Question

question 3 of 10
in which direction does a wave bend when it slows down upon entering a denser medium?
towards the normal
backwards
parallel to surface
away from normal

Explanation:

Identify the wave behavior

The question asks about the direction a wave bends when it slows down upon entering a denser medium. This phenomenon is known as Wave Refraction.

Analyze the physical principles

When a wave travels from a less dense medium to a denser medium, its speed decreases. According to Snell's Law, the relationship between the angles and wave speeds is given by:

$$ \frac{\sin(\theta_1)}{\sin(\theta_2)} = \frac{v_1}{v_2} $$

where \(\theta_1\) is the angle of incidence, \(\theta_2\) is the angle of refraction, \(v_1\) is the speed in the first medium, and \(v_2\) is the speed in the second medium.

Determine the bending direction

Since the wave slows down in the second medium, we have:

$$ v_2 < v_1 $$

This implies:

$$ \sin(\theta_2) < \sin(\theta_1) \implies \theta_2 < \theta_1 $$

Because the angle of refraction \(\theta_2\) is smaller than the angle of incidence \(\theta_1\) relative to the normal line, the refracted wave path bends closer to the normal line. Therefore, the wave bends towards the normal.

Answer:

• Towards the normal (Correct answer)
• Backwards
• Parallel to surface
• Away from normal