Answer:
If the height is in metres, the speed is 24.25m/s
<h2>
Answer: Infrared light</h2>
A dark nebula is a cloud of dust and cold gas, which does not emit visible light and hides the stars it contains.
These types of nebulae are composed mainly of the hydrogen they obtain from nearby stars, which is their fuel.
It is using infrared light that we can "observe" and analyze in detail what happens in the inner parts of these nebulae.
It is given that for the convex lens,
Case 1.
u=−40cm
f=+15cm
Using lens formula
v
1
−
u
1
=
f
1
v
1
−
40
1
=
15
1
v
1
=
15
1
−
40
1
v=+24.3cm
The image in formed in this case at a distance of 24.3cm in left of lens.
Case 2.
A point source is placed in between the lens and the mirror at a distance of 40 cm from the lens i.e. the source is placed at the focus of mirror, then the rays after reflection becomes parallel for the lens such that
u=∞
f=15cm
Now, using mirror’s formula
v
1
+
u
1
=
f
1
v
1
+
∞
1
=
15
1
v=+15cm
The image is formed at a distance of 15cm in left of mirror
Aristarchus(310-230 BC)
Aristarchus was a Greek Astronomer and Mathematician. He proposed the heliocentric model of the Solar System. He attempted to measure the distances from the moon to the sun.
Aristotle (334-322 BC)
<span>Aristotle was a Greek Philosopher. He was the first person to propose this historical model. He thought the Earth was in the center of all celestial beings. His idea was that the Earth was in the middle of the sun, moon, stars, and other planets. </span>
Ptolemy(100-170 CE)
<span>Ptolemy was a astronomer and a geographer and a mathematician! He proposed the geocentric model. He believed that a celestial body could go at a constant speed in a perfect circle. It was called the "wheels-on-wheels" system. It had better observations than the model that had came before his. His geocentric model was used for the next 14 centuries! </span>
Kepler(1571-1630)
<span>German astronomer and mathematician, Johannes Kepler, studied very hard and closely, and he found out that the planets did not fit the observations that were made by previous explorers. He found one that fit the best out of them all! He found three principles, called Kepler's Laws. </span>
