Chapter 13:
Electromagnetic Waves
Practice Test
1.
Infrared waves with a frequency of 1 × 10
13
Hz have a wavelength of 3 × 10
-5
m. Express this wavelength as a decimal number.
a.
300 m
b.
0.00003 m
c.
0.000000003 m
d.
300,000 m
Hint
2.
An AM radio station broadcasts at a frequency of 620 kHz. Express this frequency in Hz using scientific notation.
a.
6.2 × 10
-5
Hz
b.
6.2 × 10
2
Hz
c.
620 × 10
3
Hz
d.
6.2 × 10
5
Hz
Hint
3.
Radio waves with a frequency of 125,000 Hz have a wavelength of 1.84 km when traveling in ice. What is the speed of the radio waves in ice?
a.
3.0 × 10
5
km/s
b.
6.79 × 10
4
km/s
c.
2.30 × 10
5
km/s
d.
1.47 × 10
-5
km/s
Hint
4.
An electromagnetic wave has a wavelength of 0.054 m. What is the wavelength in scientific notation?
a.
5.4 × 10
-3
m
b.
5.4 × 10
-2
m
c.
54 × 10
-3
m
d.
5.4 × 10
2
m
Hint
5.
An FM radio station broadcasts at a frequency of 101 MHz. Express this frequency in Hz using scientific notation.
a.
1.01 × 10
-8
Hz
b.
1.01 × 10
2
Hz
c.
1.01 × 10
8
Hz
d.
1.01 × 10
5
Hz
Hint
6.
Express the number 20,000 in scientific notation.
a.
20 × 10
3
b.
2 × 10
4
c.
2 × 10
-4
d.
2 × 10
3
Hint
7.
Earth is about 4,500,000,000 years old. Express this number in scientific notation.
a.
4.5 × 10
-8
b.
4.5 × 10
-9
c.
4.5 × 10
9
d.
4.5 × 10
8
Hint
8.
The speed of electromagnetic waves in air is 300,000 km/s. What is the frequency of electromagnetic waves that have a wavelength of 5 × 10
-3
km?
a.
1.5 × 10
3
Hz
b.
6 × 10
7
Hz
c.
1.5 × 10
6
Hz
d.
6 × 10
10
Hz
Hint
9.
The speed of radio waves in water is about 2.26 × 10
5
km/s. What is the frequency of radio waves that have a wavelength of 3.0 km?
a.
6.8 × 10
5
Hz
b.
6.8 × 10
-5
Hz
c.
7.5 × 10
-4
Hz
d.
7.5 × 10
4
Hz
Hint
10.
Some infrared waves have a frequency of 10,000,000,000,000 Hz. Express this frequency in scientific notation.
a.
1 × 10
13
Hz
b.
1 × 10
10
Hz
c.
10 × 10
9
Hz
d.
10 × 10
12
Hz
Hint
