Answer:
Explanation:
The energy of a photon is given by the equation 
, where h is the <em>Planck constant</em> and f the frequency of the photon. Thus, N photons of frequency f will give an energy of 
.
We also know that frequency and wavelength are related by 
, so we have 
, where c is the <em>speed of light</em>.
We will want the number of photons, so we can write
We need to know then how much energy do we have to calculate N. The equation of power is 
, so for the power we have and considering 1 second we can calculate the total energy, and then only consider the 4% of it which will produce light, or better said, the N photons, which means it will be 
.
Putting this paragraph in equations:
.
And then we can substitute everything in our equation for number of photons, in S.I. and getting the values of constants from tables:
Answer;
= 4 m is the length of the man's shadow.
Explanation;
2/x=6/(8+x) cross multiply.
6x=2(8+x)
6x=16+2x
6x-2x=16
4x=16
x=2=16/4
x=4 m. is the length of the man's shadow.
Answer:
Explanation:
Given
Each student exert a force of 
Let mass of car be m
there are 18 students who lifts the car
Total force by 18 students 
therefore weight of car 
mass of car 
(b)
I'm not too sure what your asking but here are two answers that may help.
The ear drum amplifies the vibrations.
The cochlea changes vibrations into electric signals.
The reaction of reduction always undergoes with the cathode, the positive ion will migrate towards the cathode with the negative charge whilst the anode always has oxidation reaction. These two types of reaction does not change.
