This question is about waves in the electromagnetic (e.m.) spectrum - Edexcel - GCSE Physics: Combined Science - Question 6 - 2022 - Paper 1

To calculate the wavelength, we use the formula:

ext{Wavelength} ( ext{λ}) = rac{ ext{Velocity of light} (v)}{ ext{Frequency} (f)}

Substituting the values, we have:

ext{λ} = rac{3.00 imes 10^8 ext{ m/s}}{2.45 imes 10^9 ext{ Hz}} \\ ext{λ} ext{ = } 0.122 ext{ m}

Thus, the wavelength of the microwaves is 0.122 m.

To find the total energy supplied to the oven, we use the efficiency formula:

ext{Efficiency} = rac{ ext{Useful energy output}}{ ext{Total energy input}} imes 100 a$$ Rearranging gives:

ext{Total energy input} = rac{	ext{Useful energy output}}{	ext{Efficiency}}

$$Substituting the values, we have:$$

ext{Total energy input} = rac{42,000 	ext{ J}}{0.55} \\ 	ext{Total energy input} = 76,364 	ext{ J}

$$Therefore, the total amount of energy that must be supplied to the oven is approximately 76,364 J.$$

X-rays and radio waves encompass a range of applications and characteristics:

Uses of Both Types of Radiation

• X-rays are commonly used in medical diagnostics, such as detecting broken bones, examining the lungs, and in radiotherapy for cancer treatment.
• Radio waves are utilized in broadcasting (e.g., radio and television), communications, and in other technologies like radar.

Differences in Electron Involvement

• X-rays are produced when electrons in an atom absorb energy and transition to a higher energy level. When they fall back, they emit high-energy radiation, which is ionizing and has significant applications in medicine.
• Radio waves, on the other hand, are generated by alternating current in circuits, where electrons oscillate and create electromagnetic waves with lower energy, thus non-ionizing.

In summary, while both are vital parts of the electromagnetic spectrum, they differ significantly in energy levels, production methods, and applications.