Answer:
Measurements are an important part of comparing things, as they provide the basis on comparing objects to other objects. Measurements allow us to recognize three hours and see how it's shorter than five hours, without having to observe the hours passing by themselves.
Answer:
By altering the quantum interactions of the electrons in the atoms of a metal's atoms, scientists from the University of Leeds have generated magnetism in metals that aren’t normally magnetic.
Explanation:
Water expands when it freezes (that's why you should never put closed, fully filled water bottles in the freezer !)
Answer: Partial pressure of nitrogen and xenon are 288mmHg and 548 mmHg respectively.
Explanation:
The partial pressure of a gas is given by Raoult's law, which is:

where,
= partial pressure of substance A
= total pressure
= mole fraction of substance A
We are given:


Mole fraction of a substance is given by:

And,

Mole fraction of nitrogen is given as:

Molar mass of
= 28 g/mol
Molar mass of
= g/mol
Putting values in above equation, we get:


To calculate the mole fraction of xenon, we use the equation:



Thus partial pressure of nitrogen and xenon are 288mmHg and 548 mmHg respectively.
Answer: Replace the orange light source with a higher frequency light source
Explanation:
To expel electrons from a piece of metal, the incoming light must have a minimum frequency to cause a photoelectric effect, i.e., the ejection of photoelectrons from a metal surface, which is also known as the metal's threshold frequency.
If v = frequency of incident photon and vth= threshold frequency, then,
- For v < vth, there will be no ejection of photoelectron.
- For v = vth, photoelectrons are just ejected from the metal surface, in this case, the kinetic energy of the electron ejected is zero
- For v > vth, then photoelectrons will come out of the surface along with kinetic energy
Therefore, we would have to increase the frequency of incident light so that it becomes greater than the threshold frequency of that surface, and consequently a photoelectric process takes place.