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2 years ago

An electromagnetic wave has a frequency of 4.0 x 1018 Hz. What is the

Physics

1 answer:

trapecia [35]2 years ago

8 0

Answer: D

Wavelength λ = 7.5 × 10^-11 m

Explanation:

You are given the frequency of an electromagnetic wave to be:

F = 4.0 x 1018 Hz. And the speed of light C to be

C = 3 × 10^8 m/s

From wave speed formula:

Wave speed is the product of waves frequency and wavelength. That is,

V = fλ

Where

f = frequency

λ = wavelength

V = C = speed of light

Substitute the values of the parameters into the formula

C = fλ

3 × 10^8 = 4 × 10^18 × λ

Make λ the subject of formula

λ = (3×10^8)/(4×10^18)

λ = 7.5 × 10^-11 m

Therefore, the wavelength of the wave is 7.5 × 10^-11 m

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A combination of two or more simple machines is a (n)

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A compound Machine is 2 machines that work together in order to make a task easier.

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2 years ago

A uniform horizontal rod of mass Mand length rotates with angular velocity about a vertical axis through its center. Attached to

Lostsunrise [7]

Answer:

Explanation:

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2 years ago

10. A hockey puck with mass 0.3 kg is sliding along ice that can be considered frictionless. The puck’s velocity is 20 m/s when

SVEN [57.7K]

Answer:

$d = \frac{v^2_i}{2a}= \frac{(20m/s)^2}{2* 3.43 m/s^2}=58.309m$

Explanation:

For this case we can use the second law of Newton given by:

$\sum F = ma$

The friction force on this case is defined as :

$F_f = \mu_k N = \mu_k mg$

Where N represent the normal force, $\mu_k$ the kinetic friction coeffient and a the acceleration.

For this case we can assume that the only force is the friction force and we have:

$F_f = ma$

Replacing the friction force we got:

$\mu_k mg = ma$

We can cancel the mass and we have:

$a = \mu_k g = 0.35 *9.8 \frac{m}{s^2}= 3.43 \frac{m}{s^2}$

And now we can use the following kinematic formula in order to find the distance travelled:

$v^2_f = v^2_i - 2ad$

Assuming the final velocity is 0 we can find the distance like this:

$d = \frac{v^2_i}{2a}= \frac{(20m/s)^2}{2* 3.43 m/s^2}=58.309m$

5 0

3 years ago

Describe an application where a parallel circuit might work better than a series circuit

babunello [35]

In rooms where there are multiple lights, a parallel circuit is better.

In a series circuit, if one light broke, all of the lights would turn off, as the circuit would be broken.

However, in parallel, if one bulb broke, the circuit could still be complete through the other bulbs, so they will stay on.

7 0

3 years ago

A 0.900-V potential difference is maintained across a 1.5m length of 2

Daniel [21]

Answer:

I = 6.42 A

Explanation:

Given that,

Potential difference, V = 0.9 V

Length of the wire, l = 1.5 m

Area of cross section, $A=0.6\ mm^2=6\times 10^{-7}\ m^2$

We need to find the current in the wire. Let I is current. We can find it using Ohm's law as follows :

V = IR

Where R is the resistance of the wire

$I=\dfrac{V}{R}\\\\I=\dfrac{V}{\rho \dfrac{l}{A}}\\\\I=\dfrac{0.9}{5.6\times 10^{-8}\times \dfrac{1.5}{6\times 10^{-7}}}\\\\I=6.42\ A$

So, the current in the wire is 6.42 A.

3 0

3 years ago