Answer:
the charge carriers have an energy 2.8 10⁻¹⁹ J
Explanation:
The energy in a diode is conserved so the energy supplied must be equal to the energy emitted in the form of photons.
The energy of a photon is given by the Planck expression
E = h f
the speed of light, wavelength and frequency are related
c = λ f
we substitute
E =
a red photon has a wavelength of lam = 700 nm = 700 10⁻⁹ m
we calculate the energy
E = 6.626 10⁻³⁴ 3 10⁸/700 10⁻⁹
E = 2.8397 10⁻¹⁹J
therefore the charge carriers have an energy 2.8 10⁻¹⁹ J,
Answer:
The coefficient of static friction is 0.29
Explanation:
Given that,
Radius of the merry-go-round, r = 4.4 m
The operator turns on the ride and brings it up to its proper turning rate of one complete rotation every 7.7 s.
We need to find the least coefficient of static friction between the cat and the merry-go-round that will allow the cat to stay in place, without sliding. For this the centripetal force is balanced by the frictional force.

v is the speed of cat, 

So, the least coefficient of static friction between the cat and the merry-go-round is 0.29.
Answer:
2.2 µm
Explanation:
For constructive interference, the expression is:
Where, m = 1, 2, .....
d is the distance between the slits.
Given wavelength = 597 nm
Angle,
= 15.8°
First bright fringe means , m = 1
So,
Also,
1 nm = 10⁻⁹ m
1 µm = 10⁻⁶ m
So,
1 nm = 10⁻³ nm
Thus,
<u>Distance between slits ≅ 2.2 µm</u>
The vertical force exerted on the lawn is 68.8 N downward
Explanation:
The vertical force exerted by the lawnmower on the lawn is equal to the vertical component of the force applied, therefore:

where
F is the magnitude of the force applied
is the angle between the direction of the force and the horizontal
In this problem:
F = 120 N
Substituting,

where the negative sign means the direction of the force is downward.
Learn more about vector components and forces here:
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Answer:
36 kg
Explanation:
To answer this question, a few assumptions have to be made:
- That the temperature on the day is 35 °C
- That all the heat from the elephant is goes to warming/evaporating the water on the surface of the elephant
Energy released per hour = 2500 J/s * 3600 s = 9 000 000 J
Q = mcΔT
9 000 000 J= m *4.186 J/g-K * (373K - 308K) + m*2260 J/g
m = 36 000 g = 36 kg