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The ratio of contributions made by the e...

The ratio of contributions made by the eletric field and magnetic field components to the intensity of an `EM` wave is.

A

`c : 1`

B

`c^(2) :1`

C

`1 : 1`

D

`sqrt(c) :1`

Text Solution

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The correct Answer is:
To find the ratio of contributions made by the electric field and magnetic field components to the intensity of an electromagnetic (EM) wave, we can follow these steps: ### Step-by-Step Solution: 1. **Understand the Relationship Between Electric and Magnetic Fields**: The electric field amplitude \( E_0 \) and magnetic field amplitude \( B_0 \) in an electromagnetic wave are related by the equation: \[ E_0 = c \cdot B_0 \] where \( c \) is the speed of light. 2. **Calculate Average Energy Density**: The average energy density contributed by the electric field \( U_E \) is given by: \[ U_E = \frac{1}{2} \epsilon_0 E_0^2 \] and the average energy density contributed by the magnetic field \( U_B \) is given by: \[ U_B = \frac{1}{2} \frac{B_0^2}{\mu_0} \] 3. **Substituting the Relationship**: We can substitute \( E_0 = c \cdot B_0 \) into the equation for \( U_E \): \[ U_E = \frac{1}{2} \epsilon_0 (c \cdot B_0)^2 = \frac{1}{2} \epsilon_0 c^2 B_0^2 \] 4. **Using the Speed of Light Relation**: Recall that the speed of light \( c \) can be expressed in terms of \( \epsilon_0 \) and \( \mu_0 \): \[ c = \frac{1}{\sqrt{\mu_0 \epsilon_0}} \implies c^2 = \frac{1}{\mu_0 \epsilon_0} \] Substitute \( c^2 \) into the energy density equation: \[ U_E = \frac{1}{2} \epsilon_0 \left(\frac{1}{\mu_0 \epsilon_0}\right) B_0^2 = \frac{1}{2 \mu_0} B_0^2 \] 5. **Finding the Ratio of Average Energy Densities**: Now we have: - \( U_E = \frac{1}{2 \mu_0} B_0^2 \) - \( U_B = \frac{1}{2} \frac{B_0^2}{\mu_0} \) The ratio of the average energy densities is: \[ \frac{U_E}{U_B} = \frac{\frac{1}{2 \mu_0} B_0^2}{\frac{1}{2} \frac{B_0^2}{\mu_0}} = 1 \] 6. **Conclusion**: Therefore, the ratio of contributions made by the electric field and magnetic field components to the intensity of an EM wave is: \[ 1 : 1 \] ### Final Answer: The ratio of contributions made by the electric field and magnetic field components to the intensity of an EM wave is \( 1 : 1 \).

To find the ratio of contributions made by the electric field and magnetic field components to the intensity of an electromagnetic (EM) wave, we can follow these steps: ### Step-by-Step Solution: 1. **Understand the Relationship Between Electric and Magnetic Fields**: The electric field amplitude \( E_0 \) and magnetic field amplitude \( B_0 \) in an electromagnetic wave are related by the equation: \[ E_0 = c \cdot B_0 ...
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