**Answer:**

**Explanation:**

The number of oscillation per unit time is called frequency of a wave while the distance between two consecutive crests and the trough is called its wavelength.

**The wavelength of a wave is given by :**

If frequency is doubled, f' = 2f

**So, when the frequency is doubled the wavelength of a wave on the string becomes half. **

**Answer:**

Wavelength

**Explanation:**

Wavelength is the distance between two corresponding consecutive phases of a waveform. It is usually represented by **λ **in the mathematical expressions.

A continuous propagating wave repeats its wavelength over the distance.

A wave has crest and trough with respect to time and space.

**Wave **is defined as a disturbance of any parameter repeated in a cyclic manner over the given time.

The element number 17 is associate with Chrlorine which has 17 protons and 18 neutrons.

**Answer:**

83.74 cm

**Explanation:**

The air column over water level will act as vibrating air column creating standing sound waves . Third resonance occurs when length of water column becomes equal to 5 x λ / 4 . where λ is wave length of sound.

In resonance frequency of air column and tuning fork becomes equal .

Here if L be the length of air column for third resonance

L = 5 x λ / 4

frequency of tuning fork = 512

wavelength of sound produced = velocity of sound / frequency

343 / 512

λ = .6699 m

L = 5 x .6699 / 4

= .8374 m

= 83.74 cm .

water level will be 83.74 cm deep.