$$4.5 \times 10$$^{-5}$$ \text{ m}$

Question 1

Which of the following is the correct SI unit for measuring frequency?

Accepted Answer

$$	ext{Hz} ($$Hertz)

Question 2

A radio wave has a frequency of $$2 	imes 10^6$ Hz. What is the correct way to express this frequency using SI prefixes?

Accepted Answer

$$2$$ MHz

Question 3

A student measures a time interval as $$3.5$$ hours. Convert this time into seconds using standard form.

Accepted Answer

$$1.26 	imes 10^4$ 	ext{ s}$

Question 4

Which of the following best describes what happens to a wave when it passes from air into glass?

Accepted Answer

The wave slows down and changes direction due to refraction.

Question 5

A practical investigation is set up to measure the speed of a wave in a metal rod. Which equipment would be most suitable?

Accepted Answer

A signal generator and an oscilloscope.

Question 6

Which equation correctly relates the speed ($$v$$), frequency ($$f$$), and wavelength ($$\lambda) of a $$wave?

Accepted Answer

$$v = f \lambda$$

Question 7

Which electromagnetic wave is most likely to cause skin cancer due to its effect on cells?

Accepted Answer

Ultraviolet

Question 8

Which statement about electromagnetic waves is correct?

Accepted Answer

All electromagnetic waves are transverse and travel at the same speed in a vacuum.

Question 9

Which of the following is a correct grouping of the electromagnetic spectrum in order of increasing frequency?

Accepted Answer

Radio waves, microwaves, infrared, visible, ultraviolet, x-rays, gamma rays

Question 10

Why are gamma rays more dangerous than radio waves?

Accepted Answer

Gamma rays have higher frequency and can cause mutations in cells.

Question 11

Which of the following is NOT a use of radio waves?

Accepted Answer

Cooking food

Question 12

A light wave passes from air into water. What happens to its speed and direction?

Accepted Answer

The speed decreases and the wave bends towards the normal.

Question 13

Which of the following best explains why our eyes can only detect a limited range of electromagnetic radiation?

Accepted Answer

The photoreceptors in our eyes are sensitive only to visible light frequencies.

Question 14

Which of the following is a correct statement about the effect of different substances on electromagnetic waves?

Accepted Answer

Different substances may absorb, transmit, or reflect electromagnetic waves in ways that vary with wavelength.

Question 15

A student uses a ruler and a stopwatch to measure the speed of a wave in water. Which formula should they use?

Accepted Answer

$$v = \frac{d}{t}$$

Question 16

Which electromagnetic wave is used for thermal imaging and short-range communications?

Accepted Answer

Infrared

Question 17

Which of the following is a correct statement about the dangers of electromagnetic waves?

Accepted Answer

The potential danger increases with increasing frequency.

Question 18

Which electromagnetic wave is most likely to cause internal heating of body cells?

Accepted Answer

Microwaves

Question 19

Which of the following can be produced by, or can themselves induce, oscillations in electrical circuits?

Accepted Answer

Radio waves

Question 20

A student records a measurement as $$0.000045$$ meters. Express this value in standard form using the correct number of significant figures.

Accepted Answer

$$4.5 	imes 10$$^{-5}$$ 	ext{ m}$

Waves and the Electromagnetic Spectrum: Key Concepts and Applications

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