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zzz [600]
2 years ago
5

What is the frequency of 20 mm microwaves? A) 100 MHz B) 400 MHz C) 15 GHz D) 73 GHz E) 98 GHz

Physics
1 answer:
Lera25 [3.4K]2 years ago
3 0

Answer:

Explanation:

Given wavelength  = 20 mm = 20 x 10⁻³ m

The microwaves are electromagnetic waves so their velocity will be equal to

3 x 10⁸ m /s.

Now frequency of microwave = velocity / wavelength

= 3 x 10⁸ / 20 x 10⁻³ = 1.5 x 10¹⁰ = 15 x 10⁹ = 15 GHz.

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There is an electromagnetic wave traveling in the -z direction in a standard right-handed coordinate system. What is the directi
wlad13 [49]

Answer: The direction of the electric field, E→, is pointed in the +y direction.

Explanation:

One can use the right hand rule to illustrate the direction of travel of an electromagnetic and thereby get the directions of the electric field, magnetic field and direction of travel of the wave.

The right hand rule states that the direction of the thumb indicate the direction of travel of the electromagnetic wave (<em>in this case the -z direction</em>) and the curling of the fingers point in the direction of the magnetic field  B→ (<em>in this case the +x direction</em>), therefore, the electric field direction E→ is in the direction of the fingers which would be pointed towards the +y direction.

6 0
2 years ago
The boom hoisting sheave must have pitch diameters of no less than _______times the nominal diameter of the rope used.
alexira [117]

Answer:

18 times

Explanation:

According to the security purposes which is set under the rules and regulation OSHA, which describes all the rights to the worker.

In the boom hoist receiving system all the sheaves which are used should have a pitch diameter of rope not less than 18 times the diameter of the nominal rope which is used.

7 0
2 years ago
A thick steel sheet of area 100 in.2 is exposed to air near the ocean. After a one-year period it was found to experience a weig
vladimir1956 [14]

Answer:

Therefore the rate of corrosion 37.4 mpy and 0.952 mm/yr.

Explanation:

The corrosion rate is the rate of material remove.The formula for calculating CPR or corrosion penetration rate is

CPR=\frac{KW}{DAT}

K= constant depends on the system of units used.

W= weight =485 g

D= density =7.9 g/cm³

A = exposed specimen area =100 in² =6.452 cm²

K=534 to give CPR in mpy

K=87.6  to give CPR in mm/yr

mpy

CPR=\frac{KW}{DAT}

        =\frac{534\times( 485g)\times( 10^3mg/g)}{(7.9g/cm^3) \times (100in^2)\times (24h/day)\times (365day/yr)\times 1yr}

        =37.4mpy

mm/yr

CPR=\frac{KW}{DAT}

        =\frac{87.6\times (485g)\times (10^3 mg/g)}{(7.9g/cm^3)\times (100in^2)\times(2.54cm/in)^2\times (24h/day)\times (365day/yr)\times 1yr}

       =0.952 mm/yr

Therefore the rate of corrosion 37.4 mpy and 0.952 mm/yr.

3 0
2 years ago
A rocket train car that is 30 m long is traveling from Los Angeles to New York at v=0.5c when a light at the center of the car f
Nataly [62]

Answer: The reference frame of a passenger in a seat near the center of the train

Explanation:

the speed of light is the same for the passenger and the bicyclist

then the avents are simultaneous fo the passenger not for the bicyclist

the delay between the two events for the bicyclist is

Δt=Δd/vs

where

Δd= lenght of train

vs=speed of sound

the reference frame of a passenger in a seat near the center of the train

Solution:

The space and time transformations are:

x' = γ(x - vt)

t' = γ(t - vx/c²).

In the primed frame the two events are simultaneous, so that Δt' = 0. Also here Δx' = 30. In the unprimed frame Δx' = 30 = γ(Δx - v Δt).......(*)

We also have Δt' = 0 = γ(Δt - vΔx/c²)→Δx = c²Δt/v......(**)

Substituting (**) in (*): 30 = γ(c²Δt/v - vΔt))→Δt = 30/(c²/v - v) =

30/(2c - 0.5c) = 6.7 x 10^(-8)s

5 0
2 years ago
A city uses a water tower to store water for times of high demand. When demand is light, water is pumped into the tower. When de
love history [14]

Answer:

The height of the tower will be 35.714 m

Explanation:

We have given gauge pressure P=350kPa=350\times 10^3Pa

Density of water \rho =1000kg/m^3

We have to find the height of the tower h

We know that gauge pressure is given by P=\rho gh

350\times 10^3=100 0\times 9.8\times h

h=35.714m

So the height of the tower will be 35.714 m

6 0
2 years ago
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