The answer is A. The Sun and all the planets revolve around Earth.
Aristotle believed that the Earth was the centre of the solar system, and the Sun and the planets orbited around it. He believed that the universe was composed of Earth-like bodies, which were at rest, and of heavenly bodies, which were in perpetual motion.
Non metals tend to have higher ionization energies
First is melts then it expands next it gets cooler Finally it gains ener. Hope this helps you out.
Answer:
the radii of curvature is 30 cm.
Explanation:
given,
object is place at = 45 cm
image appears at = 90 cm
focal length = ?
refractive index = 1.5
radii of curvature = ?
f = 30 cm
using lens formula
R = 30 cm
hence, the radii of curvature is 30 cm.
Answer: Δβ (dB) = -13.1dB
Explanation:
The intensity of sound is inversely proportional to the square of the distance between them.
I ∝ 1/r²
I₁/I₂= r₂²/r₁² .....1
When the listener increases his distance from the source by a factor of 4.49.
Then,
r₂/r₁= 4.49
From equation 1
I₁/I₂ = (4.49)²
I₁/I₂ = 20.16
I₂/I₁ = 1/20.16
The change in sound intensity in dB can be given as
Δβ (dB) = 10 log(I₂/l₁) = 10log(1/20.6) = -13.1dB
