Wavelength=velocity/frequency
Time a.k.a period = 1/frequency
Step 1: solve for frequency using the first equation
0.79m = 355/frequency
Frequency=280.45 Hz
Step 2: solve the period using the second equation
1/280.45 = 0.00357=3.57*10^-3 seconds
Answer:
The heat rejected is 146J.
The work done by the engine is 54J.
The thermal efficiency is 0.27
Explanation:
The efficiency of the carnot engine, which is working between a hot source at a temperature and a cold source at a temperature , is given by:
The normal boiling point of water is 373 K. ()
The temperature of triple point of water is 273.15 K ()
Answer:
There are atoms when the sample of cerium is 20 seconds old.
Explanation:
The decay of isotopes is modelled after the following exponential expression:
(1)
Where:
- Initial number of atoms, dimensionless.
- Current number of atoms, dimensionless.
- Time, measured in seconds.
- Half-time, measured in seconds.
Now we clear the half-time within (1):
If we know that , and , then the half-life of the isotope is:
And the decay equation for the sample is described by:
Lastly, if we get that , then the activity of the sample of cerium is:
There are atoms when the sample of cerium is 20 seconds old.
The idea that objects only change their velocity due to a force is encapsulated in Newton's first law. Newton's first law: An object at rest remains at rest, or if in motion, remains in motion at a constant velocity unless acted on by a net external force.
Answer:
The electric flux remains unchanged
Explanation:
From Gauss law the Electric flux is directly proportional to the number of electric field lines passing through a surface. The number of field lines passing through a surface become if the radius is doubled becomes 1/4th that is when radius of the Gaussian surface is doubled, but at the same time, the surface area has increased 4 times , so the electric flux remains unchanged