Answer:
We show added energy to a system as +Q or -W
Explanation:
The first law of thermodynamics states that, in an isolated system, energy can neither be created nor be destroyed;
Energy is added to the internal energy of a system as either work energy or heat energy as follows;
ΔU = Q - W
Therefore, when energy is added as heat energy to a system, we show the energy as positive Q (+Q), when energy is added to the system in the form of work, we show the energy as minus W (-W).
Answer:
Explanation:
The formula for the force exerted between two charges is
where k is the Coulomb constant.
The charges are identical, so we can write the formula as
When light moves from a medium with higher refractive index to a medium with lower refractive index, the critical angle is the angle above which there is no refracted light, and all the light is reflected. The value of this angle is given by
where n2 and n1 are the refractive indices of the second and first medium, respectively.
In the first part of the problem, light moves from glass to air (
) and the critical angle is
. This means that we can find the refractive index of glass by re-arranging the previous formula:
Now the glass is put into water, whose refractive index is
. If light moves from glass to water, the new critical angle will be
Corrosive. It’s something that tends to cause corrosion, and it means to destroy or damage things slowly by chemical action.
Answer:
Hoop will reach the maximum height
Explanation:
let the mass and radius of solid ball, solid disk and hoop be m and r (all have same radius and mass)
They all are rolled with similar initial speed v
by the law of conservation of energy we can write
for solid ball
putting in the above equation and solving we get
now for solid disk
putting in the above equation and solving we get
for hoop
putting in the above equation and solving we get
clearly from the above calculation we can say that the Hoop will reach the maximum height