surface on which the shadow is cast. Therefore, the correct answer is option 'D' - shadows can be smaller or bigger than the opaque body, depending on the specific circumstances.