What is true about solar energy hitting earth?

The photoelectric work function of a metal is the minimum energy needed to eject an electron by irradiating the metal with light

Vlada [557]

Answer:

Minimum required frequency is υmin = 654.9 x 10¹² Hz

Explanation:

The energy of a photon is given by the equation:

E = hυ

where,

E = energy of photon

h = Plank's Constant = 6.626 x 10⁻³⁴ J.s

υ = frequency

The minimum energy of photon, must be equal to the work function of Calcium.

Emin = ∅₀ = h(υmin)

υmin = ∅₀/h

where,

υmin = minimum frequency

∅₀ = work function = 4.34 x 10⁻¹⁹ J

Therefore,

υmin = 4.34 x 10⁻¹⁹ J/6.625 x 10⁻³⁴ J.s

3 0

3 years ago

What color would the sky be if the atmosphere was 100% large molecules and particles like dust and water?

DedPeter [7]

Answer:

Gray-ish looking like as if the atmosphere were full of only pollution.

3 0

3 years ago

Definition of definite

KIM [24]

Google definition: a statement of the exact meaning of a word, especially in a dictionary.

the degree of distinctness in outline of an object, image, or sound, especially of an image in a photograph or on a screen.

My definition: The meaning or deintion of any word.

5 0

3 years ago

A toy cart at the end of a string 0.70 m long moves in a circle on a table. The cart has a mass of 2.0 kg and the string has a b

luda_lava [24]

Given that the mass of the toy cart is 2.0 kg and and the acceleration is unknown, the normal formula would be a=f/m where a is acceleration, f is force and m is mass but the string's breaking strength is 40n so I think the formula in this case will be f is greater than m*a
40 is greater than 2a
40 is greater than 2a
40/2 is greater than 2a/2
20m/s² is greater than a
Therefore the maximum speed the toy cart should have should be less than 20m/s²

8 0

3 years ago

The length of a simple pendulum is 0.81 mand the mass of the particle (the "bob") at the end of the cable is0.23 kg. The pendulu

Gemiola [76]

Answer:

$\displaystyle w=3.478\ rad/sec$

$M=0.0182\ J$

$v=0.398\ m/s$

Explanation:

<u>Simple Pendulum</u>

It's a simple device constructed with a mass (bob) tied to the end of an inextensible rope of length L and let swing back and forth at small angles. The movement is referred to as Simple Harmonic Motion (SHM).

(a) The angular frequency of the motion is computed as

$\displaystyle w=\sqrt{\frac{g}{L}}$

We have the length of the pendulum is L=0.81 meters, then we have

$\displaystyle w=\sqrt{\frac{9.8}{0.81}}$

$\displaystyle w=3.478\ rad/sec$

(b) The total mechanical energy is computed as the sum of the kinetic energy K and the potential energy U. At its highest point, the kinetic energy is zero, so the mechanical energy is pure potential energy, which is computed as

$U=mgh$

where h is measured to the reference level (the lowest point). Please check the figure below, to see the desired height is denoted as Y. We know that

$H+Y=L$

And

$H=L\ cos\alpha$

Solving for Y

$Y=L(1-cos\alpha )$

$Since\ \alpha=8.1^o, L=0.81\ m$

$Y=0.0081\ m$

The potential energy is

$U=mgh=0.23\ kg(9.8\ m/s^2)(0.0081\ m)$

$U=0.0182\ J$

The mechanical energy is, then

$M=K+U=0+U=U$

$M=0.0182\ J$

(c) The maximum speed is achieved when it passes through the lowest point (the reference for h=0), so the mechanical energy becomes all kinetic energy (K). We know

$\displaystyle K=\frac{mv^2}{2}$

Equating to the mechanical energy of the system (M)

$\displaystyle \frac{mv^2}{2}=0.0182$

Solving for v

$\displaystyle v=\sqrt{\frac{(2)(0.0182)}{0.23}}$

$v=0.398\ m/s$

4 0

3 years ago