Answer: 
Explanation:
Given
Power 
Distance from the light source 
Intensity is given by
Inserting values
Answer:
the difference is due to resistance tolerance
Explanation:
In mathematical calculations, either done by hand or in a computer program, the heat taken from the resistors is the nominal value, which is the writing in its color code, so all calculations give a result, but the Resistors have a tolerance, indicated by the last band that is generally 5%, 10%, 20% and in the expensive precision resistance can reach 1%.
This tolerance or fluctuation in the resistance value is what gives rise to the difference between the computation values and the values measured with the instruments, multimeters.
Another source of error also occurs due to temperature changes in the circuit that affect the nominal resistance value, there is a very high resistance group that indicates the variation with the temperature, they are only used in critical circuits, due to their high cost
In summary, the difference is due to resistance tolerance.
1. Frequency: 
The frequency of a light wave is given by:
where
is the speed of light
is the wavelength of the wave
In this problem, we have light with wavelength
Substituting into the equation, we find the frequency:
2. Period: 
The period of a wave is equal to the reciprocal of the frequency:
The frequency of this light wave is (found in the previous exercise), so the period is:
Answer:
Correct option a. one state variable T.
Explanation:
In the case of an ideal gas it is shown that internal energy depends exclusively on temperature, since in an ideal gas any interaction between the molecules or atoms that constitute it is neglected, so that internal energy is only kinetic energy, which depends Only of the temperature. This fact is known as Joule's law.
The internal energy variation of an ideal gas (monoatomic or diatomic) between two states A and B is calculated by the expression:
ΔUAB = n × Cv × (TB - TA)
Where n is the number of moles and Cv the molar heat capacity at constant volume. Temperatures must be expressed in Kelvin.
An ideal gas will suffer the same variation in internal energy (ΔUAB) as long as its initial temperature is TA and its final temperature TB, according to Joule's Law, whatever the type of process performed.
The negative charge comes from the electrons.
An ion is negatively charged means it has more number of electrons compared to protons.
Thus, a negatively-charged ion always has more of ELECTRONS.
