NEET Electromagnetic Waves — Set 5

Question 1

An electromagnetic wave in vacuum has a frequency of $ 30 \, \text{MHz} $. What is its wavelength? (Given $ c = 3 \times 10^8 \, \text{m/s} $)

Accepted Answer

Using $ v \lambda = c $, we have $ \lambda = \frac{c}{v} = \frac{3 \times 10^8}{30 \times 10^6} = 10 \, \text{m} $.

Question 2

In electromagnetic wave theory, what is the relationship between the electric and magnetic field amplitudes in vacuum?

Accepted Answer

The electric and magnetic field amplitudes are related by the speed of light in vacuum, where $ E_0 = B_0 c $, or equivalently $ B_0 = \frac{E_0}{c} $, ensuring energy balance in the wave.

Question 3

Infrared waves are often called heat waves because:

Accepted Answer

Infrared waves are absorbed by water molecules in materials, increasing their thermal motion and thus heating the material.

NEET Physics: Electromagnetic Waves — Practice Set 5

Q1. An electromagnetic wave in vacuum has a frequency of \( 30 \, \text{MHz} \). What is its wavelength? (Given \( c = 3 \times 10^8 \, \text{m/s} \))

Q2. In electromagnetic wave theory, what is the relationship between the electric and magnetic field amplitudes in vacuum?

Q3. Infrared waves are often called heat waves because:

Q4. The velocity of light in a medium with permittivity \( \varepsilon \) and permeability \( \mu \) is:

Q5. What is one precaution welders take to protect their eyes from UV radiation?

Q6. An electromagnetic wave has a wave number \( k = 0.5 \, \text{rad/m} \). What is its wavelength in vacuum?

Q7. Which electromagnetic waves are produced by the vibration of atoms and molecules?

Q8. What significant prediction emerged from Maxwell's equations regarding wave propagation?

Q9. What is the significance of Maxwell's displacement current in the context of electromagnetic waves?

Q10. What property of infrared waves makes them suitable for physical therapy applications?