Unit 1: C1 Working with Waves

Question 1

What is periodic time in the context of waves?

Answer 1

Periodic time is the time taken for one complete cycle of a wave to pass a given point. It is the inverse of frequency.

Question 2

How is the speed of a wave calculated?

Answer 2

Wave speed is calculated using the formula: Wave speed = Frequency × Wavelength.

Question 3

Define wavelength in relation to waves.

Answer 3

Wavelength is the distance between two consecutive points in phase on a wave, such as two crests or troughs.

Question 4

What is amplitude in a wave?

Answer 4

Amplitude is the maximum displacement of a point on a wave from its rest position, indicating the wave’s energy.

Question 5

What is the difference between transverse and longitudinal waves?

Answer 5

In transverse waves, oscillations are perpendicular to the direction of wave travel, while in longitudinal waves, oscillations are parallel to the direction of wave travel.

Question 6

Provide examples of transverse and longitudinal waves.

Answer 6

Examples of transverse waves include light and water waves. An example of a longitudinal wave is sound.

Question 7

What is meant by displacement in wave terms?

Answer 7

Displacement refers to the distance and direction of a point on the wave from its equilibrium position.

Question 8

Define coherence in the context of waves.

Answer 8

Coherence refers to waves that have a constant phase difference and the same frequency, which allows for predictable interference patterns.

Question 9

What is superposition in waves?

Answer 9

Superposition occurs when two or more waves overlap, and their displacements combine to form a resultant wave.

Question 10

How does a diffraction grating demonstrate path and phase difference?

Answer 10

A diffraction grating splits light into several beams by creating path differences between light waves, resulting in constructive and destructive interference depending on their phase difference.

Question 11

What is the wave equation and how is it used?

Answer 11

The wave equation is v=fλ where
𝑣 is wave speed,
𝑓 is frequency, and
𝜆 is wavelength.
It is used to calculate the speed of a wave

Question 12

How can you calculate the wavelength of a wave if you know its speed and frequency?

Answer 12

Use the formula:
𝜆 = 𝑣/𝑓
where
𝑣 is wave speed and
𝑓 is frequency.

Question 13

What is a stationary wave?

Answer 13

A stationary wave is formed when two waves of the same frequency and amplitude traveling in opposite directions interfere, creating nodes and antinodes.

Question 14

What is resonance in stationary waves?

Answer 14

Resonance occurs when a an object is driven to oscillate at its natural frequency, leading to large amplitude oscillations, such as in musical instruments.

Question 15

How do stationary waves apply to musical instruments?

Answer 15

In instruments like strings or wind instruments, stationary waves create specific frequencies (harmonics) that produce musical notes.

Question 16

What determines the pitch of a note produced by a string instrument?

Answer 16

The pitch depends on the string’s length, tension, and mass per unit length, which affect the wave’s frequency.

Question 17

How does increasing tension affect the speed of a wave in a string?

Answer 17

Increasing tension increases the wave speed, as speed is directly proportional to the square root of tension.

Question 18

What is the formula for calculating wave speed in a stretched string?

Answer 18

The formula is
v = √(T /μ)
​where
T is tension in the string and
μ is mass per unit length.

Question 19

What is the industrial application of diffraction gratings in emission spectra?

Answer 19

Diffraction gratings are used to separate light into its component wavelengths, allowing scientists to analyse emission spectra and identify the elements present in a light source.