Question

The rms value of the electric field of the light coming from the sun is $720N/C$. The average total energy density of the electromagnetic wave is:
$\left(A\right)3.3\times {10}^{-3}J/m^3$
$\left(B\right)4.5810\times {10}^{-6}J/m^3$
$\left(C\right)6.3710\times {10}^{-9}J/m^3$
$\left(D\right)81.3510\times {10}^{-12}J/m^3$

Answer 1

Hint: Electrification is the process of adding charge to the body. The property of the matter that produces and experiences electrical and magnetic fields is called charge. Using the above the statement determines the SI unit of charge. Then determine the energy density by finding the RMS value of the electric field.

Formula used:
$E={\epsilon }_0{E}_{RMS}^2$
Where $E$ is the energy density, $E_{RMS}$ is the RMS value of the electric field.

Complete step by step answer:
The study of phenomena exhibited by electric charges at rest is called electrostatics.
The property of the matter that produces and experiences electrical and magnetic fields is called charge. Voltage is the product of current and resistance.
Electrification is the process of adding charge to the body.
The property of the matter that produces and experiences electrical and magnetic fields is called charge.
Electric field is static. If the electric field is a variable, then it has a magnetic field and then it is an electromagnetic field. The static electric field dissipates no power.
Root mean square is represented as RMS value. RMS value can be defined as the field that provides the same dissipation power.
We can also say it as the square root of the arithmetic mean of the square of the values. The electric field refers to the RMS value of the electric field. Its SI unit is volts per meter.
The RMS value of the electric field is $720N/C.$
The energy density is given by
$E={\epsilon }_0{E}_{RMS}^2$
$\Rightarrow E=8.85\times {10}^{-12}\times {\left(720\right)}^2$
$\Rightarrow E=4.58\times {10}^{-6}J/m^3$

Hence option B is the correct option.

Note: The direction of flow of flow of current is from positive terminal to negative terminal of the cell. Silver and copper are good conductors.
Voltmeter is connected in series with the device. Voltage causes the current to flow. The standard unit for expression of voltage is volt. It is represented by the symbol $v$. Voltage depends on current and resistance.