The value of a scientific variable can change. (A)
Hint hint: That's why it's called a "variable". If it always remained the same, then it would've been called a "constant".
It is less dense than the water above it and so it the heated less dense water rises upwards to replace the denser water and the denser water falls below to the heating element below, and this also becomes less dense and the circle continues, thus setting up the convection current.
Similar principle is applied in convection current for land and sea breezes.
Explanation :
There are many types of simple machines i.e. lever, wedge, pulley, wheel and axle etc.
Fulcrum is the pivot point about which the lever turns. When the position of the fulcrum is shifted, the position of effort changes.
There are three classes of the lever as class 1, class 2 and class 3.
Class 1 includes seesaws and scissors.
class 2 includes wheelbarrow
class 3 includes tongs and tweezers.
Answer:
7.39ev
Explanation:
Energy levels are found inside the atom. Electrons occupy these energy levels depending on the energy they possess. Electrons can move from one energy level to another due to absorption or emission of a photon or other factors. As the electron, jumps from a higher energy level to a lower energy level emitting a photon of measurable frequency, the photon carries energy equal to the amount of energy between the gap of the levels. This idea was first proposed by Neils Bohr and became the forerunner of the wave mechanical model of the atom.
Hence the energy of a photon is the energy of the gap between the two energy levels. Since Ea= 2.48ev and Eg= 10.38 ev.
If an electron jumps from Ea to Eg, the energy of the photon absorbed is given by;
E=Eg-Ea
E= 10.38ev - 2.48ev
E= 7.39ev
