Potential energy is due to_blank_?
2 answers:
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Answer:
a) 0 b) 29.9 N c) 21.7 N d) -17.4 N e) -13.0 N f) -17.4 N g) 16.9 N
h) 24.3 N θ = 44.2º
Explanation:
a) As the electric force is exerted along the line that joins the charges, due to any of the charges A or C has non-zero x-coordinates, the force has no x components either.
So, Fcax = 0
b) Similarly, as Fx = 0, the entire force is directed along the y-axis, and is going upward, due both charges repel each other.
Fyca = k*qa*qc / rac² = (9.10⁹ N*m²/C²*(2.79)*(1.07)*10⁻⁸ C²) / 9.00 m²
Fyca = 29. 9 N
c) In order to get the magnitude of the force exerted by B on C, we need to know first the distance between both charges:
rbc² = (3.00 m)² + (4.00m)² = 25.0 m²
⇒ Fbc = k*qb*qc / rbc² = (9.10⁹ N*m²/C²*(5.64)*(1.07)*10⁻⁸ C²) / 25.0 m²
⇒ Fbc = 21.7 N
d) In order to get the x component of Fbc, we need to get the projection of Fcb over the x axis, taking into account that the force on particle C is attractive, as follows:
Fbcₓ = Fbc * cos (-θ) where θ, is the angle that makes the line of action of the force, with the x-axis, so we can write:
cos θ = x/r = 4.00 / 5.00 m =
Fcbx = 21.7*(-0.8) = -17.4 N
e) The y component can be calculated in the same way, projecting the force over the y-axis, as follows:
Fcby = Fcb* sin (-θ) = 21.7* (-3.00/5.00) = -13.0 N
f) The sum of both x components gives :
Fcx = 0 + (-17.4 N) = -17.4 N
g) The sum of both y components gives :
Fcy = 29.9 N + (-13.0 N) = 16.9 N
h) The magnitude of the resultant electric force acting on C, can be found just applying Pythagorean Theorem, as follows:
Fc = √(Fcx)²+(Fcy)² = (17.4)² + (16.9)² = 24.3 N
The angle from the horizontal can be found as follows:
Ф = arc tg (16.9 / 17.4) = 44.2º
Answer:
material work function is 0.956 eV
Explanation:
given data
red wavelength 651 nm
green wavelength 521 nm
photo electrons = 1.50 × maximum kinetic energy
to find out
material work function
solution
we know by Einstein photo electric equation that is
for red light
h ( c / λr ) = Ф + kinetic energy
for green light
h ( c / λg ) = Ф + 1.50 × kinetic energy
now from both equation put kinetic energy from red to green
h ( c / λg ) = Ф + 1.50 × (h ( c / λr ) - Ф)
Ф =( hc / 0.50) × ( 1.50/ λr - 1/ λg)
put all value
Ф =( 6.63 × (3 ×
) / 0.50) × ( 1.50/ λr - 1/ λg)
Ф =( 6.63 × (3 ×
) / 0.50 ) × ( 1.50/ 651×
- 1/ 521 ×
)
Ф = 1.5305 × J × ( 1ev / 1.6 ×
J )
Ф = 0.956 eV
material work function is 0.956 eV