What's the answer? and is my answer correct?

Anyone know this... pls help its for a grade

hodyreva [135]

His average speed is 45 miles an hour

3 0

3 years ago

Un diapasón vibra a 140 [Hz] y la onda emitida por él se propaga con una rapidez de 340 m/s.Considerando lo anterior, se puede a

Gnom [1K]

The question is: A tuning fork vibrates at 140 [Hz] and the wave emitted by it propagates with a speed of 340 m / s. Considering the above, it can be correctly stated that the wavelength of the wave emitted by the tuning fork is

Answer: Wavelength of the wave emitted by the tuning fork is 2.43 m.

Explanation:

Given: Frequency = 140 Hz

Speed = 340 m/s

wavelength = ?

Formula used to calculate the wavelength is as follows.

$\lambda = \frac{v}{f}$

where,

$\lambda$ = wavelength

v = speed

f = frequency

Substitute the values into above formula.

$\lambda = \frac{v}{f}\\= \frac{340 m/s}{140 Hz} (1 Hz = 1 s^{-1})\\= 2.43 m$

Thus, we can conclude that wavelength of the wave emitted by the tuning fork is 2.43 m.

5 0

3 years ago

The intensity of electromagnetic waves from the sun is 1.4 kW/m2 just above the earth's atmosphere. Eighty percent of this reach

Lina20 [59]

Answer:

4.7 × 10⁵J

Explanation:

E = I * a * t

80% = 0.80

25cm = 0.25m

52cm = 0.52m

0.90h = 3240s

E = (0.80)(1400)(0.25 * 0.52)(3240)

= 4.7 * 10⁵J

3 0

4 years ago

An electron having 500ev energy enters at right angle to a uniform magnetic field of 10^-4 Tesla. If its specific charge is 1.75

gtnhenbr [62]

Answer:

The correct answer might be $r = 2.8^{27}$ meters.

Explanation:

<u>The Answer Given might not be correct, I just did what my brain said.</u>

As the angle is perpendicular so Θ=90.

Putting this in the equation to calculate the magnetic force as:

F = evBsinΘ

F= evBsin90 *sin90 = 1 so,

F= evB.

Now when the electron will start to move in a circle, The necessary force that makes the electron rotate in a circle is given by Centripetal force.

So,

Magneteic Force = Centripetal Force

evB = $\frac{mv^{2} }{r}$

r = $\frac{mv}{Be}$ ......(1)

Now the problem is, We don't know " v " so we need to calculate velocity first,

Calculation of Velocity:

In order to calculate the velocity of electron, We should know the potiential difference with which the electrons are accelerated which in our case is 500ev. If "V" is the potiential difference, the energy gained by electrons during accelreation will be Ve. This appear as kinectic enrgy of electrons as,

K.E = Ve

$\frac{1}{2}$ m $v^{2}$ = Ve