You approach a railroad crossing with a cross buck sign that has no lights or gates. What should you do?

Yellow light of wavelength 590 nm passes through a diffraction grating and makes an interference pattern on a screen 80 cm away.

riadik2000 [5.3K]

Answer:B

Explanation:

Given

Wavelength of light $\lambda =590\ nm$

Screen distance $L=80\ cm$

First fringe is at a distance $y_1=1.9\ cm$

No of lines per mm is given by N

$N=\frac{1}{d}$

where d=slit width

From N-slits Experiment

$\sin \theta _m=\frac{m\lambda }{d}$

$d=\frac{m\lambda }{\sin \theta _m}-----1$

Position of bright fringe is given by

$y=\tan \theta _m\cdot L$

$\tan \theta _m=\frac{y}{L}$

$\theta _m=\tan^{-1}(\frac{y}{L})$

Put the value of $\theta _m$ in eq. 1

$d=\frac{m\lambda }{\sin (\tan^{-1}(\frac{y}{L}))}$

Therefore $N=d^{-1}$

$N=\frac{\sin (\tan^{-1}(\frac{y}{L}))}{m\lambda }$

for $m=1$

$N=\frac{\sin (\tan^{-1}(\frac{1.9\times 10^{-2}}{0.8}))}{1\times 590\times 10^{-9}}$

$N=40243\ line/m$

$N=40\ line/mm$

4 0

4 years ago

A 0.775-m3 rigid tank initially contains air whose density is 1.18 kg/m3. The tank is connected to a high-pressure supply line t

Rama09 [41]

Answer:

2.9 kg

Explanation:

Given that a 0.775-m3 rigid tank initially contains air whose density is 1.18 kg/m3.

According to the definition of density

Density = mass/volume

1.18 = mass / 0.775

Mass = 1.18 × 0.775

Mass = 0.9145 kg

Given that the tank is connected to a high-pressure supply line through a valve. The valve is opened, and air is allowed to enter the tank until the density in the tank rises to 4.95 kg/m3.

Using the same density formula

Density = mass/volume

4.95 = mass / 0.775

mass = 3.83625 kg

To determine the mass of air that has entered the tank, take away the mass of the air initial in the tank from the mass calculated

Mass = 3.83625 - 0.9145

Mass = 2.923kg

Therefore, the mass of air that has entered the tank is 2.9 kg approximately.

3 0

3 years ago

An AC circuit has an RMS voltage of 80 VAC. What's the circuit's average voltage?

yaroslaw [1]

-- The RMS value of an AC waveform is (1/2)(√2) x (peak value)

So the peak value is (√2) x (RMS value)

-- The Average value of an AC waveform is (2/π) x (peak value)

So the peak value is (π/2) x (Average value).

-- So far, this is all very entertaining, but how does it help us answer the question.

Well, we found the peak value in terms of the RMS and in terms of the Average. So we can set these equal to each other, and solve for the Average in terms of the RMS. This sounds like such a good plan, I think I'll do it !

Peak = (√2) x (RMS value) and Peak also = (π/2) x (Average value).

So (√2) · RMS = (π/2) · Average .

Divide each side by π : (√2) · RMS / π = (1/2) · Average

Multiply each side by 2 : Average = (2/π) · (√2) · RMS .

You said that the RMS value is 80 V, so

Average = (2/π) · (√2) · (80)

Average = (2 · √2 / π) · (80)

Average = 160√2 / π

Average = 72 volts . (But be sure to read the 'gotcha' below.)

Now I'll go ahead and tell you the 'gotcha':

All of these numbers are true, as far as they go. But the 'average' is only true for 1/2 cycle of an AC wave. Picture an AC wave in your mind. You'll see that it spends just as much time being negative as it spends being positive. So the 'average' of any number of AC whole cycles is zero.

7 0

3 years ago

The center-seeking change in velocity of an object moving in a circle is:

NeTakaya

The center-seeking change in velocity of an object moving in a circle is the centripetal acceleration.

So, by Newton's laws, we know that an object moving with a given velocity will remain in constant motion with a constant velocity until we apply an acceleration.

So we define acceleration as the rate of change of the velocity, also remember that velocity is a vector (has magnitude and direction), so, if there is a change the direction of the velocity, we have an acceleration that causes that.

In circular motion, the velocity vector is always perpendicular to the radius of the circle, and it can only be possible if the velocity direction is changing constantly. This will happen because of something called centripetal acceleration.

This acceleration points radially inwards (to the center of the circle) so is also perpendicular to the velocity of the moving object, and this is what causes the constant change in the direction of the velocity of the moving object.

Just to give an example, if you have a string with a mass on one end, and with your hand, you rotate the mass (from the string), the tension of the string would be the centripetal acceleration.

If you want to learn more about circular motion, you can read:

brainly.com/question/2285236

5 0

3 years ago

Read 2 more answers

According to Ohm’s law, which is stated as I = V ÷ R, which two sentences are true?

ahrayia [7]

Answer:

2nd and 4th statements.

Explanation

If voltage is constant ( k ) and I = V / R,

Then I is inversely proportional to R so if I increases R decreases and vice versa, according to that the second statement is correct not the first.

if current is constant, then v is directly proportional to R and vice versa..the 3rd statement is wrong

if resistance is constant v is directly proportional to I, then only the 4th is correct not the 5th

5 0

2 years ago