Answer: Option (a) is correct.
Explanation:
When an object moves from its initial position, it acquires some energy. This energy is called kinetic energy, as it is governed by the motion of an object.
The formula to calculate kinetic energy is as follows.
kinetic energy =
where,
m = mass of object
v = velocity of object
Thus, it is concluded that kinetic energy is the energy an object has due to its motion.
(2) The concentration of reactants and products are equal.
(3) The rate of the forward reaction is equal to the rate of the reverse reaction.
(4) The number of moles of reactants is equal to the number of moles of product.
The universe is expanding is as the galaxies are moving away from each other, and the temperature of the universe is decreasing. Therefore, option (1) is correct.
First scientists theorized that as the universe is expanding and its temperature has gradually decreased. The universe has been expanding since the Big Bang and, as it expands, it’s temperature cooling down.
The temperature of the universe can be measured by looking at the cosmicmicrowave background (CMB). The temperature an be estimated by the thermal radiation left over from the BigBang.
The CMB scientists have been investigating that its temperature has been dropping off gradually as our universe expands out and the current average temperature of the cosmos is estimated about 2.73 Kelvin.
The point of the Big Bang from the Big bang theory is described as densesingularity and infinitely hot. The energy from the Big Bang distributed as the universe expands and gives the cooling effect.
But new research suggests otherwise that the temperature of the earth is actually increasing as it expands. Therefore, the temperature of universe increasing with its expansion.
Learn more about universe expanding, here:
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B. Reflection
C. Diffraction
D. Resonance
(2) silver (4) thallium
Answer: option (4) thallium.
Explanation:
1) You have to look at the normal boling and mleting points of the elements.
2) To be liquid the normal melting point must be lower than 758 K and the normal boiling point must be greater than 758 K.
3) The look at the data in a handbook of properties or in internet, and build a table.
4) The given temperature, 758K, is 758 - 273.15 = 484.85 °C.
Element Normal melting Normal boiling State at 484.85 °C
point (°C) point (°C)
(1) gold 1064 2700 solid
(2) silver 961.8 2162 solid(3) platinum 1768 3825 solid
(4) thallium 303.5 1457.8 liquidThen, the only element of the choices whose melting point is less than 758 K (484.85) and its boiling point is greater than that, at 1 atm is thallium. So, it is liquid.