White objects do not absorb all wavelenghts. The statement is false
<span>Nodes are points along the medium that appear to be standing still. They are points on a standing wave that has no displacement from the rest position.
Antinodes are the opposite of nodes. Those are</span> points that undergo the maximum displacement.
<span>At the nodes the destructive interference occurs</span> . For example <span>a crest of one wave meets a trough of a second wave</span> , or a half-crest of one wave meets a half-trough of a second wave...
Answer:
The working of an electric motor is based on the assumption that a conductive current generates a magnetic field around it. Consider the following situation,
Take two bar magnets, and leave a small space between the poles facing each other. Now, take a small conductive wire length and make a loop. Keep this connection between the magnets, so that it is still inside the magnet’s area of influence. Now for the final part. Attach loop ends to battery terminals.
As electricity flows through your simple circuit, you will find that your loop “moves.” The magnet’s magnetic field interferes with that generated by the conductor’s electrical current flow. Because the loop has become a magnet, it will draw one side of it to the magnet’s north pole, and the other to the south pole. That causes the loop to rotate continuously. This is the idea of an electric motor working.
Answer: T = 472.71 N
Explanation: The wire vibrates thus making sound waves in the tube.
The frequency of sound wave on the string equals frequency of sound wave in the tube.
L= Length of wire = 26cm = 0.26m
u=linear density of wire = 20g/m = 0.02kg/m
Length of open close tube = 86cm = 0.86m
Sound waves in the tube are generated at the second vibrational mode, hence the relationship between the length of air and and wavelength is given as
L = 3λ/4
0.86 = 3λ/4
3λ = 4 * 0.86
3λ = 3.44
λ = 3.44/3 = 1.15m.
Speed of sound in the tube = 340 m/s
Hence to get frequency of sound, we use the formulae below.
v = fλ
340 = f * 1.15
f = 340/ 1.15
f = 295.65Hz.
f = 295.65 = frequency of sound wave in pipe = frequency of sound wave in string.
The string vibrated at it fundamental frequency hence the relationship the length of string and wavelength is given as
L = λ/2
0.26 = λ/2
λ = 0.52m
The speed of sound in string is given as v = fλ
Where λ = 0.52m f = 295.65 Hz
v = 295.65 * 0.52
v = 153.738 m/s.
The velocity of sound in the string is related to tension, linear density and tension is given below as
v = √(T/u)
153.738 = √T/ 0.02
By squaring both sides
153.738² = T / 0.02
T = 153.738² * 0.02
T = 23,635.372 * 0.02
T= 472.71 N
