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3 years ago

What can increase the peak emf in an ac generator without changing the frequency?

Physics

1 answer:

STatiana [176]3 years ago

8 0

Explanation:

The peak emf in an AC generator is given by :

$\epsilon=NAB\omega$

Here,

N is number of turns in the generator

A is area of the coils

B is magnetic field

$\omega$ is angular frequency

It is clear that the peak emf in an ac generator depends on :

The number of turns in the generator
Area of coils
Magnetic field

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Help with the two questions above? Correct answers?

LenKa [72]

(6) first choice: the frequency appears higher and wavelength is shorter.

The car approaches a stationary observer and so the sound will appear to have shorter wavelength. This creates an effect of its siren to sound with higher frequency than it would do if both were stationary.

(7) The Doppler formula for frequency in the case of a stationary observer and source approaching it is as follows:

$f_O = \frac{v}{v-v_s}\cdot f= \frac{343\frac{m}{s}}{(343-25)\frac{m}{s}}\cdot 400Hz \approx 431Hz$

The wavelength is then

$\lambda = \frac{343\frac{m}{s}}{431Hz}\approx 0.80 m$

The third choice "0.80m; 431Hz" is correct

7 0

3 years ago

You read in a science magazine that on the Moon, the speed of a shell leaving the barrel of a modern tank is enough to put the s

olga_2 [115]

To solve this problem we will use the definition of the kinematic equations of centrifugal motion, using the constants of the gravitational acceleration of the moon and the radius of this star.

Centrifugal acceleration is determined by

$a_c = \frac{v^2}{r}$

Where,

v = Velocity

r = Radius

From the given data of the moon we know that gravity there is equivalent to

$a = 1.62m/s$

While the radius of the moon is given by

$r = 1.74*10^6m$

If we rearrange the function to find the speed we will have to

$v = \sqrt{ar}$

$v = \sqrt{1.6(1.74*10^6)}$

$v = 1.7km/s$

The speed for this to happen is 1.7km/s

3 0

3 years ago

What is the wavelength of a sound wave with a frequency of 770 Hz if it speed is 290 m/s?

Studentka2010 [4]

The wavelength of sound wave with frequency 770 Hz and speed of 290 m/s is equal to 0.3767 m

<h3>Explanation:</h3>

The wave equation determining the relationship between speed, frequency and wavelength of a sound wave is given by:

<u>Speed of sound = Frequency of sound × Wavelength of sound wave</u>

v = n × λ .................................(1)

Given:

v = Speed of sound wave = 290 m/s

n = Frequency of sound = 770 Hz

λ = Wavelength = ?

From (1)

v = n × λ

Rewriting the equation for λ, we get

λ = $\frac{v}{n}$

Substituting the values of v and n, we get

λ = $\frac{v}{n} =\frac{290}{770} = 0.3767 \ m$

Hence, the wavelength of sound wave is equal to 0.3767 m

7 0

3 years ago

If you are watching TV programs from 3::50AM-5:30AM for how much hour you are watching

Triss [41]

Answer:

1 hour and 40 mins

Explanation:

6 0

3 years ago

Read 2 more answers

The magnitude of the magnetic field B a distance r from a long straight wire is B = μ 0 I 2 π r where μ 0 is the permeability co

PSYCHO15rus [73]

Answer:

The magnetic field is lowest for largest distance and highest when distance is least.

Explanation:

The magnitude of magnetic field strength at a distance 'r' from a long straight wire carrying current 'I' is given as:

$B=\frac{\mu_0 I}{2\pi r}\\Where,\mu_0\to permeability\ constant\ of\ free\ space$

Now, as per question, the distance 'r' is varied while keeping the current constant in the wire.

As seen from the above formula, the magnitude of magnetic field strength for a constant current varies inversely with the distance 'r'. This means that, as the value of 'r' increases, the magnitude of magnetic field strength decreases and vice-versa.

Therefore, the magnitude of magnetic field strength is maximum when the distance 'r' is least and the magnetic field is minimum for the largest distance.

Example:

If $B_1, B_2,\ and\ B_3$ are the magnitudes of magnetic field strengths for distances $r_1,r_2, \ and\ r_3$ respectively such that $r_1$ . Now, as per the explanation above, the order of magnitudes of magnetic field strength is:

$B_1>B_2>B_3$

6 0

4 years ago