Force on a moving charge is given by formula
here we know that this force will be maximum when velocity is perpendicular to magnetic field
here we know that
now we have
A city is considering switching to geothermal power for their electricity needs. Which of the following is an advantage of this
1 answer:
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Answer:
A fan with an energy efficiency of 30 % would need 62.5 watts to bring a desired volume flow of 0.05 cubic meters per second through a cross-sectional area of 20 square centimeters.
Explanation:
Complete statement is: <em>Determine the power that needs to besupplied by the fan if the desired velocity is 0.05 cubic meters per second and the cross-sectional area is 20 square centimeters.</em>
From Thermodynamics and Fluid Mechanics we know that fans are devices that work at steady state which accelerate gases (i.e. air) with no changes in pressure. In this case, mechanical rotation energy is transformed into kinetic energy. If we include losses due to mechanical friction, the Principle of Energy Conservation presents the following equation:
(Eq. 1)
Where:
- Efficiency of fan, dimensionless.
- Electric power supplied fan, measured in watts.
- Rate of change of kinetic energy of air in time, measured in watts.
From definition of kinetic energy, the equation above is now expanded:
(Eq. 2)
Where:
- Density of air, measured in kilograms per cubic meter.
- Volume flow, measured in cubic meters per second.
- Cross-sectional area of fan, measured in square meters.
If we know that ,
,
and
, the power needed to be supplied by the fan is:
A fan with an energy efficiency of 30 % would need 62.5 watts to bring a desired volume flow of 0.05 cubic meters per second through a cross-sectional area of 20 square centimeters.
In order to calculate the angle, we can use the formula below for a constructive interference (the interference is constructive because the fringe is bright):
Where d is the distance between the slits, m is the order of the interference and lambda is the wavelength.
So, using d = 8.25 * 10^-5, m = 2 and lambda = 4.5 * 10^-7, we have:
Therefore the correct option is the second one.