Answer:
and 
Explanation:
The wavelength of a visible light is 727.3 nm.

The formula is as follows :

f is the frequency of the visible light

Energy of a photon is given by :
E = hf, h is Planck's constant

Red color has a frequency of
and energy per photon is
.
Answer:
1.58 Hz
Explanation:
The frequency of the simple pendulum is given by
f = 1/T
= 1/2π√g/l
In this problem, I = 10.0 cm = 0.1 m
f = 1/2π√9.8/0.1
= 1.58 Hz
Answer:
Explanation:
From the given information:
The initial PE
= m×g×h
= 5 kg × 9.81 m/s² × 10 m
= 490.5 J
The change in Potential energy P.E of the box is:
ΔP.E = 
ΔP.E = 0 -
ΔP.E = 
If we take a look at conservation of total energy for determining the change in the internal energy of the box;


this can be re-written as:

Here, K.E = 0
Also, 70% goes into raising the internal energy for the box;
Thus,


ΔU = 343.35 J
Thus, the magnitude of the increase is = 343.35 J
Explanation:
Given that,
Charge 1, 
Charge 2, 
The distance between charges, r = 1.99 m
To find,
The electrostatic force and its nature
Solution,
(a) The electric force between two charges is given by :



(b) As the magnitude of both charges is positive, then the force between charges will be repulsive.
Therefore, this is the required solution.