The energy carried by a single photon of frequency f is given by:
where
is the Planck constant. In our problem, the frequency of the photon is 
, and by using these numbers we can find the energy of the photon:
where
If we have less power, we most likely have
1 answer:
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The astronaut will take 300 seconds
Explanation:
We can solve this problem by using the law of conservation of momentum.
In fact, the total momentum of the astronaut+object system must be conserved.
Initially, they are both at rest, so their total momentum is zero:
After the astronaut throws the object, their total momentum is:
where:
M = 80 kg is the mass of the astronaut
V is the final velocity of the astronaut
m = 500 g = 0.5 kg is the mass of the object
v = 8.0 m/s is the velocity of the object
Since momentum is conserved, we can write
And solving for V,
Which means that he starts moving at 0.05 m/s in the direction opposite to the object.
Now the astronaut needs to cover a distance of
d = 15.0 m
And his speed is
v = 0.05 m/s
Therefore, the time taken is
Learn more about momentum here:
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Answer:
The speed of the electron is 1.371 x 10⁶ m/s.
Explanation:
Given;
wavelength of the ultraviolet light beam, λ = 130 nm = 130 x 10⁻⁹ m
the work function of the molybdenum surface, W₀ = 4.2 eV = 6.728 x 10⁻¹⁹ J
The energy of the incident light is given by;
E = hf
where;
h is Planck's constant = 6.626 x 10⁻³⁴ J/s
f = c / λ
Photo electric effect equation is given by;
E = W₀ + K.E
Where;
K.E is the kinetic energy of the emitted electron
K.E = E - W₀
K.E = 15.291 x 10⁻¹⁹ J - 6.728 x 10⁻¹⁹ J
K.E = 8.563 x 10⁻¹⁹ J
Kinetic energy of the emitted electron is given by;
K.E = ¹/₂mv²
where;
m is mass of the electron = 9.11 x 10⁻³¹ kg
v is the speed of the electron
Therefore, the speed of the electron is 1.371 x 10⁶ m/s.
Answer:19.5 m
Explanation:
Given
coefficient of kinetic Friction
Initial speed
Friction is present so it tries to stop to the object and stops it completely after moving certain distance let say s
maximum deceleration provided by friction is
using equation of motion
where