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LenaWriter [7]
2 years ago
9

Which type of electromagnetic radiation is commonly used for long-distance communications?

Physics
1 answer:
Citrus2011 [14]2 years ago
5 0

Answer:

B. Radio waves

Explanation:

Radio waves are transmitted easily through air. They do not cause damage if absorbed by the human body, and they can be reflected to change their direction. These properties make them ideal for communications.

Hope this helps!!

You might be interested in
What is the speed of sound at sea level?
svetlana [45]
The speed of sound at sea level is 340.29 m/s (meters per seconds).
7 0
3 years ago
Find the force necessary to pull a 6 kg object 3 m/s2
mars1129 [50]

Answer:

<h2>18 N</h2>

Explanation:

The force acting on an object given it's mass and acceleration can be found by using the formula

force = mass × acceleration

From the question we have

force = 6 × 3

We have the final answer as

<h3>18 N</h3>

Hope this helps you

6 0
3 years ago
A battery charger can produce 3A at 12 Volt and charges a battery fer 2 hr. Calculate work in KJ.
Oksi-84 [34.3K]

Answer: 259.2 KJ

Explanation:

The formula calculate work don in a circuit is given by :-

W=QV, where Q is charge and V is the potential difference.

The formula to calculate charge in circuit :-

Q=It, where I is current and t is time.

Given : Current : I=3A

Potential difference : V=12\ V

Time : t=2\ hr=2(3600)\text{ seconds}=7200\text{ seconds}

Now, Q=3(7200)=21,600\ C

Then,  W=(21600)(12)=259,200\text{ Joules}=259.2\text{ KJ}

Hence, the work done = 259.2 KJ

4 0
3 years ago
Convert the following to relative uncertainties <br>a) 2.70 ± 0.05cm<br>b) 12.02 ± 0.08cm
DENIUS [597]

data which is expressed in form of following way

a = a_o + \Delta a

here in above expression

a_o = true value

\Delta a = uncertainty in the value

now the relative uncertainty is given as

\frac{\Delta a}{a_o}

now by above formula we can say

a) 2.70 ± 0.05cm

here

True value = 2.70

uncertainty = 0.05

Relative uncertainty = \frac{0.05}{2.70} = 0.0185

b) 12.02 ± 0.08cm

here

True value = 12.02

uncertainty = 0.08

Relative uncertainty = \frac{0.08}{12.02} = 0.00665

4 0
3 years ago
A stone is thrown horizontally with an initial speed of 10 m/s from the edge of a cliff. A stopwatch measures the stone's trajec
olga2289 [7]

Answer:

The height of the cliff is 90.60 meters.

Explanation:

It is given that,

Initial horizontal speed of the stone, u = 10 m/s

Initial vertical speed of the stone, u' = 0 (as there is no motion in vertical direction)

The time taken by the stone from the top of the cliff to the bottom to be 4.3 s, t = 4.3 s

Let h is the height of the cliff. Using the second equation of motion in vertical direction to find it. It is given by :

h=u't+\dfrac{1}{2}gt^2

h=\dfrac{1}{2}gt^2

h=\dfrac{1}{2}\times 9.8\times (4.3)^2

h = 90.60 meters

So, the height of the cliff is 90.60 meters. Hence, this is the required solution.

5 0
3 years ago
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