Explanation:
Doppler's Effect: If a source is moving towards the observer the frequency of the waves emitted by the source will increase( wavelength will decrease). If the source is moving away from the observer the frequency of the waves emitted by the source will decrease( wavelength will increase). The best example of this is the changing frequency of siren of an ambulance as it moves towards us and then away from us.
The same phenomenon can be observed in celestial objects. When the object will move towards us the wavelength will decrease thus the spectrum will be shifted towards the blue part. This is known as blue shift.
If the object moves away from us the wavelength will increase and thus the spectrum will be shifted towards red part. This is know as Red-shift. This is because red has longer wavelength (620 - 750nm) than blue (450-495nm)
Thus if a galaxy shows us red-shifted spectra it means that it is moving away from us. we have observed this phenomenon in various galaxies thus supporting the expanding universe theory.
Answer:
Explanation:
We have a metal ring of diameter
d = 4.2cm = 0.042m
r = d/2 = 0.021m
And it is place between the north pole and south pole of a large magnet with the plane of it's area perpendicular to the magnetic field.
Given that the magnetic field is
B = 1.12 T
The rate of decrease of magnetic field is 0.2T/s, since it is decrease then,
dB/dt = -0.2 T/s
The induce electric field is given as,
From faradays law
ε = ∫E•dl = -dΦ/dt
Magnetic flux is given as
Φ = BA
Φ = πr²×B = πr²B
Also, ∫E•dl = E×2πr = 2πrE
So,
∫E•dl = -dΦ/dt
2πrE = -d(πr²B) / dt
r is a constant, then
2πrE = -πr² dB/dt
Divide both side by πr
2E = -r dB/dt
E = -r dB/dt / 2
E = -0.021 × -0.2 / 2
E = 0.0021 V/m
The magnetic field point from north to south pole and it is decreasing and this means that the magnetic flux is also decreasing, so the induce magnetic field must point in the same direction of the original magnetic field, so the induce current circulate counter-clockwise as viewed from the south pole
To increase the potential energy of any object, not limited to an apple, you have to hold it higher.
