Real Depth vs Apparent Depth — Difference (with Table & FAQs)
Real Depth vs Apparent Depth compared side by side — a 6-row comparison table, 4 key points and 3 exam FAQs. Class 10 Physics, free and no sign-up.
TL;DR: Real Depth vs Apparent Depth compared side by side — a 6-row comparison table, 4 key points and 3 exam FAQs. Class 10 Physics, free and no sign-up.
Written & reviewed by the Syllab.in Academic Team (CBSE/NCERT subject experts) · Updated
The main difference between Real Depth and Apparent Depth: Real depth is the actual distance from the surface to an object measured in the medium. Apparent depth is the distance from the surface to where the object
Real Depth vs Apparent Depth — Comparison Table
| Basis | Real Depth | Apparent Depth |
|---|---|---|
| Definition | Actual distance of object from surface | Distance object appears to be from surface |
| Measurement Method | Measured directly with a scale | Perceived from observation due to refraction |
| Value | Always greater than apparent depth in denser medium | Always less than real depth in denser medium |
| Cause of Difference | No refraction involved | Light refraction at interface causes it |
| Refractive Index Role | Not directly affected by refractive index | Depends on refractive index of medium |
| Example | A fish at 30 cm below water surface | The fish appears at about 22 cm depth due to refraction |
Key Points
- Refraction at air-water interface causes apparent depth difference
- Relationship: apparent depth = real depth / refractive index
- The denser the medium, the greater the difference between real and apparent depth
- Apparent depth helps explain why objects appear closer when viewed through water
Frequently Asked Questions
What is the difference between real depth and apparent depth?
Real depth is the true distance from the surface of a liquid to an object in it. Apparent depth is the shallower depth at which the object appears to be when viewed from above, because light bends as it leaves the water.
Why does a pond look shallower than it is?
Light travelling from the object to your eye refracts away from the normal as it passes from water into air. Your eye traces those rays back in straight lines, and they meet at a point higher than the object actually is.
Which is greater, real depth or apparent depth?
Real depth is always greater for an object viewed from air through a denser medium such as water. This is why a swimming pool looks shallower than it is, and why a straw in a glass appears bent at the surface.