To develop this problem it is necessary to apply the concepts related to a magnetic field in spheres.
By definition we know that the magnetic field in a sphere can be described as
Where,
a = Radius
z = Distance to the magnetic field
I = Current
Permeability constant in free space
Our values are given as
diameter of the sphere then,
Thus z = a
Re-arrange to find I,
Therefore the current at the pole of this sphere is 
Answer;
the potential difference
The magnitude of the electric current is directly proportional to the potential difference of the electric field
Explanation;
An electric current results from the collective movement of free charges under the effect of an electric field. An electric field exists and can be observed in the space around a single charge or a number of charges.
Electric fields cause charges to move. It stands to reason that an electric field applied to some material will cause currents to flow in that material. In other words, the current density is directly proportional to the electric field. The constant of proportionality σ is called the material’s conductivity.
1) 29.8 C
At the beginning, the metal is at higher temperature (70.4 C) while the water is at lower temperature (23.6 C). When they are put in contact, the metal transfers heat to the water, until they reach thermal equilibrium: at thermal equilibrium the two objects (the metal and the water have same temperature). Therefore, since the temperature of the water at thermal equilibrium is 29.8 C, the final temperature of the metal must be the same (29.8 C).
2) 6.2 C
The temperature change of the water is given by the difference between its final temperature and its initial temperature:
where
Substituting into the formula,
And the positive sign means that the temperature of the water has increased.
3) -40.6 C
The temperature change of the metal is given by the difference between its final temperature and its initial temperature:
where
Substituting into the formula,
And the negative sign means the temperature of the metal has decreased.
1) By looking at the table of the visible spectrum, we see that blue light has a wavelength in the range [450-490 nm], while red light has wavelength in the range [620-750 nm]. Therefore, red light has longer wavelength than blue light.
2) The frequency f of an electromagnetic wave is related to its wavelength
by the formula
where c is the speed of light. We see that the frequency is inversely proportional to the wavelength, so the shorter the wavelength, the greater the frequency. In this case, blue light has shorter wavelength than red light, so blue light has greater frequency than red light.
3) The energy of the photons of an electromagnetic wave is given by
where h is the Planck constant and f is the frequency. We see that the energy is directly proportional to the frequency, so the greater the frequency, the greater the energy. In this problem, blue light has greater frequency than red light, so blue light has also greater energy than red light.
Answer:
A.reduce by 4.
Explanation:
In Chemistry, an alpha particle which is typically a helium nucleus has an atomic mass (number of nucleons) of four (4). Therefore, the ejection of an alpha particle by any chemical element simply means that, the mass number of that particular chemical element would be reduced by four (4).
Basically, this process is referred to as an alpha decay and can be defined as a radioactive disintegration of a chemical element that causes it to emit an alpha particle and as a result reducing its mass number by four (4).
Hence, when an element ejects an alpha particle, the mass number of that element reduces by 4.
