NEET Electromagnetic Waves — Set 8

Question 1

What is the approximate wavelength range of gamma rays as per the document?

Accepted Answer

The document states that gamma rays have wavelengths from about $ 10^{-10} \, \text{m} $ to less than $ 10^{-14} \, \text{m} $.

Question 2

In the context of electromagnetic theory, what fundamental principle explains why a changing electric field can generate a magnetic field?

Accepted Answer

The Ampere-Maxwell law states that a changing electric field (via displacement current) acts as a source of a magnetic field, complementing the conduction current's role in generating magnetic fields.

Question 3

Who first experimentally demonstrated the existence of electromagnetic waves?

Accepted Answer

Heinrich Rudolf Hertz, in 1887, was the first to produce and detect electromagnetic waves, verifying Maxwell's predictions.

NEET Physics: Electromagnetic Waves — Practice Set 8

Q1. What is the approximate wavelength range of gamma rays as per the document?

Q2. In the context of electromagnetic theory, what fundamental principle explains why a changing electric field can generate a magnetic field?

Q3. Who first experimentally demonstrated the existence of electromagnetic waves?

Q4. Gamma rays are used in medicine primarily for what purpose?

Q5. Why are microwaves used in speed guns to time fast-moving objects?

Q6. An electromagnetic wave in vacuum has a frequency of \( 75 \, \text{MHz} \). What is its wavelength? (Given \( c = 3 \times 10^8 \, \text{m/s} \))

Q7. What is a common method to detect visible light as per the document?

Q8. In an electromagnetic wave, if the electric field oscillates along the \( y \)-axis and the wave propagates along the \( x \)-axis, what is the direction of the magnetic field?

Q9. What physical principle explains why electromagnetic waves can carry energy over long distances?

Q10. A capacitor in a circuit has a conduction current of \( 2.5 \, \text{A} \) in the wires. What is the displacement current between the plates?