Ask question

Ask question

All categories

2 years ago

5

A quarter-wave monopole radio antenna (also called a Marconi antenna) consists of a long conductor of one quarter the length of

the transmitted wavelength. The lower end of the antenna is connected to a conducting ground plane (often simply the Earth) which reflects the transmitted signal, creating an effective antenna length of a half wavelength. (a) What must be the height of the antenna (in m) for a radio station broadcasting at 514 kHz

1 answer:

alexandr402 [8]2 years ago

3 0

Answer:

145.91 m

Explanation:

Data provided in the the question:

Wavelength of radio wave, $\lambda = \frac c f$

Here, c is speed of radio wave in air = 3 × 10⁸ m/s

f is the frequency = 514 kHz = 514 × 10³ Hz

Thus,

Wavelength = (3 × 10⁸) ÷ (514 × 10³) m

or

Wavelength = 583.65 m

Thus,

The height of the antenna will be

= $\frac \lambda 4$ = 583.65 ÷ 4 m

= 145.91 m

You might be interested in

A 100-W (watt) light bulb has resistance R=143Ω (ohms) when attached to household current, where voltage varies as V=V0sin(2πft)

Phantasy [73]

Complete Question

A 100-W (watt) light bulb has resistance R=143Ω (ohms) when attached to household current, where voltage varies as V=V0sin(2πft), where V0=110 V, f=60 Hz. The power supplied to the bulb is P=V2R J/s (joules per second) and the total energy expended over a time period [0,T] (in seconds) is $U = \int\limits^T_0 {P(t)} \, dt$

Compute U if the bulb remains on for 5h

Answer:

The value is $U = 7.563 *10^{5} \ J$

Explanation:

From the question we are told that

The power rating of the bulb is $P = 100 \ W$

The resistance is $R = 143 \ \Omega$

The voltage is $V = V_o sin [2 \pi ft]$

The energy expanded is $U = \int\limits^T_0 {P(t)} \, dt$

The voltage $V_o = 110 \ V$

The frequency is $f = 60 \ Hz$

The time considered is $t = 5 \ h = 18000 \ s$

Generally power is mathematically represented as

$P = \frac{V^2}{ R}$

=> $P = \frac{( 110 sin [2 \pi * 60t])^2}{ 144}$

=> $P = \frac{ 110^2 [ sin [120 \pi t])^2}{ 144}$

So

$U = \int\limits^T_0 { \frac{ 110^2* [sin [120 \pi t])^2}{ 144}} \, dt$

=> $U = \frac{110^2}{144} \int\limits^T_0 { ( sin^2 [120 \pi t]} \, dt$

=> $U = \frac{110^2}{144} \int\limits^T_0 { \frac{1 - cos 2 (120\pi t)}{2} } \, dt$

=> $U = \frac{110^2}{144} \int\limits^T_0 { \frac{1 - cos 240 \pi t)}{2} } \, dt$

=> $U = \frac{110^2}{144} [\frac{t}{2} - [\frac{1}{2} * \frac{sin(240 \pi t)}{240 \pi} ] ]\left | T} \atop {0}} \right.$

=> $U = \frac{110^2}{144} [\frac{t}{2} - [\frac{1}{2} * \frac{sin(240 \pi t)}{240 \pi} ] ]\left | 18000} \atop {0}} \right.$

$U = \frac{110^2}{144} [\frac{18000}{2} - [\frac{1}{2} * \frac{sin(240 \pi (18000))}{240 \pi} ] ]$

=> $U = 7.563 *10^{5} \ J$

7 0

2 years ago

What do you mean by kinetic energy and potential energy ?

Verizon [17]

Kinetic Energy of an object is the measure of the work an object can do by virtue of its motions..

Formula - KE = 1/2 mv^2

Where KE is the kinetic energy, m is the body’s mass, and v is the body’s velocity.

Potential energy is the stored energy in any object or system by virtue of its position or arrangement of parts..

Formula - W = mgh

Where,

. m is the mass in kilograms

. g is the acceleration due to gravity

. h is the height in meters

Hope it helpz~ uh..

4 0

1 year ago

According to the law of conservation of energy, which statement must be

alina1380 [7]

Answer: THE ANSWER IS C!

The total energy of a system can decrease only if energy leaves the system.

Explanation: Apex!

7 0

2 years ago

Describe what it means if a chemical or physical property is periodic

vesna_86 [32]

It means that you consider the elements as a list organized by atomic number, the property is seen to repeat over and over as you move through that list.

6 0

2 years ago

if the amplitude of sine curve is 4 and the frequency is 1 with no phase shift, what is the function that descirbes this curve?

Vlada [557]

Answer:

y = 4 Sin (2πt)

Explanation:

Amplitude, A = 4

frequency, f = 1

Wave function is given by

y = A sinωt

where, ω is angular frequency

ω = 2 π f = 2 π x 1 = 2π

So, the desired wave function

y = 4 Sin (2πt)

8 0

2 years ago