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3 years ago

What Are domains in magnetism

Physics

1 answer:

masya89 [10]3 years ago

3 0

Groups of atoms that line up to makes something magnetic

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the brakes on a car do 240000j of work in stopping the car. if the car travels a distance of 40m while the brakes re being appli

Tpy6a [65]

A joule is one Newton of force applied over a meter.
For every meter, the brakes put 240000N of force (N=Newtons).
For 40m, multiply the Newtons by 40.
240000N*40=9600000N

3 0

3 years ago

A car horn emits a frequency of 400 Hz. A car traveling at 20.0 m/s sounds the horn as it approaches a stationary pedestrian. Wh

Temka [501]

Answer:

The observed frequency by the pedestrian is 424 Hz.

Explanation:

Given;

frequency of the source, Fs = 400 Hz

speed of the car as it approaches the stationary observer, Vs = 20 m/s

Based on Doppler effect, as the car the approaches the stationary observer, the observed frequency will be higher than the transmitted (source) frequency because of decrease in distance between the car and the observer.

The observed frequency is calculated as;

$F_s = F_o [\frac{v}{v_s + v} ] \\\\$

where;

F₀ is the observed frequency

v is the speed of sound in air = 340 m/s

$F_s = F_o [\frac{v}{v_s + v} ] \\\\400 = F_o [\frac{340}{20 + 340} ] \\\\400 = F_o (0.9444) \\\\F_o = \frac{400}{0.9444} \\\\F_o = 423.55 \ Hz \\$

F₀ ≅ 424 Hz.

Therefore, the observed frequency by the pedestrian is 424 Hz.

8 0

3 years ago

What do we call the minimum energy that is required by an electron to leave the metal target in the photoelectric effect?Select

Sergio [31]

The work function is what we call the minimum energy that is required by an electron to leave the metal target in the photoelectric effect.

6 0

3 years ago

Read 2 more answers

A solenoid of length 2.50 cm and radius 0.750 cm has 25 turns. If the wire of the solenoid has 1.85 amps of current, what is the

vfiekz [6]

Answer:

13.875 T

Explanation:

Parameters given:

Length of solenoid, L = 2.5 cm = 0.025 m

Radius of solenoid, r = 0.75 cm = 0.0075 m

Number of turns, N = 25 turns

Current, I = 1.85 A

Magnetic field, B, is given as:

B = (N*r*I) /L

B = (25 * 0.0075 * 1.85)/0.025

B = 13.875 T

4 0

3 years ago

The microwaves in a certain microwave oven have a wavelength of 12.2 cm. How wide must this oven be so that it will contain five

leva [86]

Answer:

$l = 0.305 \ m$

$f = 3.0*10^{11} \ Hz$

Explanation:

From the question we are told that

The wavelength is $\lambda = 12.2 \ cm = 0.122 \ m$

The number of antinodal planes of the electric field considered is n = 5

The width is mathematically represented as

$l = \frac{ n \lambda}{2}$

$l = \frac{5 * 0.122 }{ 2}$

$l = 0.305 \ m$

Generally the frequency the errors was made is mathematically represented as

$f = \frac{c}{\lamda_k}$

Here c is the speed of light with value $c = 3.0*10^{8} \ m/s$

$\lambda_k$ is the wavelength of the microwave has to be in order for there still to be five antinodal planes of the electric field along the width of the oven, which is mathematically represented as

$\lambda_k = \frac{ \lambda * \frac{0.04}{2} }{n/2}$

$\lambda_k = \frac{0.122*0.02}{5/2}$

$f = \frac{3.0*10^{8}}{0.000976}$

$f = 3.0*10^{11} \ Hz$

8 0

3 years ago