Educational worksheet on refraction of light, featuring diagrams and questions about light bending in water.

Let me work through each part of this problem step by step.

1(a) Name the phenomenon involved in diagram 1:

The pencil appears bent when placed in water. This is refraction.

1(b) Explain how the light phenomenon occurs:

Refraction happens because light travels at different speeds in different materials (air and water). When light rays from the pencil travel from water to air, they change direction (bend) at the boundary between water and air. Our eyes see the light coming from a different position than where the pencil actually is, making it appear bent.

1(c) Why did the spear fail to hit the fish?

When looking at the fish underwater, light rays from the fish bend as they travel from water to air (refraction). The man sees the fish at position Z (apparent position), which appears shallower than the actual position X. He aims his spear at where he sees the fish (Z), but the real fish is deeper at position X. That's why he missed.

1(d) Calculate the refractive index of water:

Given:
- Speed of light in air (c) = 3.0 × 10 m/s
- Speed of light in water (v) = 2.0 × 10⁸ m/s

Formula: n = c/v

n = (3.0 × 10)/(2.0 × 10⁸)
n = 3.0/2.0
n = 1.5

Correct sequence:
1 → List down all values given
2 → Use formula n = c/v

1(e) Calculate the real depth of the fish:

Given:
- Apparent depth (h) = 3.0 m
- Refractive index (n) = 1.5
- Real depth (H) = ?

Formula: n = H/h

Rearranging: H = n × h

H = 1.5 × 3.0
H = 4.5 m

Let me verify: If n = H/h, then 1.5 = H/3.0, so H = 1.5 × 3.0 = 4.5 m ✓

Correct sequence:
1 → List down all values given
2 → Use formula n = H/h
3 → Substitute: 1.5 = H/3.0
4 → Solve: H = 4.5 m

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Final Answer:

1(a) Refraction

1(b) Light travels at different speeds in water and air. When light rays pass from water to air, they bend (change direction) at the boundary. Our eyes perceive the light as coming from a different position, making objects appear displaced or bent.

1(c) Due to refraction, the fish appears at a shallower position (Z) than its actual position (X). The man aimed at the apparent position, but the real fish was deeper, so the spear missed.

1(d) Refractive index of water = 1.5
Sequence: 1, 2

1(e) Real depth of the fish = 4.5 m
Sequence: 1, 2, 3, 4