Answer:
0° C
Explanation:
Given that
Mass of ice, m = 50g
Mass of water, m(w) = 50g
Temperature of ice, T(i) = 0° C
Temperature of water, T(w) = 80° C
Also, it is known that
Specific heat of water, c = 1 cal/g/°C
Latent heat of ice, L(w) = 89 cal/g
Let us assume T to be the final temperature of mixture.
This makes the energy balance equation:
Heat gained by ice to change itself into water + heat gained by melted ice(water) to raise its temperature at T° C = heat lost by water to reach at T° C
m(i).L(i) + m(i).c(w)[T - 0] = m(w).c(w)[80 - T], on substituting, we have
50 * 80 + 50 * 1(T - 0) = 50 * 1(80 - T)
4000 + 50T = 4000 - 50T
0 = 100 T
T = 0° C
Thus, the final temperature is 0° C
The answer to this question is a) sulfur
Answer:
They have a dual wave-particle nature.
Explanation:
Electromagnetic waves consist of periodic oscillations of electric and magnetic field in a plane perpendicular to the direction of motion of the wave (in fact, they are also classified as transverse waves).
Electromagnetic waves have a wave nature, however they also have particle nature - in fact, it has been proved in some experiment (e.g. photoelectric effect) that in some conditions they act as packets of particles - called photons. Therefore, the option
They have a dual wave-particle nature.
is correct.
Other options are wrong because:
They are all invisible. --> False because visible light (which is part of the electromagnetic spectrum, so they are electromagnetic waves) is visible
They can only travel without a medium. --> False because they can also travel in a vacuum
They are slower than sound waves. --> False because they travel much faster (they travel at the speed of light in a vacuum, 
, while sound travels at 343 m/s in air, for instance)
<h2>2) Copernicus rediscovered Aristarchus’s heliocentric model.</h2>
Before Copernican Revolution, people did believe in the ptolemain model that establishes the description of the Universe with the earth at the center having sun, moon, starts and planets all orbited earth. On the other hand, the heliocentric model establishes the sun at the center of the solar system and this starts with the publication of Nicolas Copernicus named <em>De revolutionibus orbium coelestium.</em>
<h2>5) Newton’s theories of gravity increased understanding of the movement of planets.</h2>
The revolution ended with Isaac Newton's work over a century later. As you well know, Newton was both a physicist and mathematician, better known for his prodigal work called <em>Philosophiæ Naturalis Principia Mathematica. </em>In this revolution, he is known for his laws of motion and universal gravitation increasing understanding of the movement of planets.
