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3 years ago

5 characteristics of an Electromagnetic wave

1 answer:

8 0

1. Electromagnetic waves travel with a constant velocity in vacuum . The velocity is approximately 186,000 miles per second or 300, 000 km per sec, the same as the speed of light.

2.Electromagnetic waves are not deflected by electric or magnetic fields

3. Electromagnetic waves can show interference or diffraction

4. Electromagnetic waves are transverse waves, similar to water waves in the ocean or the waves seen on a guitar string.

5. Electromagnetic waves may be polarized.

6. Electromagnetic waves need no medium of propagation.

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Which best describes a material that could be used as a pan for baking cakes?

san4es73 [151]

Answer:

Explanation:

4 0

3 years ago

In a science museum, a 110 kg brass pendulum bob swings at the end of a 13.9 m -long wire. the pendulum is started at exactly 8:

saw5 [17]

The number of oscillations completed by the pendulum is 2736.

The amplitude of the pendulum is 3.47 m.

The given motion is an underdamped motion. So its frequency will be similar to that of a simple harmonic motion.

The frequency of oscillation is defined as the number of oscillations completed in unit time. It is calculated using the formula.

f=(1/2π)*√(l/g)

where f is the frequency, l is the length of the pendulum, and g is the acceleration due to gravity.

Given the length of the wire l=13.9 m and acceleration due to gravity g=9.8 m/s^2. The frequency of oscillation is:

f=(1/(2*3.14)) * √(13.9/9.8)

f=0.19 Hz (approximately)

Since the pendulum started oscillating at 8:00 am, 4 hours has been passed when it shows 12:00 pm. So time t=4 hours or t=4*3600. Hence t=14400 s. The total number of oscillations is then given by the formula,

n=ft

where n is the number of oscillations.

n=0.19*14400=2736.

In damping motion, the amplitude of the pendulum decreases with time. The amplitude of the pendulum is given by the formula,

A' = A exp (-b*t)

where A' is the amplitude after time t, A is the initial amplitude, b is the damping constant, and t is the time.

Here A=1.2 m, b=0.010 kg/s and t=14400 s.

A' = 1.2 exp (-0.010*14400)

A'=3.47 m (approximately)

Learn more about amplitude.

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5 0

2 years ago

At what frequency will a 3.0 Î¼F capacitor have a reactance of 7.0 kÎ©?

blagie [28]

Answer:

Frequency, f = 7.57 Hz

Explanation:

It is given that,

Capacitance, $C=3\ \mu F=3\times 10^{-6}\ F$

Capacitive reactance, $X_C=7\ k\Omega=7\times 10^3\ \Omega$

We need to find the frequency. The capacitive reactance of the capacitor is given by :

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

f is the frequency

$f=\dfrac{1}{2\pi CX_C}$

$f=\dfrac{1}{2\pi \times 3\times 10^{-6}\ F\times 7\times 10^3\ \Omega}$

f = 7.57 Hz

Hence, this is the required solution.

5 0

4 years ago

Suppose the maximum safe intensity of microwaves for human exposure is taken to be 1.00 W/m2 . (a) If a radar unit leaks 10.0 W

storchak [24]

Answer:

We must be approximately at least 1.337 meters away to be exposed to an intensity considered to be safe.

Explanation:

Let suppose that intensity is distributed uniformly in a spherical configuration. By dimensional analysis, we get that intensity is defined by:

$I = \frac{\dot W}{\frac{4\pi}{3}\cdot r^{3}}$ (1)

Where:

$I$ - Intensity, measured in watts per square meter.

$r$ - Radius, measured in meters.

If we know that $\dot W = 10\,W$ and $I = 1\,\frac{W}{m^{2}}$ , then the radius is:

$r^{3} = \frac{\dot W}{\frac{4\pi}{3}\cdot I }$

$r = \sqrt[3]{\frac{3\cdot \dot W}{4\pi\cdot I} }$

$r = \sqrt[3]{\frac{3\cdot (10\,W)}{4\pi\cdot \left(1\,\frac{W}{m^{2}} \right)} }$

$r \approx 1.337\,m$

We must be approximately at least 1.337 meters away to be exposed to an intensity considered to be safe.

5 0

3 years ago

How do you find the weight of an object when given the mass and acceleration?

murzikaleks [220]

Weight of an object is given by the formula W = m x g , where

m : mass of the object

g : gravitational acceleration

It is <u>independent of the horizontal </u><u>acceleration</u>.

<h3>What do we mean by weight of an object?</h3>

Weight is a gauge of how strongly gravity is<u> pulling something down.</u> It is dependent on the object's mass, or how much matter it consists of. It also depends on the <u>object's uniformly distributed</u> downward acceleration caused by gravity.

This equation can be used to express weight:

W = m x g

<h3>What is the difference between weight and mass of an object?</h3>

In everyday speech, the phrases "mass" and "weight" are frequently used interchangeably; nevertheless, the two concepts don't have the same meaning. In contrast to weight, which is a <u>measurement of</u> how the <u>force</u> of gravity works upon a mass, mass is the <u>amount of substance</u> in a material.

To learn more about gravity and acceleration :

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3 0

2 years ago