Refraction is the change in direction of a wave.
Diffraction is the bending of a wave around a barrier.
To solve this problem we will apply the concepts related to the Doppler effect. The Doppler effect is the change in the perceived frequency of any wave movement when the emitter, or focus of waves, and the receiver, or observer, move relative to each other. Mathematically it can be described as

Here,
=frequency received by detector
=frequency of wave emitted by source
=velocity of detector
=velocity of source
v=velocity of sound wave
Replacing we have that,


Therefore the frequencty that will hear the passengers is 422Hz
Explanation:
Power of electric kettle, P = 1 kW
Voltage, V = 220 V
(a) Electric power is given by the formula as follows :

R is resistance

(b) When connected to a 220 V supply, it takes 3 minutes for the water in the kettle to reach boiling point.
Energy supplied is given by :

P is power, 

This question is incomplete; here is the complete question:
A phoneme is the largest unit of sound in a word. Please select the best answer from the choices provided
A. T
B. F
The correct answer to this question is F (False)
Explanation:
The word "phoneme" is used to refer to the minimal unit of sound in words, and therefore in language. For example, the first phoneme in the word "man" is "m". These units of sound are essential in language because they make each word unique in meaning and sound. For example, "fan" and "man" are different due to the phonemes "m" and "f". According to this, the phone is not the largest unit of sound but the smallest unit.
Q= mcΔT
Where Q is heat or energy
M is mass, c is heat capacitance and t is temperature
You have to convert Celsius into kelvin in order to use this formula I believe
Celsius + 273 = Kelvin
21 + 273 = 294K
363 + 273 = 636K
Now...
Q= (0.003)(0.129)(636-294)
Q= 0.132 J if you are using kilograms, in terms of grams which seems more appropriate the answer would be 132J of energy.