A stroboscope can be used to make the wave appear …………..

Analysis

The question asks for the effect of using a stroboscope on a wave. A stroboscope is an instrument used to make a cyclically moving object appear to be slow-moving or stationary.

Concept Explanation

A stroboscope works by emitting short, rapid flashes of light at a specific frequency. When the frequency of the flashes matches the frequency of the wave (or is a multiple of it), the wave appears to be "frozen" in time. This phenomenon is known as stroboscopic effect.

In physics experiments involving ripples in a ripple tank, we use a stroboscope to observe the wavelength and frequency of the waves more clearly. By adjusting the flash rate, we can make the rapidly moving wave crests appear to stop moving, allowing us to measure them accurately.

Step-by-Step Solution

1. Identify the function of the device: A stroboscope is designed to observe periodic motion.
2. Relate to wave motion: When a wave is moving at a high frequency, it is difficult for the human eye to track individual crests or troughs.
3. Apply the strobe effect: By flashing light at the same frequency as the wave, the eye only sees the wave at the same position in each cycle.
4. Conclusion: Because the eye sees the wave at the same position repeatedly, the brain perceives the wave as not moving at all.

Identifying the Answer

Comparing this to the options provided:

• A. Stationary: This matches the physical principle of the stroboscopic effect.
• B. In motion: This is what the wave is doing naturally, but the stroboscope is used to stop this perception.
• C. Dipper: This is a component of a ripple tank, not the effect of a stroboscope.
• D. Ripple: This is the object being observed, not the visual effect produced.

Exam Tip

Whenever you see a question about a "stroboscope" in your Physics exam, immediately associate it with the word "stationary" or "frozen." It is a common trick in JAMB to ask about the purpose of this device; just remember it is used to "stop" motion for easier measurement.