All categories

4 years ago

Why is it safe to watch an eclipse of the Moon but not an eclipse of the Sun

1 answer:

8 0

A solar eclipse occurs when the moon crosses in front of the Sun, blocking some or all of its rays. A lunar eclipse happens when the moon is directly behind the earth, blocking the moon from receiving light. The only light comes from the light on earth's reflected shadow.

You can look at a lunar eclipse because there is very little light or none at all. You can't look at a solar eclipse because you are looking directly at the sun unless it is complete. Before totality, only some of the Sun is blocked, causing your pupils dilate to let in more light. Since they do this, more of the Sun's rays can be let in to the eye, which effectively allows your eyes to burn.

Some doctors and eye care specialists say that after someone complains of blindness after looking at a solar eclipse unaided, they can see what the Sun and moon looked like at the time that they looked at it, as it is burned onto their retinas.

You might be interested in

What number will be shown by hydrometer if sunk in pure water ?

serious [3.7K]

The hydrometer displays the density of the liquid you stick it in, COMPARED TO WATER.

If you stick it in pure water, it should read 1.00 . This is a good way to check your hydrometer and see whether it's reading correctly ("calibrated").

7 0

3 years ago

Read 2 more answers

A stone is thrown upward from a bridge at a speed of 10 m/s. It narrowly misses the bridge on the way back down, and hits the wa

Hoochie [10]

Explanation:

Je2jjwjwnjwnwj23j3jjej2n3neee;e

3 0

3 years ago

Read 2 more answers

Viggo needs to take an extended leave of absence from work for personal reasons. The remaining employees are required to perform

Romashka-Z-Leto [24]

Answer:

The answer is C. Resistance

Explanation:

Viggo needs to take an extended leave of absence from work for personal reasons. The remaining employees are required to perform Viggo’s duties, and Dewitt is the only one who understands how to do many of them. Though Dewitt’s body is unable to maintain the alarmed state it entered when he learned of the additional work, he remains stressed out over the weeks that follow. He hopes Viggo will return before he becomes truly overwhelmed. Dewitt is in the RESISTANCE stage of the general adaptation syndrome (GAS).

4 0

3 years ago

(a) What frequency is received by a person watching an oncoming ambulance moving at 110 km/h and emitting a steady 800-Hz sound

Vesnalui [34]

Answer:

a) 877.76 Hz

b) 734.88 Hz

Explanation:

This kind of exercise is about explaining the Doppler efect.

The doppler effect is the change in frequency of a wave in relation to an observer who is moving relative to the wave source. In this case, a person watching an ambulance.

This shifting can be calculated using the following expression:

f' = (V - Vo / V - Vs) * f

Where:

V: speed of the sound in the medium (345 m/s in this case)

Vo: speed of the observer, in this case 0, cause the person is standing still.

Vs: speed of the source (in this case 110 km/h)

Let's convert the Vs from km/h to m/s

Vs = 110 * 1000 m/km * 1h/3600s = 30.56 m/s

Now that we have the data, let's calculate the frequency before the ambulance pass, and then, after.

a) using the above expression, we have the following:

f' = (345 - 0 / 345 - 30.56) * 800

f' = (1.0972) * 800

f' = 877.76 Hz

b) In this part, we'll use the same expression, with the difference that, as the ambulance has passed the person, the sign of the Vs change. This is because before, the ambulance was behind the person, and now it's in front passing. So, the frequency here is:

f = (345 - 0 / 345 + 30.56) * 800

f = 0.9186 * 800

f' = 734.88 Hz

7 0

3 years ago

What is the main difference between velocity and speed?

Marina86 [1]

Speed is scalar, meaning it's only going to be like 74 mph, doesn't matter which direction. Velocity is a vector, meaning it has direction. You can go -74mph when talking about velocity, not speed.

4 0

3 years ago