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3 years ago

Which statement describes the speed of electromagnetic waves?

Physics

2 answers:

goldfiish [28.3K]3 years ago

7 0

Answer:

Their speed in a vacuum is a constant value.

Explanation:

Electromagnetic waves consits of oscillations of electric field and magnetic field. The oscillations of these fields occur in a direction perpendicular to the direction of propagation of the waves, so they are transverse wave. Electromagnetic waves, contrary to mechanical waves, do not need a medium to propagate, so they can also travel through a vacuum. In a vacuum, their speed is constant and has always the same value, the speed of light:

$c=3\cdot 10^8 m/s$

Marianna [84]3 years ago

3 0

Answer:

Their speed in a vacuum is a constant value.

Explanation:

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The Capacitive reactance of a 0.094uF capacitor when a frequency of 25kHz is applied is lus 68 Ohms 0.68 Ohms luf

Nana76 [90]

Answer:

Capacitive reactance of the capacitor is 68 ohms

Explanation:

It is given that,

Capacitance, $C=0.094\ \mu F=0.094\times 10^{-6}\ F$

Frequency, $f=25\ kHz=25\times 10^3\ Hz$

Capacitive reactance is given by :

$X_C=\dfrac{1}{2\pi fC}$

$X_C=\dfrac{1}{2\pi 25\times 10^3\times 0.094\times 10^{-6}}$

$X_C=67.72\ \Omega$

$X_C=68\ \Omega$

So, the capacitive reactance of the capacitor is 68 ohms. Hence, this is the required solution.

8 0

3 years ago

A scientist in central Nebraska is studying factors that affect the formation of tornadoes. How might the scientist benefit from

Deffense [45]

The first one i think

Hope i helped

8 0

3 years ago

Read 2 more answers

Older railroad tracks in the U.S. are made of 12-m-long pieces of steel. When the tracks are laid, gaps are left between section

____ [38]

Answer: ∆L = 0.49cm ≈ 0.50cm

Therefore there should be 0.5 cm gap between each piece of steel.

Explanation:

Thermal expansion of steel is the increase in size of steel as a result of increased temperature. It can be represented by the mathematical expression:

∆L = L(k)∆T .....1

Where;

∆L is the change in length

L is the initial length

∆T is the change in temperature

k is the specific Linear expansion coefficient.

Given;

L = 12m

∆T = 50°C - 16°C = 34°C

k (for steel) = 1.2 × 10^-6 /C

Substituting the values into the equation 1

∆L = 12 × 34 × 12×10^-6

∆L = 4896 × 10^-6 m

∆L = 0.49cm ≈ 0.50cm

Therefore there should be 0.5 cm gap between each piece of steel.

6 0

3 years ago

Read 2 more answers

You are using an 8 th order low-pass filter. Determine the roll-off achievable in the stop band, in dB/dec, and determine the ph

Andreas93 [3]

Answer: The complexity of filter is the order of the filter. Greater the order of the filter, more efficient the filter is. Roll of value of one filter is 20dB/dec. So the roll-off value of 8th order filter is 160dB/dec. 8th order filter is more efficient than the second order low-pass filter.

4 0

4 years ago

A boy whirls a ball on a string in a horizontal circle of radius 0.65 m. If the ball is traveling at 9 m/s, what is the centripe

djverab [1.8K]

Answer:

ac = 124.6 m/s²

Explanation:

When an object executes a uniform circular motion, acceleration is produced in it due to a change in its direction during the motion. This acceleration is called the centripetal acceleration. The formula used to find this acceleration is given as follows:

$a_{c} = \frac{v^{2}}{r}\\$

where,

ac = centripetal acceleration = ?

v = speed = 9 m/s

r = radius = 0.65 m

Therefore,

$a_{c} = \frac{(9\ m/s)^{2}}{0.65\ m}\\$

5 0

3 years ago