The magnitude of the magnetic field that a long and extremely thin current-carrying wire produces at a distance of 3.0 µm from t
2 answers:
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Answer:
236.3 x C
Explanation:
Given:
B(0)=1.60T and B(t)=-1.60T
No. of turns 'N' =100
cross-sectional area 'A'= 1.2 x m²
Resistance 'R'= 1.3Ω
According to Faraday's law, the induced emf is given by,
ℰ=-NdΦ/dt
The current given by resistance and induced emf as
I = ℰ/R
I= -NdΦ/dtR
By converting the current to differential form(the time derivative of charge), we get
= -NdΦ/dtR
dq= -N dΦ/R
The change in the flux dФ =Ф(t)-Ф(0)
therefore, dq = (Ф(0)-Ф(t))
Also, flux is equal to the magnetic field multiplied with the area of the coil
dq = NA(B(0)-B(t))/R
dq= (100)(1.2 x )(1.6+1.6)/1.3
dq= 236.3 x C
1. False
Explanation: it's exactly the opposite. In fact, Lenz's law states that the induced current and the induced emf in a conductor are generated in such a direction that opposes to the change in magnetic flux through the coil. This is summarized by the negative sign in the Faraday's Newmann Lenz law:
where is the emf induced and
is the rate of change of magnetic flux through the coil.
Lenz's law is a consequence of the law of conservation of energy. In fact, we have:
- If the magnetic flux through a coil is increasing, then the induced current has a direction such that the magnetic field generated by the coil is opposite to the direction of the external magnetic field, in order to decrease the total flux
- If the magnetic flux through a coil is decreasing, then the induced current has a direction such that the magnetic field generated by the coil is in the same direction as the external field, in order to increase the total flux
2. False
Explanation: the magnetic flux through a surface is given by
where
B is the magnitude of the magnetic field
A is the surface area
is the angle between the direction of B and the normal vector to the surface
As we see, the magnetic flux depends not only on B and A, but also on the orientation of the coil with respect to the magnetic field.
3. False
Explanation:
- Sound waves are mechanical waves: mechanical waves are waves consisting of oscillations of the particles in a medium. Due to their nature, therefore, mechanical waves can propagate only in the presence of a medium
- Electromagnetic waves are NOT mechanical waves: they consist of oscillations of electric and magnetic fields, in a direction perpendicular to the direction of propagation of the wave. Since em waves are not mechanical waves, they do NOT need a medium to propagate, since they can also travel through a vacuum; therefore the original statement is false.
Answer:
They can be rank in the following way:
- A radio signal from an AM radio station at 680 kHz on the dial
- Radiation from an FM radio station at 93.1 MHz on the dial
- The red light of a light-emitting diode, such as in a calculator
- The yellow light from sodium vapor streetlights
- The gamma rays produced by a radioactive nuclide used in medical
Explanation:
The electromagnetic spectrum is the distribution of radiation due to the different frequencies at which it radiates and its different intensities, that radiation is formed by electromagnetic waves, which are transverse waves formed by an electric field and a magnetic field perpendicular to it.
Radiation is distributed along that electromagnetic spectrum according to the wavelength or frequency.
Highest frequencies
X-rays
Ultraviolet rays
Visible region
Lower frequencies
Infrared
Microwave
Radio waves
Radio waves and the visible region (yellow light, red light) are part of the electromagnetic spectrum, any radiation of that electromagnetic spectrum has a speed of 3.00x10^{8}m/s in vacuum.
However, the following equation relates the velocity, the frequency, and the wavelength:
(1)
(2)
It can be see in equation 2 that the frequency and the wavelength are inversely proportional (when the frequency increases the wavelength decreases).
Therefore, for what was already discussed, they can be rank in the next way:
- A radio signal from an AM radio station at 680 kHz on the dial
- Radiation from an FM radio station at 93.1 MHz on the dial
- The red light of a light-emitting diode, such as in a calculator
- The yellow light from sodium vapor streetlights
- The gamma rays produced by a radioactive nuclide used in medical
Summary:
In the case of the radio waves can be used:
Case for :
Case for :